Biological Invasions 4: 115–143, 2002.
© 2002 Kluwer Academic Publishers. Printed in the Netherlands.

Review

No longer the pristine confines of the world ocean: a survey of
exotic marine species in the southwestern Atlantic

Jose Maria (Lobo) Orensanz1, Evangelina Schwindt2,∗, Guido Pastorino3,
Alejandro Bortolus4, Graciela Casas1, Gustavo Darrigran5, Rodolfo Elı́as2, Juan J. López
Gappa3, Sandra Obenat2, Marcela Pascual6, Pablo Penchaszadeh3, Marı́a Luz Piriz1,
Fabrizio Scarabino7, Eduardo D. Spivak2 & Eduardo A. Vallarino2

1Centro Nacional Patagónico, Puerto Madryn, Argentina; 2Universidad Nacional de Mar del Plata, Mar del
Plata, Argentina; 3Museo Argentino de Ciencias Naturales, Buenos Aires, Argentina; 4Department of Ecology
and Evolutionary Biology, Brown University, 80 Waterman St., Providence, RI 02912, USA; 5Facultad de Ciencias
Naturales y Museo, Universidad Nacional de La Plata, La Plata, Argentina; 6Instituto de Biologı́a
Marina y Pesquera, San Antonio Oeste, Argentina; 7Museo Nacional de Historia Natural, Montevideo, Uruguay;
∗Address for correspondence: 75 Greenmanville Av., Mystic, CT 06355, USA (e-mail: schwindt44@hotmail.com)

Received 1 October 2001; accepted in revised form 24 April 2002

Key words: Argentina, estuarine, exotics, invasions, marine, Patagonia, southwest Atlantic, Uruguay

Abstract

We conducted a comprehensive survey of existing knowledge about exotic marine organisms introduced to the
southwestern Atlantic Ocean, including coastal and shelf areas of Uruguay and Argentina. This domain is equivalent
to the so-called Patagonian Shelf Large Marine Ecosystem, and corresponds to two biogeographic provinces: warm-
temperate (Argentine Province) and cold temperate (Magellanic Province). The search included species that can
be confidently categorized as introduced (31) and cryptogenic species (46). We present a comprehensive picture
of recorded introductions (the first for this region) and some prominent ecological consequences. Most coastal
ecosystems between the La Plata River estuary and central Patagonia have already been modified, or are expected to
be so in the short term. Five recent, human-mediated biological invasions have already had a significant ecological
impact. A barnacle (Balanus glandula) belt has developed on all rocky shores where none was present 30 years
ago, a macro-fouler (Limnoperna fortunei) and a reef-builder (Ficopomatus enigmaticus) have strongly modified
estuarine ecosystems, Pacific oyster (Crassostrea gigas) reefs are expanding in shallow bays at a fast rate, and kelp
(Undaria pinnatifida) is rapidly modifying nearshore benthic communities along the coasts of central Patagonia.
At this point, it is uncertain how many of the cordgrasses (Spartina spp.) found in coastal salt marshes correspond
to exotic forms. Only exposed sandy beaches appear to be free from the pervasive ecological impact of invasion by
exotic species. Poor knowledge of the regional biota makes it difficult to track invasions.

Introduction

The accelerating invasion of coastal marine com-
munities by non-indigenous species is a subject of
much current concern among ecologists, environmen-
talists and managers (Carlton 1996; Carlton and Geller
1993; Ruiz et al. 1999, 2000). Comparative studies
of patterns, a main avenue for progress towards the

understanding of the processes involved in invasibil-
ity and the consequences of invasions, require the
existence of comparable data sets. The scientific and
technical literature is unevenly distributed, as illus-
trated by a sample of references recorded during the
five-year 1997–2001 period by the Aquatic Sciences
and Fisheries Abstracts (ASFA; Figure 1): an over-
whelming majority corresponds to the United States,



116

Figure 1. Geographic distribution of references to non-indigenous marine species in a sample from the literature. The latter (n = 344 references)
was assembled through a search of the Aquatic Science and Fisheries Abstracts (ASFA), using the concatenation of the terms ‘introduced species’
and ‘marine’. Only references that document geographic-specific references on non-indigenous species were retained as part of the sample. The
list provides only an indicator; by no means is it presumed to be comprehensive.

Western Europe and Australia. None to one references
were recovered in the sample for vast expanses of
the World oceans, including most of Latin America,
Africa, the Indian Ocean and the southeast Pacific,
giving the impression that at least some of those regions
are relatively pristine with regards to invasions by non-
indigenous species. As in other cases, this pattern could
be biologically meaningful (reflecting differences in
either availability of propagules or invasibility), or just
indicative of sampling bias (Ruiz et al. 2000). We
explored these hypotheses through a survey of recorded
non-indigenous species in the southwestern Atlantic
(Figure 2), corresponding to the so-called Patagonian
Shelf Large Marine Ecosystem (Sherman 1991; Bisbal
1995), and often regarded as a comparatively pristine
confine of the World Ocean. This applies particularly
to the Patagonian coastal zone (south of 40◦ south lat-
itude (SL); Esteves et al. 2000). This zone is sparsely
populated, with just a handful of relatively small indus-
trialized spots; in most of the watersheds draining to
the sea, there is little to no agricultural development
or intensive animal husbandry. Consequently, the risks
of land-originated chemical pollution are regarded as
relatively minor. Offshore oil-drilling has been con-
sidered, particularly for the Malvinas/Falkland Shelf,
but remains undeveloped. Spills from oil tankers have

occurred, but the risks are small when compared to
the situation in major oil-producing or industrial coun-
tries. The eco-tourism industry thrives, based on large
colonies of marine birds and mammals.

A casual traveler’s glance at most of the Patagonian
coastline may, indeed, confirm those expectations. Yet,
if man-induced changes in the biodiversity tapestry
of coastal seascapes are considered, a closer look at
those regions reveals a very different picture. That
was the aim of the collaborative effort that we under-
took. To this end, we formed an e-discusssion group
of Argentine and Uruguayan scientists within which
information was exchanged and screened in prepara-
tion for a working group meeting that took place con-
currently with the 4th Jornadas Argentinas de Ciencias
del Mar (Puerto Madryn, Argentina, 11–15 September,
2000). The resulting manuscript was circulated among
the members of the group until consensus was reached.
That was the basis for this overview.

While conducting this literature survey, we had two
objectives in mind:
1. To compile all the existing evidence about the intro-

duction of exotics to a region of the World Ocean
where marine biodiversity is very poorly docu-
mented. Moreover, much of the little that is known
is either unpublished or contained in rather cryptic



117

Figure 2. Map of the region considered showing the geographic localities mentioned in the text and latitudinal range of species that have a
significant ecological impact. Dotted lines indicate range interruptions.

sources, normally not available to the international
scientific community. Thus, it is urgent to compile
this information before it is too late.

2. To develop a holistic, ‘big picture’ of how
coastal seascapes of the southwestern Atlantic have

changed as a result of ecologically significant
invasions.

The geographic domain covered by our review corre-
sponds to the coastal zone south of the Brazil/Uruguay
border (the mouth of Chuy Creek, ca. 34◦ SL), down



118

to the southern end of the continent and its adjacen-
cies (including the Malvinas/Falkland Islands, ca. 54◦

SL), a latitudinal range of about 20 degrees. The latter
includes cold-temperate and warm-temperate biotas,
usually assimilated to the Magellanic and Argentine
Biogeographic provinces, respectively (Instituto de
Biologı́a Marina 1964). The transition (in the coastal
zone) is located in northern Patagonia, between ca. 41◦

and 43◦ SL.
The emerging ‘big picture’ showed that the impact

of recent, human-mediated biological invasions has
already had a significant ecological impact. Among the
31 cases identified with certainty as biological inva-
sions, six have had a significant ecological impact.
Two occurred in warm-temperate estuarine environ-
ments, and four along the coastlines of cold-temperate
Patagonia. In this review, we present the results of our
literature survey and discuss priorities for management
and research.

Scope

Criteria for inclusion

This review is based on the personal knowledge of
the members of the working group, and on a careful
screening of published information. Much of the latter
is contained in rather cryptic sources, many of them
not even listed in literature databases like ASFA. We
partitioned the specific records into two sets:
1. Species whose ‘exotic’ status is well documented.
2. Cryptogenic species that are reasonable candidates

for the status of invasive exotics.
The second group requires the specification of criteria
for inclusion; five were considered:
(a) Wide geographic distribution, including ‘cosmo-

politan’ species and species showing biogeograph-
ically incongruous distribution ranges.

(b) Invasive potential indicated by documented exotic
status in other geographic regions.

(c) The species is abundant in the vicinity of presumed
centers of introduction (e.g. commercial harbors),
but rare in (or absent from) the rest of the region.
Special consideration was given to species found
in communities that are associated with anthropic
activities (e.g. fouling communities from harbors).

(d) Life history suggests high, long-distance disper-
sive potential, particularly for rafting on man-made
structures (fouling on the hull of vessels and other

man-made floating/drifting objects), or the ability
to be dispersed with ballast water.

(e) In the case of species with hard parts, absence from
the Quaternary fossil record, which in this region
is rich and has been well documented.

Criteria for exclusions

The following cases were excluded from our review:
(a) Anadromous salmonids, as we have concentrated

on benthic/littoral organisms. Salmonids are the
only documented exotics present in the region that
do not fit the latter condition (Pascual and Orensanz
1996).

(b) Wood-borers, like limnoriid isopods and teredinid
bivalves. While some may have been introduced by
man, these organisms are also dispersed on drifting
woody substrates of natural origin.

(c) Species that, within the study area, are exclusively
associated with floating objects. Many tropical/
subtropical species (e.g. some lepadid barnacles,
amphinomid polychaetes, etc.) are common on
man-made floating objects that, drifting south-
ward along the Brazil Current, reach the coasts of
Uruguay and more frequently northern Argentina,
but also occur on drifting substrates of natural
origin (Barattini and Ureta 1960).

(d) Hydrozoa with a medusa stage, as their often wide
geographic ranges of distribution may be related
to natural dispersion. This is best illustrated with
the Campanulariid generas Clytia, Gonothyraea
and Obelia. Several species have been reported for
the region of interest, some based on the polyp
stage, some on pelagic medusae, and others on
both (Blanco 1964, 1967, 1968, 1976; Blanco
and Morris 1977; Bastida 1971; Vervoort 1972;
Cornelius 1975, 1982; Zamponi 1987; Zamponi
and Genzano 1990; Genzano 1988, 1990, 1995;
Genzano et al. 1991, 1998; Genzano and Zamponi
1992). Most of these are cosmopolitan, but there is
substantial disagreement between authors regard-
ing the definition of species. Other cases are the
bougainvillids Bougainvillia ramosa van Beneden
(1844) (Genzano and Zamponi 1992; Genzano
1995) and Bimeria vestita Wright (1859) (Blanco
1974; Genzano and Zamponi 1992; Genzano
1998).

(e) Invasive species present only on the freshwater
end of estuarine environments, as exemplified by
the corbiculid bivalves Corbicula fluminea Müller



119

(1774) and C. largillierti Philippi (1844), intro-
duced to the La Plata River estuary during the 1970s
(Ituarte 1994). Alternatively, primarily freshwater
species extending into the brackish portion of estu-
aries (e.g. the mytilid bivalve Limnoperna fortunei
Dunker (1857)) were included.

(f) Exotics recorded for Brazil, but not from
Uruguay/Argentina. This criterion is arbitrary, and
was introduced only for practical reasons. North of
the boundary between Brazil and Uruguay (marked
by the mouth of Chuy Creek), the coast is formed
exclusively of exposed sandy beaches over hun-
dreds of kilometers; no exotics have been recorded
for that ecosystem.

General survey of recorded species
introductions into the southwestern Atlantic

The results of our inquiry are summarized in Tables 1
and 2. Table 1 lists all the cases (31 in total) in which
the ‘exotic status’ is reasonably well established. Six
invasions that have had or that are likely to have sig-
nificant ecological effects are discussed in some detail
in the following section. In Table 2, we included cryp-
togenic species, i.e. species that, according to some of
the criteria listed above, are likely candidates to have
been introduced to the region through human-mediated
activities. These amount to 47 cases. Our survey
revealed that crustaceans accounted for ca. one-third of
both cryptogenic (34.7%) and exotic (32.2%) species.
Next were ascidians and bryozoans among the exotics
(respectively with 19.3% and 16%), and annelids and
cnidarians (respectively with 26% and 19.5%) among
the cryptogenics. Most of the exotic/cryptogenic ascid-
ians, bryozoans and cnidarians, as well as some
serpulid polychaetes, are components of the foul-
ing community, and restricted to commercial harbors
(Mar del Plata, Ingeniero White). Of the 31 exotic
species, only 10% are broadly distributed in Argentina,
Uruguay and Brazil, while the majority are concen-
trated in a few locations. The picture is different for
cryptogenics, among which almost half of the species
have a broad range of distribution throughout the south-
western Atlantic. Most of the exotic and cryptogenic
species are concentrated in Buenos Aires Province
(exotics = 79%, cryptogenics = 68%), where major
commercial harbors are located. Finally, the area of
origin is unknown for most of the exotic species; only
29% of them have a well established area of origin,
predominantly the Northeast Pacific and the Far East.

Major sources of uncertainty

Poor knowledge of the biota
The single major source of uncertainty regarding bio-
logical invasions in the southwestern Atlantic is the
poor documentation of the marine biota. This is mini-
mal for some groups, e.g. fungi. The issue of uncertain
status due to inaccurate systematics is well illustrated
by three genera of ubiquitous, small-sized bivalves:
Crenella Brown (1827) (Mytilidae), Lasaea Leach in
Brown (1827) (Lasaeidae) and Hiatella Daudin in Bosc
(1801) (Hiatellidae). All of them have the potential for
long-distance dispersal by vessels, as they tend to live
in association with epibenthic communities, including
fouling communities. In the three cases, cosmopoli-
tan or widespread species have been reported for the
southwestern Atlantic:

1. Crenella (Mytilidae) is in dire need of taxonomic
revision, even if only shell morphology is consid-
ered. The sculpture pattern of the shell in general,
and of the protoconch in particular (which under SEM
can provide valuable characters), have not been com-
paratively described. Crenella divaricata d’Orbigny
(1842) was originally described from Cuba, and later
reported for both coasts of the Americas, from the
Gulf of California to Perú, and from North Carolina to
San Antonio (Argentina). The species may be strictly
tropical (Caribbean); records from the southwestern
Atlantic (Klappenbach 1970; Figueiras and Sicardi
1970b, 1980b; Scarabino 1977; Rios 1985, and records
therein) must be re-evaluated. Melvill and Standen
(1912, later listed by Carcelles and Williamson 1951)
cited the European species C. decussata Montagu
(1808) for sub-antarctic waters, but this record is
most likely incorrect. This species is distributed along
the coasts of the USA, South Japan, the Galapagos
Islands, northern Perú, and North Europe (Coan et al.
2000).

2. Lasaea is an extremely plastic genus, includ-
ing sexually-reproducing species as well as clones of
parthenogens (Ó Foighil and Smith 1995), all mor-
phologically similar to each other. Three ‘cosmo-
politan’ nominal species have been reported for
the southwestern Atlantic: L. adamsoni Gmelin
(1791) (Figueiras and Sicardi 1980b), L. rubra
Montagu (1803) (= L. adamsoni fide Coan et al. 2000)
and L. consanguinea Smith (1879) (Zaixso and
Pastor 1977), but all these specific records are
unsubstantiated.



120

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00
0)

O
ri

gi
na

tin
g

fr
om

ri
ve

rs
fr

om
C

hi
na

an
d

SE
A

si
a;

fr
es

h
an

d
br

ac
ki

sh
w

at
er

L
a

Pl
at

a
R

iv
er

,i
nc

lu
di

ng
es

tu
ar

in
e

po
rt

io
n

(u
p

to
3

pp
t)

G
as

tr
op

od
a,

M
ur

ic
id

ae
R

ap
an

a
ve

no
sa

(V
al

en
ci

en
ne

s
18

46
)

H
ar

di
ng

an
d

M
an

n
(1

99
9)

,
Sc

ar
ab

in
o

et
al

.(
19

99
),

Pa
st

or
in

o
et

al
.(

20
00

)

O
ri

gi
na

tin
g

fr
om

th
e

Se
a

of
Ja

pa
n,

th
e

Y
el

lo
w

Se
a

an
d

th
e

E
as

tC
hi

na
Se

a,
la

te
r

in
tr

od
uc

ed
to

th
e

B
la

ck
Se

a
an

d
C

he
sa

pe
ak

e
B

ay

L
a

Pl
at

a
R

iv
er

es
tu

ar
y,

bo
th

co
as

ts
A

re
co

rd
fr

om
N

ew
Z

ea
la

nd
w

as
ba

se
d

on
em

pt
y

sh
el

ls
(M

ar
sh

al
la

nd
C

ro
sb

y
19

98
)

G
as

tr
op

od
a

(P
ul

m
on

at
a)

,
E

llo
bi

id
ae

M
yo

so
te

ll
a

m
yo

so
ti

s
(D

ra
pa

rn
au

d
18

01
)

Fi
gu

ei
ra

s
an

d
Si

ca
rd

i(
19

74
,a

s
O

va
te

ll
a.

(M
.)

sp
.)

,Z
af

fa
ro

ni
(1

99
4,

as
O

va
te

ll
a

m
.)

N
E

A
tla

nt
ic

,M
ed

ite
rr

an
ea

n,
N

ov
a

Sc
ot

ia
to

C
en

tr
al

A
m

er
ic

a,
B

er
m

ud
a

I,

Pl
ay

a
Po

rt
ez

ue
lo

,M
al

do
na

do
(U

ru
gu

ay
);

em
pt

y
sh

el
ls

pr
es

um
ab

ly
or

ig
in

at
e

fr
om

M
ay

be
na

tiv
e

to
E

ur
op

e



121

Pu
ge

tS
ou

nd
to

C
al

if
or

ni
a,

So
ut

h
A

fr
ic

a,
A

us
tr

al
as

ia
,U

ru
gu

ay

th
e

m
ou

th
of

Po
tr

er
o

C
re

ek
,

w
hi

ch
dr

ai
ns

on
th

at
be

ac
h

C
ir

ri
pe

di
a,

B
al

an
id

ae
B

al
an

us
gl

an
du

la
(D

ar
w

in
18

54
)

Sp
iv

ak
an

d
L’

H
os

te
(1

97
6)

,B
as

tid
a

et
al

.(
19

80
);

N
ew

m
an

an
d

R
os

s
(1

97
6)

,V
al

la
ri

no
an

d
E

lı́a
s

(1
99

7)

N
E

Pa
ci

fic
(A

le
ut

ia
ns

to
B

aj
a

C
al

if
or

ni
a)

;i
nt

ro
du

ce
d

to
th

e
SW

A
tla

nt
ic

Sa
n

C
le

m
en

te
de

lT
uy

ú
to

C
om

od
or

o
R

iv
ad

av
ia

,
A

rg
en

tin
a

(N
ot

‘R
io

de
Ja

ne
ir

o’
,a

s
st

at
ed

by
N

ew
m

an
an

d
R

os
s

(1
97

6)
)

N
at

iv
e

to
th

e
W

es
tC

oa
st

of
N

or
th

A
m

er
ic

a

C
ir

ri
pe

di
a,

B
al

an
id

ae
B

al
an

us
am

ph
it

ri
te

(D
ar

w
in

18
54

)
B

as
tid

a
(1

97
1)

,S
pi

va
k

an
d

L’
H

os
te

(1
97

6)
,N

ew
m

an
an

d
R

os
s

(1
97

6)
,

C
al

ca
gn

o
et

al
.(

19
97

,1
99

8)

C
os

m
op

ol
ita

n
in

w
ar

m
an

d
te

m
pe

ra
te

se
as

In
tr

od
uc

ed
in

hi
st

or
ic

al
tim

es
to

th
e

ha
rb

or
of

M
ar

de
l

Pl
at

a,
w

he
re

it
is

a
co

m
po

ne
nt

of
th

e
fo

ul
in

g
as

se
m

bl
ag

e.
A

ls
o

fo
un

d
in

Q
ue

qu
én

Pr
es

en
ti

n
th

e
sa

m
e

ar
ea

du
ri

ng
th

e
Q

ua
te

rn
ar

y
(P

lio
-P

le
is

to
ce

ne
in

co
re

s
fr

om
A

rg
en

tin
e

Sh
el

f,
37

–4
1

SL
;N

ew
m

an
(1

97
9)

).
M

ay
be

or
ig

in
al

ly
fr

om
th

e
‘N

ea
r

E
as

t’
an

d
th

e
O

ce
an

In
di

an
re

gi
on

(Z
ul

lo
19

66
)

C
ir

ri
pe

di
a,

B
al

an
id

ae
B

al
an

us
tr

ig
on

us
(D

ar
w

in
18

54
)

B
as

tid
a

(1
97

1)
,S

pi
va

k
an

d
L’

H
os

te
(1

97
6)

,N
ew

m
an

an
d

R
os

s
(1

97
6)

,
Z

ul
lo

(1
99

2)

C
os

m
op

ol
ita

n
in

w
ar

m
an

d
w

ar
m

-t
em

pe
ra

te
se

as
In

tr
od

uc
ed

to
th

e
ha

rb
or

of
M

ar
de

lP
la

ta
,w

he
re

it
is

a
co

m
po

ne
nt

of
th

e
fo

ul
in

g
as

se
m

bl
ag

e

Pr
es

um
ab

ly
in

tr
od

uc
ed

in
th

e
A

tla
nt

ic
B

as
in

(Z
ul

lo
19

92
)

A
m

ph
ip

od
a,

C
or

op
hi

da
e

M
on

oc
or

op
hi

um
in

si
di

os
um

(C
ra

w
fo

rd
19

37
)

A
lo

ns
o

(1
99

7,
as

C
or

op
hi

um
i.)

B
ri

tis
h

C
ol

um
bi

a
to

so
ut

he
rn

C
al

if
or

ni
a;

bo
th

si
de

s
of

th
e

A
tla

nt
ic

oc
ea

n;
in

tr
od

uc
ed

to
C

hi
le

,H
aw

ai
ia

nd
th

e
SW

A
tla

nt
ic

B
ue

no
s

A
ir

es
Pr

ov
in

ce
,

es
tu

ar
in

e,
of

te
n

as
so

ci
at

ed
w

ith
F

ic
op

om
at

us
re

ef
s

Pr
es

um
ab

ly
na

tiv
e

to
th

e
N

or
th

A
tla

nt
ic

Is
op

od
a,

L
ig

iid
ae

L
ig

ia
ex

ot
ic

a
(R

ou
x

18
28

)
G

ia
m

bi
ag

i(
19

31
),

C
ar

ce
lle

s
(1

94
4)

(b
ot

h
as

L
ig

yd
a

e.
),

B
ar

at
tin

ia
nd

U
re

ta
(1

96
0)

,R
ec

a
(1

97
2)

,
Sc

ar
ab

in
o

et
al

.(
19

75
,a

s
L

ig
ia

sp
.)

,M
ay

tı́a
an

d
Sc

ar
ab

in
o

(1
97

9)

C
os

m
op

ol
ita

n
al

on
g

w
ar

m
an

d
w

ar
m

-t
em

pe
ra

te
co

as
ts

(e
xc

ep
tE

ur
op

e)
;s

up
ra

tid
al

zo
ne

L
a

Pa
lo

m
a,

M
on

te
vi

de
o,

Q
ue

qu
én

an
d

M
ar

de
lP

la
ta

H
ar

bo
rs

Is
op

od
a,

H
al

op
hi

lo
sc

iid
ae

H
al

op
hi

lo
sc

ia
co

uc
hi

i
(K

in
ah

an
18

58
)

G
ia

m
bi

ag
i(

19
35

,a
s

P
hi

lo
sc

ia
bo

na
ri

en
si

s)
,R

ec
a

(1
97

2)
E

ur
op

e
to

N
W

A
fr

ic
a,

in
tr

od
uc

ed
to

N
or

th
A

m
er

ic
a

an
d

th
e

SW
A

tla
nt

ic

N
ec

oc
he

a
an

d
Sa

n
B

la
s

(A
rg

en
tin

a)
,h

ig
he

r
in

te
rt

id
al

zo
ne

Is
op

od
a,

Id
ot

ei
da

e
Id

ot
ea

m
et

al
li

ca
(B

os
c

18
02

)
W

ag
el

e
(1

99
1)

,B
ra

nd
t(

19
91

),
B

as
tid

a
(1

97
1,

as
I.

ba
lt

ic
a)

W
id

el
y

di
st

ri
bu

te
d,

bu
tn

ot
in

th
e

A
nt

ar
ct

ic
;o

ft
en

pl
an

kt
on

ic

M
ar

de
lP

la
ta

Is
op

od
a,

Id
ot

ei
da

e
Sy

ni
do

te
a

la
ev

id
or

sa
li

s
(M

ie
rs

18
81

)
C

ha
pm

an
an

d
C

ar
lto

n
(1

99
1)

,
G

ia
m

bi
ag

i(
19

22
,a

s
S.

m
ar

pl
at

en
si

s)
,M

añ
é-

G
ar

zó
n

(1
94

6,
as

S.
m

ar
pl

at
en

si
s)

,
M

ar
tin

ez
et

al
.(

19
84

,a
s

S.
br

un
ne

a)

O
ri

gi
na

tin
g

fr
om

Ja
pa

n
an

d
C

hi
na

;i
nt

ro
du

ce
d

to
w

es
te

rn
N

or
th

A
m

er
ic

a
an

d
th

e
SW

A
tla

nt
ic

Il
ha

G
ra

nd
e

(B
ra

zi
l)

to
B

ah
ia

B
la

nc
a

(A
rg

en
tin

a)



122

Ta
bl

e
1.

C
on

tin
ue

d.

M
aj

or
ta

xo
no

m
ic

gr
ou

p
an

d
fa

m
ily

Sp
ec

ie
s

Si
gn

ifi
ca

nt
re

fe
re

nc
es

(p
ri

m
ar

y
re

co
rd

s
fo

r
th

e
re

gi
on

of
in

te
re

st
)

G
en

er
al

ge
og

ra
ph

ic
di

st
ri

bu
tio

n
D

is
tr

ib
ut

io
n

in
th

e
so

ut
hw

es
te

rn
A

tla
nt

ic
C

om
m

en
ts

Is
op

od
a,

Sp
ha

er
om

at
id

ae
Sp

ha
er

om
a

se
rr

at
um

(F
ab

ri
ci

us
17

87
)

R
ou

x
an

d
B

as
tid

a
(1

99
0)

,
K

itt
le

in
(1

99
1)

N
E

A
tla

nt
ic

,f
ro

m
E

ur
op

e
to

N
A

fr
ic

a,
M

ed
ite

rr
an

ea
n

an
d

B
la

ck
Se

a;
S

A
fr

ic
a,

W
A

us
tr

al
ia

,S
W

A
tla

nt
ic

B
ue

no
s

A
ir

es
Pr

ov
in

ce
(A

rg
en

tin
a)

D
ec

ap
od

a,
M

aj
id

ae
P

yr
om

ai
a

tu
be

rc
ul

at
a

(L
oc

ki
ng

to
n

18
77

)
Sc

he
jte

r
et

al
.(

su
bm

itt
ed

)
N

E
Pa

ci
fic

,f
ro

m
th

e
W

es
t

C
oa

st
of

th
e

U
SA

to
Pa

na
m

a
B

ue
no

s
A

ir
es

Pr
ov

in
ce

(A
rg

en
tin

a)
A

ls
o

re
po

rt
ed

as
an

in
va

di
ng

sp
ec

ie
s

in
Ja

pa
n

(C
ar

lto
n

19
87

),
R

io
de

Ja
ne

ir
o

an
d

lit
or

al
do

Pa
ra

ná
,B

ra
zi

l
(d

e
M

el
o

et
al

.1
98

9)

B
ry

oz
oa

,
B

ug
ul

id
ae

B
ug

ul
a

fla
be

ll
at

a
(T

ho
m

ps
on

in
G

ra
y

18
48

)

L
ic

ht
sc

he
in

de
B

as
tid

a
an

d
B

as
tid

a
(1

98
0)

,R
yl

an
d

(1
96

5)
,G

or
do

n
an

d
M

aw
at

ar
i(

19
92

)

C
os

m
op

ol
ita

n
M

ar
de

lP
la

ta
an

d
Pu

er
to

B
el

gr
an

o
ha

rb
or

s
(A

rg
en

tin
a)

,f
ou

lin
g

co
m

m
un

ity

B
ry

oz
oa

,
B

ug
ul

id
ae

B
ug

ul
a

ne
ri

ti
na

(L
in

na
eu

s
17

58
)

H
as

tin
gs

(1
94

3)
,L

óp
ez

-G
ap

pa
(1

97
8)

,L
ic

ht
sc

he
in

de
B

as
tid

a
an

d
B

as
tid

a
(1

98
0)

C
os

m
op

ol
ita

n
Sc

at
te

re
d

re
co

rd
s

fr
om

ha
rb

or
ar

ea
s:

M
ar

de
lP

la
ta

,
Pu

er
to

B
el

gr
an

o,
Pt

.W
ill

ia
m

s
(F

al
kl

an
d

I.
),

as
a

co
m

po
ne

nt
of

th
e

fo
ul

in
g

co
m

m
un

ity

B
ry

oz
oa

,
B

ug
ul

id
ae

B
ug

ul
a

si
m

pl
ex

(H
in

ck
s

18
86

)
R

yl
an

d
(1

96
5)

,L
ic

ht
sc

he
in

de
B

as
tid

a
an

d
B

as
tid

a
(1

98
0)

,
G

or
do

n
an

d
M

aw
at

ar
i(

19
92

)

C
os

m
op

ol
ita

n
Pu

er
to

B
el

gr
an

o,
fo

ul
in

g
co

m
m

un
ity

B
ry

oz
oa

,
B

ug
ul

id
ae

B
ug

ul
a

st
ol

on
if

er
a

(R
yl

an
d

19
60

)
R

yl
an

d
(1

96
5)

,L
ic

ht
sc

he
in

de
B

as
tid

a
an

d
B

as
tid

a
(1

98
0)

,
G

or
do

n
an

d
M

aw
at

ar
i(

19
92

)

C
os

m
op

ol
ita

n
M

ar
de

lP
la

ta
an

d
Pu

er
to

B
el

gr
an

o
ha

rb
or

s,
in

fo
ul

in
g

co
m

m
un

iti
es

B
ry

oz
oa

,
C

he
ilo

po
ri

ni
da

e
C

ry
pt

os
ul

a
pa

ll
as

ia
na

(M
ol

l1
80

3)
R

yl
an

d
(1

96
5)

,L
óp

ez
-G

ap
pa

(1
97

8)
,L

ic
ht

sc
he

in
de

B
as

tid
a

an
d

B
as

tid
a

(1
98

0)
,G

or
do

n
an

d
M

aw
at

ar
i(

19
92

)

C
os

m
op

ol
ita

n
M

ar
de

lP
la

ta
,Q

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123

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124

Table 2. Cryptogenic species.

Major taxonomic
group and family

Species Significant references
(primary records for the
region of interest)

General geographic
distribution

Distribution in the
southwestern Atlantic

Porifera, Clionidae Cliona celata (Grant
1826)

Cuartas (1991), Genzano
et al. (1991)

Cosmopolitan Rio de Janeiro to Mar del
Plata, 0–100 m

Porifera,
Halichondriidae

Halichondria panicea
(Pallas 1766)

Burton (1934), Cuartas
(1991)

Cosmopolitan Magellanic to 37◦ S on
the Atlantic

Porifera,
Hymeniacidoniidae

Hymeniacidon hirta
(Topsent 1889)

Burton (1940, as Stylohalina),
Berroa-Belén (1989)

Gulf of Mexico, Gulf of
Guinea, SW Atlantic

Uruguay to San Jorge
Gulf (Argentina)

Porifera,
Hymeniacidoniidae

Hymeniacidon
sanguinea (Grant
1927)

Burton (1940), Cuartas and
Excoffon (1993)

Cosmopolitan La Paloma; Mar del Plata,
where it is the
predominant sponge
species in the rocky
intertidal

Hydrozoa,
Sertulariidae

Dynamena cornicina
(McCrady 1858)

Genzano and Zamponi (1992) Red Sea, Mediterranean,
North Atlantic S to
Caribbean

Brazil to Mar del Plata

Hydrozoa,
Sertulariidae

Sertularella
mediterranea
(Hartlaub 1901)

Genzano (1990, 1998),
Genzano and Zamponi (1992)

Worldwide scattered
records

Apparently only in Mar
del Plata (Argentina)

Hydrozoa,
Plumulariidae

Plumularia setacea
(Ellis 1755)

Blanco (1966, 1976),
Genzano et al. (1991),
Genzano and Zamponi
(1992), Genzano (1998)

Widely distributed in
warm and temperate seas
(absent from polar seas)

Magellanic region to
Mar del Plata

Hydrozoa,
Hebellidae

Hebella scandens
(Bale 1888)

Genzano and Zamponi (1992) Cosmopolitan Mar del Plata

Hydrozoa,
Tubulariidae

Tubularia crocea
(Agassiz 1862)
Status may needs
revision (Petersen
1990)

Bastida (1971), Zamponi and
Correa (1988), Genzano
et al. (1991), Genzano and
Zamponi (1992), Genzano
(1998)

Cosmopolitan in warm
and temperate seas

Magellanic and Argentine
provinces. Records from
the southwestern
Atlantic are in need of
review

Hydrozoa, Claviidae Rhizogetum nudum
(Broch 1909)

Genzano and Zamponi (1992) Worldwide scattered
records

Mar del Plata

Actiniaria,
Boloceroidiidae

Boloceroides
mcmurrichi
Kwietniewski, 1899

Zamponi (1977) Widely distributed in the
Indopacific

Near Mar del Plata
(Argentina), intertidal
limestone platform

Actiniaria,
Actiniidae

Aulactinia reynaudi
(Milne-Edwards
1857)

Zamponi (1977, as
Bunodactis r.), Acuña and
Zamponi (1996, 1997),
Acuña (1997)

West and South Africa Mar del Plata
(Argentina),

intertidal, rocky shores

Actiniaria,
Actiniidae

Oulactis muscosa
(Dana 1849)

Zamponi (1977), Excoffon
and Zamponi (1995), Acuña
and Zamponi (1997)

Australia, Puerto Rico,
Argentina

Mar del Plata
(Argentina),

rocky shores

Polychaeta,
Nereidae

Neanthes succinea
(Frey and Leuckart
1847)

Dei Cas and Mañé-Garzón
(1973), Orensanz and
Gianuca (1974)

Widely distributed in
warm and temperate seas;
common in estuarine
environments. Presumably
native to the North Atlantic

La Plata River estuary,
Mar Chiquita coastal
lagoon

Polychaeta,
Hesionidae

Syllidia armata
(Quatrefages 1865)

Orensanz (pers. obs.) West Atlantic, from Ireland
to South Africa

Mar del Plata Harbor

Polychaeta,
Syllidae

Syllis gracilis
(Grube 1840)

Orensanz (pers. obs.) Worldwide in warm and
temperate seas

Mar del Plata (rocky
intertidal and fouling
community)



125

Table 2. Continued.

Major taxonomic
group and family

Species Significant references
(primary records for the
region of interest)

General geographic
distribution

Distribution in the
southwestern Atlantic

Polychaeta,
Dorvilleidae

Schistomeringos
rudolphi (Delle
Chiaje 1828)

Orensanz (1974, as
Stauronereis r.)

Cosmopolitan in temperate
and tropical seas, in
shallow water

Uruguay to San Matias
Gulf; most abundant in
polluted environments of
Mar del Platar harbor
and its adjacencies

Polychaeta,
Iphitimidae

Ophryotrocha
‘puerilis’, auctorum

Orensanz (1990) Scattered worldwide
localities, often in aquaria

Mar del Plata (Argentina),
in an aquarium

Polychaeta,
Spionidae

Boccardia
polybranchia
(Haswell 1885)

Blake (1983) Widespread along warm
and temperate coastlines,
mostly in the southern
Hemisphere

Widespread throughout
the region, usually in the
high intertidal zone

Polychaeta,
Spionidae

Polydora ciliata
(Johnston 1838)

Blake (1983) Europe, S Africa,
SW Atlantic

Uruguay to the Falkland I.

Polychaeta,
Spionidae

Polydora cornuta
(Bosc 1802)a

Orensanz and Estivariz
(1972, as P. ligni), Blake and
Maciolek (1987), Blake (1983)

New England to Florida,
California, SW Atlantic;
intertidal and estuarine

Mar Chiquita coastal
lagoon, associated with
colonies of Ficopomatus

Polychaeta,
Spionidae

Polydora flava
(Claparede 1870)

Blake (1983) Widely scattered locations
in temperate and
warm seas

Uruguay to Puerto
Madryn

Polychaeta,
Spionidae

Polydora socialis
(Schmarda 1861)

Blake (1983) Both coasts of the Americas,
Australia and
New Zealand

Mar del Plata to San Jose
Gulf

Polychaeta,
Spirorbidae

Neodexiospira
mannarensis
(Pillai 1970)

Knight-Jones and
Knight-Jones (1991)

Widespread in warm and
temperate seas

Puerto Quequén

Polychaeta,
Spirorbidae

Simplaria
pseudomilitaris
(Thiriot-Quievreux
1965)

Knight-Jones and
Knight-Jones (1991)

Widespread in warm and
temperate seas

Puerto Quequén

Bivalvia, Mytilidae Perna perna
(Linnaeus 1758)b

Figueiras and Sicardi (1968,
1980a, b), Bernard (1983),
Rios (1985)

Venezuela to Uruguay;
rocky shores

Cirripedia,
Balanidae

Balanus pallidus
(Darwin 1854)

Newman and Ross (1976) Scattered records from
tropical and subtropical
coasts

Argentine Patagonia

Cirripedia,
Balanidae

Balanus improvisus
(Darwin 1854)

Carcelles (1944, as
B. i. communis), Spivak and
L’Hoste (1976), Newman
and Ross (1976)

East Coast of the Americas;
West Coast of Africa;
Mediterranean, Black and
Red Seas; Washington to
San Francisco; Japan;
Australia; SW Atlantic

Estuarine environments:
Montevideo, Punta Indio,
Mar Chiquita coastal
lagoon; also Mar del Plata
Harbor. Originally
described by Darwin
(1854) for Montevideo
and Patagonia

Amphipoda,
Talitridae

Orchestia gammarella
(Pallas 1766)

Alonso (1986) North Atlantic, from
Iceland to Canary I. and to
Maine, Mediterranean;
SW Africa, SW Atlantic

Puerto Deseado area
(Argentine Patagonia)

Amphipoda,
Talitridae

Orchestia
mediterranea
(Costa 1857)

Escofet (1973) Mediterranean, North
Atlantic (France, England,
Wales, Ireland)

Mar del Plata region



126

Table 2. Continued.

Major taxonomic
group and family

Species Significant references
(primary records for the
region of interest)

General geographic
distribution

Distribution in the
southwestern Atlantic

Amphipoda,
Talitridae

Platorchestia
platensis
(Kroyer 1845)

Bousfield (1973), Escofet
(1973) (all as Orchestia sp.)

Nearly cosmopolitan along
tropical-temperate
coastlines

Montevideo and Mar del
Plata

Amphipoda,
Melitidae

Melita palmata
(Montagu 1804)

Escofet (1973; as Melita sp.),
Alonso (1986), Alonso
(1997)

NE Atlantic from British I.
to Senegal, Mediterranean;
SW Atlantic

Mar del Plata area to
Golfo Nuevo, intertidal
and estuarine, associated
with Ficopomatus reefs

Amphipoda,
Melitidae

Maera grossimana
(Montagu 1808)

Wakabara et al. (1982),
Lincoln (1979), Escofet
(1973, as Maera sp.)

Mediterranean and
North Atlantic

Amphipoda,
Ampithoidae

Ampithoe valida
(Smith 1873)

Alonso (1986), Alonso et al.
(1996), Alonso (1997)

NW Atlantic, NE Pacific
(California and Oregon),
Japan, SW Atlantic

Rawson to Puerto
Quequén, low intertidal
and shallow subtidal

Amphipoda,
Ampithoidae

Cymadusa filosa
(Savigny 1816)

Escofet (1973, as
Cymadusa sp.), Alonso
(1986)

Widely distributed in warm
and temperate seas

Mar del Plata to San
Matı́as Gulf; low
intertidal, among algae

Amphipoda,
Caprellidae

Caprella equilibra
(Say 1818)

McCain (1968), McCain and
Gray (1971)

Almost cosmopolitan,
0–3000 m

Chile and Argentina,
interrupted in the
Magellanic region

Amphipoda,
Caprellidae

Caprella penantis
(Leach 1814)

McCain (1968), McCain and
Gray (1971)

Almost cosmopolitan Southern South America

Mysidacea,
Mysidae

Neomysis americana
(S.I. Smith 1873)

González (1974), Hoffmeyer
(1990)

NW Atlantic, from the Gulf
of St. Lawrence (Canada)
to Florida (USA);
SW Atlantic

Uruguay to San Blas
(Argentina), in shallow
bays and estuaries

Tanaidacea,
Tanaidae

Sinelobus stanfordi
(Richardson 1901)

Giambiagi (1923),
Mañé-Garzón, 1943) (both as
Tanais fkuviatilis),
Sieg (1983a, b)

Tropical and warm
temperate coasts, often
estuarine; 0–20 m

La Plata River estuary

Tanaidacea,
Tanaidae

Tanais dulongii
(Audouin 1826)

Giambiagi (1922, 1923, as
T. gallardoi), Sieg (1983a, b)

Scattered regions along
temperate coasts

Puerto Madryn

Decapoda,
Panopeidae

Panopeus
meridionalis
(Williams 1983)

Williams (1983), Williams and
Boschi (1990), Boschi et al.
(1992)

Montevideo (Uruguay),
Mar del Plata and Mar
Chiquita coastal lagoon
(Argentina); intertidal

Decapoda,
Grapsidae

Pachygrapsus
transversus
(Gibbes 1850)

Williams (1984), Zolessi and
Philippi (1995)

North Carolina to Uruguay;
Bermuda I.; California to
Perú, Galápagos I.;
Mediterranean Sea to
N Angola. Intertidal

Uruguay

Bryozoa, Crisiidae Crisia eburnea
(Linnaeus 1758)

Borg (1944), Lichtschein de
Bastida and Bastida (1980)

Cosmopolitan Tierra del Fuego; fouling
community of Puerto
Belgrano

Bryozoa,
Vesiculariidae

Bowerbankia gracilis
(Leidy 1855)c

Ryland (1965), Amor and
Pallares (1965), Bastida
(1971), López Gappa (1978),
Lichtschein de Bastida and
Bastida (1980), López Gappa
et al. (1982), Gordon and
Mawatari (1992)

Almost cosmopolitan, in
fouling communities

Puerto Deseado, Puerto
Belgrano, Mar del Plata
(fouling community)



127

Table 2. Continued.

Major taxonomic
group and family

Species Significant references
(primary records for the
region of interest)

General geographic
distribution

Distribution in the
southwestern Atlantic

Bryozoa,
Membraniporidae

Conopeum
reticulum

(Linnaeus 1767)

Marcus (1938), Ryland (1965),
Lichtschein de Bastida and
Bastida (1980), Bremec
(1989)

Cosmopolitan in fouling
communities

Puerto Belgrano, Bahia
Blanca, Puerto Deseado;
common in several
localities of Buenos
Aires Province (López
Gappa, pers. obs.)

Bryozoa,
Scrupariidae

Scruparia ambigua
(d’Orbigny 1847)

Hastings (1943), Amor and
Pallares (1965), López Gappa
(1978), Hayward (1995),
Lichtschein de Bastida and
Bastida (1980), López Gappa
and Lichtschein (1990)

NW Atlantic and adjacent
seas, Magellanic region,
Amsterdam I., Australia,
Nueva Zelandia,
California, Galapagos I.
Often associated with
algae; frequent in fouling
communities of harbors

Magellanic, N to Pto.
Belgrano. Originally
described for the Falkland I.
by d’Orbigny (1847), as an
epibiont of algae. Jullien
(1888) recorded it in the
19th century from a remote,
presumably pristine region
(Orange Bay, Hoste I.).
Several locations over the
Patagonian Shelf (Hastings
1943; López Gappa and
Lichtschein 1990)

aSeparation of sibling species in the ‘ligni’ complex may be impossible on the basis of morphological characters alone (Rice 1991).
bThe genus Crisia presents serious taxonomic difficulties. Identification of species is almost impossible in the absence of gonozoids. Lichtschein
de Bastida and Bastida (1980) did not illustrate their materials. Other species of the genus have been recorded for the SW Atlantic, including
C. patagonica (d’Orbigny 1847) described for Bahı́a Rosas and recorded by Bremec (1989) for Monte Hermoso. The specimens reported by
Lichtschein de Bastida and Bastida (1980) could well correspond to the latter.
cJullien (1888) reported three species of Bowerbankia for Orange Bay (Hoste I., Magellanic region), but all were incompletely described. The
taxonomic status of those records is still unresolved.

3. Records of Hiatella from the southwestern
Atlantic have been assigned to two widely spread
nominal morpho-species: H. arctica Linnaeus (1767)
(Figueiras and Sicardi 1980b; Rios 1985) and H. solida
G. B. Sowerby I (1834) (Richards and Craig 1963;
Dell 1964; Figueiras and Sicardi 1970b). Preliminary
data (D. Luzzatto and P. Penchaszadeh, pers. obs.)
suggest that members of a local population mature at
a very small size as compared with H. arctica from
the Northern Hemisphere, a feature that could suggest
the existence of an endemic form. The taxonomic sta-
tus of records from the southwestern Atlantic requires
clarification.

Cosmopolitans: real cases, misidentification,
or man-mediated introductions?

According to Inclusion Criterion (a) (listed ear-
lier), species with wide or incongruous geographic
distribution are suspicious of being exotic invaders.
These fall generally within the definition of ‘crypto-
genic species’, i.e. those that are ‘not demonstrably
native or introduced’ (Carlton 1996). In these cases,

three general hypotheses usually compete to explain
their origin:
(H1) The species is truly cosmopolitan, its wide

geographic distribution preceding man-mediated
dispersal.

(H2) What is seen as a ‘cosmopolitan’ morphospecies
really corresponds to a cluster of genetically dis-
tinct species, each of them with a geographically
restricted range of distribution.

(H3) The current ‘cosmopolitan’ range of distribution
is the result of un-documented man-mediated
dispersal.

Unraveling these cases requires the concatenation
of systematic, genetic, ecological and historical evi-
dence. It is often the case that complex patterns can
be explained by a mixture of the three hypotheses, as
has been illustrated by the blue mussels (Mytilus spp.;
Hilbish et al. 2000).

Natural fluctuations of geographic range
The southern limit of the distribution range of some
subtropical species in the southwestern Atlantic has
changed in historical times. Natural range expansions,



128

if not interpreted correctly, could give the false impres-
sion of recent introductions. One well-documented
example is that of the beach clam Donax hanleyanus
Philippi (1847), which was absent from exposed
sandy beaches south of La Plata River during the
1950s and 1960s, although its presence during the
Holocene is attested by the fossil record (von Ihering
1907; Farinati 1985). It was first recorded as liv-
ing there by Castellanos and Fernández (1965), and
afterwards populations exploded (Penchaszadeh and
Olivier 1975). The ocypodid Uca (Celuca) uruguayen-
sis Nobili (1901), was common in the Mar Chiquita
Lagoon during the 1960s (Olivier et al. 1972a), but
disappeared for ca. two decades until it reappeared
during the 1990s (Spivak et al. 1991). Pelagic larvae of
species with established populations north of La Plata
River estuary are occasionally transported southward,
and settle in northern Argentina. Examples are pro-
vided by ‘extralimital records’ of the mole crab Emerita
brasiliensis Schmitt (1935) (Scelzo and Boschi 1973),
and the portunid crabs Callinectes sapidus acuti-
dens Rathbun (1896) (Ringuelet 1963), and Arenaeus
cribarius Lamarck (1818) (Sczelzo 2001).

The case of the mytilid mussel Perna perna Linnaeus
(1758) is more complicated. Its recent range of dis-
tribution extends along the tropical and subtropical
coasts of the western Atlantic; it was already reported
for Santa Catarina (southeast Brazil) by von Ihering
(1897, 1900), but first found in Uruguay during the
1950s (Barattini and Ureta 1960; Klappenbach 1965,
p. 335; Amaro 1965). The species is not represented
in Quaternary deposits. Some populations were heav-
ily exploited in the intertidal zone during the 1970s.
Its abundance declined during the 1980s, but strong
recruitment was detected again during the late 1990s
(Scarabino, pers. obs.). There is evidence that man
contributed to the dispersion of this species during the
19th century, or even earlier (Carlton 1985). Thus,
its appearance in Uruguay may reflect a mixture of
human-mediated and natural episodes.

Transformation of a biota: introductions that
have already had a significant or potential
ecological impact

Ficopomatus enigmaticus
Ficopomatus (= Mercierella) enigmaticus Fauvel
(1923), a serpulid polychaete, is a calcareous
reef-builder distributed in brackish waters of tem-
perate zones throughout warm-temperate regions

(ten Hove and Weerdenburg 1978). Presumably orig-
inating from Australia (Allen 1953) and originally
described from France, it was first observed in the
southwest Atlantic in a freshwater creek in Uruguay
(Arroyo Las Brujas; Monro 1938) and in an Argentine
estuary (Quequén River; Rioja 1943). Along the coasts
of Uruguay, it has been reported for the Bay of Mon-
tevideo (Scarabino et al. 1975), Valizas Creek (Nion
1979) and Garzón coastal lagoon (J. M. Orensanz, pers.
obs.), but has not been observed in the Lagoa dos
Patos, an extensive estuarine ecosystem in southern
Brazil (Capitoli et al. 1978). It had been long estab-
lished in the Mar Chiquita coastal lagoon (46 km2,
Figure 1) in 1964, when Olivier et al. (1972a, b)
conducted an ecological survey. However, there is no
evidence of the presence of its conspicuous colonies
in Holocene deposits of the Querandinean Ingression,
a shallow brackish sea with well-documented fossil
deposits (Orensanz and Estivariz 1972). This indicates
that it is an exotic invader, as is the case over much of
its geographic range.

The development of reefs is most spectacular in
the Mar Chiquita coastal lagoon (Fasano et al. 1982),
where they dot hundreds of hectares Figures 3A–B).
Regions where reefs proliferate are usually embay-
ments where water flow is multidirectional, domi-
nated by wind (E. Schwindt, pers. obs.), and reefs
have an approximately circular shape (Figure 3). The
size of the reefs is variable (up to 7 m in diameter
and 0.5 m in height; Schwindt 2001) with maximum
height depending on water level (Obenat and Pezzani
1994). It is common to find pairs of reefs that have
coalesced (Obenat and Pezzani 1989; Schwindt and
Iribarne 1998). When water flow is unidirectional (i.e.
in channels and creeks), the shape of reefs is generally
elongated, parallel to current direction. The abundance
of reefs decreases towards the mouth of the lagoon
(where salinity increases).

Within a reef, live individuals are found around
the edges (Figure 3D), where larval settlement occurs
between the calcareous tubes (Obenat and Pezzani
1994). Recruitment also takes place on empty mollus-
can shells (Schwindt and Iribarne 2000), bottles, rocks,
pillars, bones, and dislodged reef fragments (Obenat
and Pezzani 1994; Schwindt 2001). The accumula-
tion of sediment trapped inside the reef results in the
death of the oldest individuals (Keene 1980; Obenat
and Pezzani 1989). The maximum recorded length is
55 mm (Obenat and Pezzani 1989). In Mar Chiquita,
it is an annual iteroparous whose females may release



129

Figure 3. A–D: Ficopomatus reefs in Mar Chiquita coastal lagoon. A: Aerial view, B: aerial view at closer range, singling out a reef, C:
reef at close range, D: detail of the tubes (scale bar: 5 cm). E–G: Crassostrea gigas in San Blas Bay. E: general view of the rocky intertidal,
F–G: close-ups. The intertidal mussels are Brachidontes rodriguezii and Mytilus edulis platensis (both mytilids).



130

1–2 batches of small eggs per reproductive period; lar-
vae are planktothrophic (Obenat and Pezzani 1994).
There are two settlement periods: March–April and
November–December (Obenat and Pezzani 1994).

Ficopomatus reefs provide the structural matrix for a
complex and diversified community. The tubes, which
are white when initially secreted, are steadily covered
by bryozoans, green algae and diatoms as they age
(Obenat and Pezzani 1989). The reefs provide refuge to
numerous organisms, including molluscs, other poly-
chaetes, amphipods and crabs (Orensanz and Estivariz
1972; Schwindt and Iribarne 2000). Among the lat-
ter, there is a significant increase in the abundance of
juveniles and adults of the grapsid Cyrtograpsus alti-
manus Rathbun (1915) (E. Spivak, pers. obs.), as well
as juveniles (4–7 mm) of the congeneric C. angulatus
Dana (1851) (Spivak et al. 1994). The only preda-
tor reported is a reef-inhabiting gobiid fish (Gobio-
soma parri Ginsburg (1933); Olivier et al. 1972b),
a rather infrequent species (Schwindt, pers. obs.).
Several aquatic birds (e.g. swans, ducks) use the reefs
as resting sites, increasing the local concentration of
nutrients (Schwindt and Iribarne 1998).

Reefs have affected sedimentation in their adjacen-
cies as well as the biota of the flats. Reef structures are
efficient traps for sediments that would otherwise be
transported out of the lagoon (Schwindt 2001). They
serve as a refuge for adult Cyrtograpsus angulatus,
whose abundance is positively correlated with reef size
(Schwindt and Iribarne 2000). Crabs, in turn, have a
negative effect on the density of polychaetes inhabiting
the adjacent mudflats. Density of Heteromastus cf. sim-
ilis Southern (1921) and Laeonereis acuta Treadwell
(1923) decreases, while density of Nephtys fluviatilis
Monro (1937), increases close to the reefs (Schwindt
and Iribarne 2000). Among the meiofaunal organisms
inhabiting the top 3 cm of the sediments, only the abun-
dance of ostracods is affected by crabs taking refuge
under the reefs (Schwindt 2001).

The introduction and subsequent spread of
Ficopomatus enigmaticus in Mar Chiquita resulted in
dramatic, large-scale modification of the lagoon’s eco-
logical and sedimentary dynamics, as well as in con-
strains to recreational navigation. Similar phenomena
have been reported for other coastal lagoons (Fornós
et al. 1997).

Limnoperna fortunei
Three important commercial harbors (Buenos Aires,
Montevideo and La Plata) make the La Plata River

estuary (Figure 1) a likely entry port for invasive
exotics. Limnoperna fortunei, the ‘golden mussel’, was
first detected in 1991 in Balneario Bagliardi, on the
southern coast of the estuary (Pastorino et al. 1993).
Darrigran (1995) predicted that its introduction could
create serious environmental problems. This was the
first warning regarding freshwater macrofouling in the
Neotropics, where that problem had been restricted to
marine and brackish water habitats.

The golden mussel, originating from river systems
in China and southeast Asia, invaded Hong Kong in
1965, then Japan and Taiwan in the 1990s (Darrigran
2000). Darrigran and Pastorino (1995a,b) hypothesized
that the species reached the La Plata River system
accidentally, presumably from ballast water discarded
from merchant vessels. Like other mytilid mussels,
it is epifaunal, adhering to hard substrates, natural
(logs, aquatic vegetation, compacted silt-sandy bot-
toms) as well as artificial (docks, pipes, etc.). Its
wide environmental tolerance enables its rapid dis-
persion. Between 1991 and 2000, it invaded three
major rivers in the La Plata Basin (La Plata, Paraná
and Paraguay Rivers). It has spread at an average
rate of 240 km year−1. Its rate of population growth
has been high in a region where it has no competi-
tors. In 1991, when first detected, density was 4 to
5 mussels m−2 on rocks of Balneario Bagliardi (where
its presence was first detected). Average density (on
the same rocks) exploded to 30,000 mussels m−2 in
1992, and 82,000 mussels m−2 in 1993; presently, it
is in the order of 150,000 mussels m−2 (Darrigran et al.
1999).

The economical impact of the invasion, which
affects both natural communities and the human
environment, parallels the case of the zebra mus-
sel (Dreissena polymorpha Pallas (1771)) in North
America (Darrigran and Ezcurra de Drago 2000).
Significant effects include the clogging of pipes and fil-
ters (Figures 4B and D), changes in flow at the boundary
layer, accumulation of empty shells, and the contam-
ination of water coming through pipes due to mussel
mass mortality. These problems have been observed in
the water intake of water treating plants of La Plata
City (Darrigran and Pastorino 1995a, b) and Esquina,
as well as in the water intake of industrial and power-
generating plants (Darrigran 1997a, b; Codina et al.
1999). Operating costs increase due to lowered pump
efficiency, tube corrosion due to the enhanced prolif-
eration of bacteria and fungi, and service interruptions
for the cleansing and changing of filters.



131

Ecologically, the invasion by L. fortunei has had an
impact on native communities. It has become a com-
ponent in the diet of several fishes (Montalto et al.
1999), and even changed the diet of a native species
(Penchaszadeh et al. 2000). In Bagliardi Beach (where
it was first recorded), two gastropds that were com-
monly found have vanished: Chilina fluminea Maton
(1809) has no longer been found, while Gundlachia
concentrica d’Orbigny (1835) has become very rare.
In contrast, other species appeared in the modified
habitats, including eight species of oligochaetes, one
aphanoneuran, eight leeches, and crustacea and insects
not observed before (Darrigran et al. 1998). Finally,
native bivalves (e.g. Anodontites trapesialis Lamarck
(1819)) and A. tenebricosus Lea (1834) are smothered
by L. fortunei, in a way similar to what has been
described for Dreissena polymorpha’s smothering of
native unionid mussels in North America (Figures 4A
and C). According to Scarabino and Verde (1995), it
may have also displaced Mytella charruana d’Orbigny
(1842) (an indigenous mytilid) on the Uruguayan coast
of the estuary.

Crassostrea gigas
Crassostrea gigas Thunberg (1795), the ‘Pacific
oyster’, is a relatively large species originating from
Japan, where several races or morphotypes are found
in different regions. Best known among these varieties
are the Hokkaido, Miyagi, Hiroshima and Kumamoto.
This is a fast growing species that tolerates a wide range
of environmental conditions (Shatkin et al. 1997),
which has resulted in its wide spread over warm
and temperate seas following intentional or acciden-
tal introductions. In South America, it has been intro-
duced to Chile and Perú on the Pacific, and Brazil and
Argentina on the Atlantic. Presently, the Pacific oyster
constitutes 98% of the World’s oyster production (FAO
1999).

Its introduction to Argentina resulted from an uncon-
trolled event in 1982, when a fisheries firm (API)
brought ca. 500 specimens to San Blas Bay (40◦32′ S;
62◦18′ W, Figure 1) with the intention of starting an
oyster-culture operation. An inquiry conducted by one
of us (M. Pascual) indicates that the specimens were 4
bought in Buenos Aires, where ca. 40 tons year−1 were
imported that year for local consumption. According
to a local informer (Gianni, pers. comm.), the trans-
planted lot had originated in Coquimbo (Chile), where
the Pacific oyster was cultivated experimentally at the
Universidad Católica del Norte. The San Blas operation

was conducted by a countryman of Korean origin who
had acquired some basic knowledge of oyster-culture
during his childhood. The initial culture operation
was interrupted after a few months, and the oysters
abandoned.

In 1987, local folks began finding large adult oys-
ters (up to 35 cm long) with juveniles attached to their
shells. Thus, five years after the introduction, there
was a small population of reproductively active adults.
By 1995, there was incipient colonization of intertidal
limestone terraces at Los Pocitos, a site located 25 km
from San Blas. Average oyster density in Los Pocitos
was ca. 2 m−2 in 1995 and 3 m−2 in 1996 (M. Pascual,
pers. obs.); new recruits were still scarce.

Settlement increased explosively between 1998 and
2000; a density of up to 120 recruits m−2 was observed
in Los Pocitos in 1999. North of San Blas lays Bahı́a
Anegada, an extensive system of ca. 2830 km2 of tidal
flats, salt marshes and flat islands. Although there
has not been a systematic survey of this region, scat-
tered observations indicate that the Pacific oyster is
widespread, colonizing preferentially the middle and
low intertidal zone of limestone outcrops. Spat is also
found attached to boulders, empty shells, the basal
portion of Spartina, and to the shells of a native
small mussel (Brachidontes rodriguezii d’Orbigny
(1842)) (Figures 3E–G) that typically forms mono-
cultures along the rocky shores of the southwestern
Atlantic. The spatial architecture of intertidal commu-
nities has become more complex than it was before
the introduction, with increased availability of refuge
space. A dramatic change is underway, as oyster reefs
have started to develop.

In recent years, a hatchery located in San Anto-
nio Oeste (the only one in the region, Figure 1)
has began producing Pacific oyster ‘seed’. Oysters
have been transplanted for experimental aquaculture to
Las Toninas (Buenos Aires Province, 1998 and 1999,
Figure 1), Rı́o Gallegos and San Julián (southern Santa
Cruz Province, 1998), and Caleta Olivia (northern
Santa Cruz Province, 1999, Figure 1). So far no inva-
sion of natural ecosystems has been detected at these
locations.

Balanus glandula Darwin (1854)
Early descriptions of the intertidal rocky shores of
the southwestern Atlantic (Olivier et al. 1966a, b;
Penchaszadeh 1973) showed a zonation pattern unusual
in temperate coasts: the absence of a barnacle belt. In
hard substrates, whether sheltered or exposed, the small



132

Figure 4. A–D: Limnoperna fortunei in La Plata River. A: mussels overgrowing a native clam Anodontites trapesialis (scale bar: 1 cm). B:
mussels clogging a macrofouling sampler (scale bar: 5 cm). C: mussels overgrowing Corbicula fluminea (scale bar: 1 cm). D: Same as B, close
up (scale bar: 2 cm). E–F: Belt of the barnacle Balanus glandula on the rocky shore of Mar del Plata. A: general view, B: detail of the contact
zone with Brachidontes rodriguezii.



133

mytilids Brachidontes rodriguezii and Perumytilus
purpuratus Lamarck (1819) (the first, predominant
towards the northern part of the region, the second
towards the south) monopolized space in most of the
intertidal zone.

During the 1960s, an invasion by Balanus amphitrite
Darwin (1854), was observed in the harbor of
Mar del Plata (Bastida 1971, Figure 1), where it
became dominant in the intertidal zone, alternating
with degraded patches of the B. rodriguezii-dominated
native community. By the end of the decade a second
immigrant barnacle species, Balanus glandula, was
detected on experimental plates within the harbor of
Mar del Plata (Spivak and L’Hoste 1976; Bastida et al.
1980) and on adjacent rocky shores (Figures 4E–F).
This second invader is native to the northeast Pacific,
from Baja California to Alaska (Foster et al. 1991),
where it is a prominent member of the high intertidal
community along rocky shores.

In the southwestern Atlantic, B. glandula is now
well established along all rocky shores between 37◦ S
and 47◦ S. A record from Rio de Janeiro by Newman
and Ross (1976), based on a personal communication
by E. Spivak is incorrect; the communication referred
instead to Mar del Plata. The interaction between
B. glandula and the native intertidal mytilids appears to
be complex, differing between sheltered and exposed
habitats. In the latter, it tends to occupy the high
intertidal zone (above the natural limit of the mussel
belt; Figures 4E–F) and areas physically disturbed by
episodic storms or sediment transport. The spread of
this species may have been favored by winter repro-
duction allowing the occupation of bare substrate cre-
ated by autumn-winter storms, and by the absence of
invertebrate predators in the intertidal zone (at least
towards the northern part of its new range) (Vallarino
and Elı́as 1997; Elı́as and Vallarino 2001). Whatever
the details of the pattern or the mechanisms involved,
the rocky shores of the southwestern Atlantic now
exhibit a well-developed barnacle belt over a range of
ten degrees of latitude.

Undaria pinnatifida (Harvey) Suringar (1872)
Undaria pinnatifida is a laminarian kelp native to
temperate coasts of Japan, Korea and parts of
China (Akiyama and Kurogi 1982). It is an invasive
species in France (Perez et al. 1981), the Mediter-
ranean (Boudouresque et al. 1985), New Zealand
(Hay and Luckens 1987), on the east coast of
Tasmania (Sanderson 1990), Galicia and Asturias

(Santiago Caamaño et al. 1990; Salinas et al. 1996),
northern Argentine Patagonia (Piriz and Casas 1994),
the Venice lagoon (Curiel et al. 1994), the south
coast of England (Fletcher and Manfredi 1995),
Australia (Campbell and Burridge 1998), Belgium and
The Netherlands (Dumoulin and De Blauwe 1999;
Stegenga 1999).

It was recorded for the first time in Argentina in
December 1992 (Piriz and Casas 1994). The first plants
were found attached to wharf piles in Puerto Madryn
(Figure 1), suggesting that the most likely vector of
introduction was the ballast water or fouling of cargo
ships or fishing vessels arriving to Nuevo Gulf from
Japan or Korea. About eight years later, its range has
expanded 20 km to the north and 18 km to the south
of the introduction site, occupying both artificial and
natural substrates. Undaria pinnatifida is the only Lam-
inarian kelp there; the indigenous phytobenthos is com-
posed of comparatively small seaweeds, like Codium,
Dictyota, Ulva, Anotrichium and Ceramium.

Although sporophytes are present all year round,
they are most abundant and become fertile by the
end of winter. In spring, when they attain their maxi-
mal development, they can exceed a meter in height.
The crowded sporophytes are anchored by their con-
spicuous holdfasts, which overlap and entangle with
each other, covering the original vegetation; their wide
blades form a canopy that produces significant shad-
ing on the bottom. The seascape in those sites has
changed dramatically; a situation that will reoccur
in other places where Undaria populations develop.
Undaria pinnatifida is now regularly found among
seaweeds cast ashore along the beaches of Puerto
Madryn city. Large dislodged thalli are pulled by
the tides disturbing the bottom and benthic commu-
nities along their track. Undaria also constitutes a new
potential food source for local grazers, like the gas-
tropod Tegula patagonica d’Orbigny (1835) and the
sea urchins Arbacia dufresnii Blainville (1825) and
Pseudechinus magellanicus Philippi (1857).

By late 1999, it was found in Caleta Malaspina
(Figure 1), about 500 km from Puerto Madryn. Here
it poses a serious threat, as it could compete with
native seaweeds of economical significance, like
Gracilaria gracilis (Stakhouse) Steentoft, Irvine and
Farnham (1995), Gigartina skottsbergi Setchell and
Gardner (1937), and Macrocystis pyrifera (Linnaeus)
C. Agardh (1820).

Ships leaving Puerto Madryn transport ballast water
in their empty holds. Even though legislation to prevent



134

bioinvasions via ballast water does exist in Argentina,
it is seldom enforced. Seawater temperatures in many
Argentine coastal locations match those reported as
optimal for its development well, thus creating a sce-
nario that may facilitate its spread. Recreational and
artisanal fishing boats often commute between the
Nuevo and San José Gulfs. The latter being a marine
park of great ecological and economic significance,
strict controls and education of the public are urgently
needed to prevent an impending ecological disaster.
Once established, eradication of populations seems
impracticable: if just the large sporophytes (the most
visible stage) were targeted, only half of the problem
would be attacked. Undaria constitutes a potential eco-
nomic resource as human food, and so commercial
harvesting could have some merit as part of a control
strategy.

To our best knowledge, this is the only docu-
mented case of exotic macrolgae introduction in the
southwestern Atlantic.

Spartina anglica Hubbard (1968)
The origins of this species are convoluted. After
the accidental introduction of S. alterniflora Loisel.
(1807), to England (with ship ballast), the latter nat-
urally crossed with the native S. maritima (Curtis)
Fernald (1916) (the only species of the genus that
is not found in the Americas), generating the vigor-
ous hybrid S. × towsendii H. and J. Groves (1881).
Spartina anglica (a name that seems to be strictly
invalid but widely accepted to identify this organ-
ism; Gray et al. 1990) is a fertile organism originat-
ing from chromosomal doubling of the sterile hybrid
S. × towsendii (Gray et al. 1990; Briggs and Walters
1997). It has vigorous vegetative growth contrasting
with poor seed production. Like many other C4 grasses,
S. anglica does not commence canopy development
until air temperature exceeds 9 ◦C. As suggested for
northwestern Europe (Marks and Mullins 1990), this
fact could be the reason why its growing season is short-
ened in comparison with several native C3 perennial
grass species.

Spartina anglica, showing high inter- and intra-
population phenotypic variation, can be a pioneer
species in exposed tidal flats, as well as an established
one in the middle and high marsh. Highly competitive
and tolerant to submergence, it can invade mudflats
replacing native seagrasses and mangrove commu-
nities, eventually altering the entire native faunistic
and floristic composition of a marsh (Chung 1990;

Goss-Custard and Moser 1993). In England and
The Netherlands, for example, it can give origin to
a dense monospecific sward by rapid lateral tus-
sock growth, in combination with high shoot den-
sity and slow rate of establishment of the other
species (Scholten and Rozema 1990). Nowadays,
S. alterniflora is virtually extinct in England, while
S. × towsendii is largely confined to the upper marsh
zone because of competition with S. anglica (Gray
et al. 1990; Adam 1993). However, it appears that its
competitive ability is less effective on cobble beaches
(Hacker et al. 2001) and sandy substrates than on finely
textured ones, depending on physical variables (e.g.
salinity, temperature; Davy and Costa 1992). In fact,
the chances for eradication of this species seem to
be modulated by the interplay between habitat phys-
ical conditions and species interactions (Hacker et al.
2001).

Spartina anglica was not included in major lists
of South American Spartina species, starting with
Brongniart (1829). It was first reported for Tierra del
Fuego (Argentina, Figure 1) in 1959 as S. × towsendii
(Parodi 1959, cited by Nicora 1978), but the date of
its introduction is unknown (Nicora 1978). For many
years, S. anglica was not included in Spartina species
lists due to its cryptic similitude with S. × towsendii
(e.g. Mobberley 1956; Lambert 1964), this being
the reason for its introduction often going unnoticed.
Based on the descriptions by Parodi (1959, cited by
Nicora 1978) of samples from Tierra del Fuego, Nicora
(1978) revised these records, identifying the species
as S. anglica. No other record has been reported
for Argentina, Uruguay or Brazil, where at least
three other Spartina species (S. alterniflora, S. ciliata
Brongn. (1829), and S. densiflora Brongn. (1829))
and a hybrid (S. longispica Hauman and Parodi et
St. Yves (1932); but see Parodi 1937) are known to
occur (West 1977; Cabrera and Zardini 1978; Costa and
Davy 1992). The most recent catalogue of the Poaceae
of Argentina (Zuloaga et al. 1994) does not include
S. anglica.

Considering its area of origin (i.e. UK), it is pos-
sible that S. anglica were intentionally introduced to
the SW Atlantic in the Malvinas (Falklands) Islands
(Figure 1), later dispersing into Tierra del Fuego (south-
ern Argentina). It was planted and sporadically cul-
tivated to favor coastline stabilization in Tierra del
Fuego (Nicora 1978). Worldwide, the ecological con-
sequences of its spread have been significant (e.g. Gray
et al. 1990, Hacker et al. 2001), and control as well as



135

eradication, rather than further planting, have been the
concern of managing authorities in recent years (Adam
1993, Hacker et al. 2001). Despite the dramatic eco-
logical impact that this species could have in the short
term within native saltmarshes, little to no attention has
been directed to confirm its present distribution in the
SW Atlantic.

Overview
Earlier we discussed the six exotic species that are most
significant in terms of their present or future ecolog-
ical impact in the southwestern Atlantic (Figure 2).
Given the scarcity of local studies pertaining to their
ecological effects, it is difficult to predict their future
impacts. Yet, Crassostrea gigas, Balanus glandula,
Undaria pinnatifida and Limnoperna fortunei are likely
to continue spreading along the coast, modifying the
local benthic communities at an even larger scale. The
knowledge of the ecological effects of Spartina anglica
is poor and no field surveys were done in order to
study its biology. Ficopomatus enigmaticus is the best-
studied case. Even though this species is not currently
spreading its range along the coast, their reefs chron-
ically alter the sedimentary dynamics and ecological
interactions in a unique environment, designated by
UNESCO as a MAB site. Could any of these inva-
sions have been predicted? Ecologists that described
patterns of ecological zonation in the rocky intertidal
of the region during the 1960s noticed the absence of a
barnacle belt (Olivier et al. 1966a, b), a common feature
along other temperate coasts of the World. They could
have hypothesized about the likelihood of a barnacle
invasion. In retrospect, the expansion of Crassostrea
in Bahia San Blas, once introduced, was also a rea-
sonable prediction, based on experience from other
regions. In these and other cases, some knowledge
of the pre-invasion conditions is required to gener-
ate workable hypotheses. Our review points in that
direction.

Summary and conclusions

Our survey of recorded invasions of the southwestern
Atlantic by exotic species, the first of its nature for this
region, had results unexpected to us at the onset of the
project. Most coastal ecosystems between the La Plata
River estuary and Golfo Nuevo (Figure 2) have already
been modified, or are expected to be so in the short term.
A barnacle (Balanus glandula) belt has developed on

all rocky shores where none was present 30 years
ago, a macro-fouler (Limnoperna fortunei) and a reef-
builder (Ficopomatus enigmaticus) have strongly mod-
ified estuarine ecosystems, Pacific oyster (Crassostrea
gigas) reefs are expanding in shallow bays at a fast
rate, and kelp (Undaria pinnatifida) is rapidly modify-
ing nearshore benthic communities along the coasts
of central Patagonia. At this point, it is uncertain
how many of the cordgrasses (Spartina spp.) found
in coastal salt marshes correspond to exotic forms.
Only exposed sandy beaches appear to be free from
the pervasive ecological impact of invasion by exotic
species.

Besides, a substantial list of exotics was compiled
(Table 1) and there are many more candidates for
that status (Table 2). If we considered that our survey
included a wide latitudinal range (ca. 20◦), the abun-
dance of exotic species in our coastal systems (n = 31)
is relatively low if compared to other well-studied
areas. As an example, the highly invaded San Francisco
Bay estuary has 150 exotic species in saltwater (exclud-
ing fishes and protozoans; Cohen and Carlton 1998),
while the Chesapeake Bay has 180 exotic species
(excluding fishes, birds and mammals; Ruiz et al. 1999)
and within North America, 255 (Ruiz et al. 2000). This
contrast could reflect the fact that the southwestern
Atlantic has been little studied, or simply that it has
been less exposed to invasions due to the lower intensity
of maritime transportation. Attending to the geographic
distribution of references (Introduction, Figure 1), and
taking frequencies in our sample of 344 references
as an index, the ratio of introduced species to refer-
ences in the sample is 31/1 (31) for the southwest-
ern Atlantic. The respective ratios for the West, East
and Gulf coasts of North America (counts of non-
indigenous species from Ruiz et al. 2000, p. 494) are
187/89 (2.1), 108/59 (1.8) and 7/10 (0.7). The higher
the value of the ratio, the lesser the attention given
to non-indigenous species. While the three figures
for North American coasts are commensurate among
them (ca. 2 on average), the value for the southwest
Atlantic is 15-fold larger. This is strongly indicative
of bias.

Even if the number of documented exotics is com-
paratively small, the biodiversity tapestry of the region
has been strongly altered. In many cases, it may be
very difficult to ascertain the real status of a species.
More consequential, it is becoming increasingly diffi-
cult to establish what the pristine condition of coastal
communities was. The paucity of good descriptive,



136

pre-impact work aggravates this problem; the few exist-
ing antecedents (Olivier et al. 1966a, b; 1972a, b;
Penchaszadeh 1973) highlight the significance of that
type of studies.

The results of the survey reveal some patterns of gen-
eral interest. All of the four invading animal species that
have already had a significant ecological impact tend
to concentrate in crowded patches and have pelagic lar-
vae. This combination may provide conditions favor-
able for the rapid spread of an invading species, even
if initially ‘inoculated’ as a small but dense clutch
of reproductive individuals (this was the case for the
Pacific oyster).

There are numerous ways in which exotic marine
and freshwater species are introduced, generally asso-
ciated with human activity. Ships are the main source
of species introduction (via ballast water or fouling;
Ruiz et al. 2000), but intentional translocations of
species for aquaculture, food and sport activities are
also important. Among the exotic species established in
the southwestern Atlantic, only one (the Pacific oyster)
was intentionally introduced, and two (the Pacific oys-
ter and Spartina anglica) have been artificially propa-
gated after their introduction. Most introductions were
accidental, most likely associated with fouled objects
or ballast water discharges. Although Argentina has
regulations regarding the latter, they are not strictly
enforced. It is still not well understood that once aware-
ness has been raised, what were accidents in the past,
in fact become choices in the future. We hope that our
compilation will assist in the implementation of more
proactive policies. Reactive policies are of little use,
as the invasion by a marine exotic is an asymmetric
process: once established, its extirpation is, as a rule,
impossible. Yet, introduced species may be manage-
able in some cases. The development of markets of
potentially usable species (for example, Undaria or the
Pacific oyster) may be part of control strategies.

Prevention and control are particularly important
in the case of ecologically sensitive areas. The best
regional example is San José Gulf, north of Valdés
Peninsula, a major calving ground for southern right
whales and the first marine protected area of the
Argentine coast, recently classified by UNESCO as
part of the World’s Heritage. Preserving it in its pris-
tine condition is a well-established societal goal. Yet,
coastal rocky shores have already been invaded by
Balanus glandula, and the arrival of Undaria is most
likely just a matter of time. Opposite to the better under-
stood problem of chemical contamination, ‘species

contamination’ does not gradually vanish following a
contamination event, rather, it tends to increase and
propagate as time passes (Westbrooks 2000).

As a closing recommendation, it is important that
scientists and scientific agencies in the region under-
stand the urgency of research on systematics and
biogeography. The biodiversity of the southwestern
Atlantic (particularly its warm-temperate sector) is
among the least known in the world. Given that cir-
cumstance, the detection, prevention and control of
biological invasions by exotic species may become
virtually impossible: no one will be able to even read
the winning combinations in the ‘biological roulette’
(Carlton and Geller 1993). If there is a general lesson
to be learned from our scrutiny of introduced species in
the southwestern Atlantic, it is that many areas of the
World currently perceived as relatively pristine may be
already altered by biological invasions.

Acknowledgements

The authors thank the following institutions and
programs for support during the development of
this project: Pew Marine Conservation Collaborative
Project (Lobo Orensanz); CIC (Buenos Aires,
Argentina), and Fundacion Antorchas scholarship
program (Evan Schwindt); Fundación Antorchas,
CONICET (Argentina) and the Andrew Mellon Foun-
dation (Alejandro Bortolus); CONICET (Juan López
Gappa); Dirección Nacional de Recursos Acuáticos (ex
INAPE), Uruguay (Fabrizio Scarabino). We thank the
organizers of the 4th Jornadas Argentinas de Ciencias
del Mar (Puerto Madryn, 11–15 September 2000) for
providing the context that made possible the incep-
tion of this collaborative project. Comments made by
D. Vázquez, J. T. Carlton and three anonymous review-
ers greatly improved the manuscript. Finally, we thank
D. Vázquez, R. Aragón and J. T. Carlton for inviting
us to participate in this special issue of the journal.

References

Acuña FH (1997) Ecologı́a trófica de actiniarios (Cnidaria,
Anthozoa) intermareales: selección de la talla de las presas. Physis
(Argentina) (A) 53(124–125): 1–5

Acuña FH and Zamponi MO (1996) Trophic ecology of the inter-
tidal sea anemones Phymactis clematis Dana, 1849, Aulactinia
marplatensis (Zamponi, 1997) and A. reynaudi (Milne-Edwards,
1857) (Actiniaria: Actiniidae): relationships between sea



137

anemones and their prey. Ciencias Marinas (Ensenada, México)
22: 397–413

Acuña FH and Zamponi MO (1997) El uso de los cnidocistos para
la identificación de razas ecológicas en poblaciones de anémonas
de mar (Anthozoa, Actiniidae). Iheringia (Porto Alegre, Brazil)
(Zoology) 82: 9–18

Adam P (1993) Saltmarsh Ecology. Cambridge Studies in Ecology.
Cambridge University Press, London, 461 pp

Akiyama K and Kurogi M (1982) Cultivation of Undaria pinnatifida
(Harvey) Suringar, the decrease in crops from natural plants fol-
lowing crop increase from cultivation. Tohoku Regional Fisheries
Research Laboratory Bulletin 44: 91–100

Allen FE (1953) Distribution of marine invertebrates by ships.
Australian Journal of Marine and Freshwater Research 4:
307–316

Alonso G (1986) Nuevos registros de anfı́podos marinos
(Amphipoda, Gammaridea) para la Argentina. Physis (Argentina)
(A) 44(107): 67–69

Alonso G (1997) Records of intertidal amphipods from the southwest
Atlantic, with the description of a new species of Elasmopus.
Journal of Crustacean Biology 17: 745–757

Alonso G, Tablado A, López Gappa J and Magaldi N (1996) Seasonal
changes in an intertidal population of the amphipod Ampithoe
valida Smith, 1873. Oebalia 21: 77–91

Amaro J (1965) La familia Mytilidae en el Uruguay (Segunda parte).
Revista del Instituto de Investigaciones Pesqueras (Uruguay) 1:
323–339

Amor A (1964) Ascidias nuevas para la fauna argentina. Physis
(Argentina) 24(68): 351

Amor A and Pallares RE (1965) Entoprocta y Ectoprocta de la
Ria de Deseado (Santa Cruz, Argentina) y de otras localidades
patagónicas. Physis (Argentina) 25(70): 291–317

Angelis D’Ossat GD (1908) Altri Zoantari del terziario della Patag-
onia. Anales del Museo Nacional de Buenos Aires (Argentina)
(3)9: 93–102

Barattini LP and Ureta EH (1960) La fauna de las costas del este
(invertebrados). Publicaciones de Divulgación Cientı́fica, Museo
‘Dámaso Antonio Larrañaga’, Montevideo (Uruguay), 108 pp

Bastida R (1971) Las incrustaciones biológicas en el puerto de
Mar del Plata. Perı́odo 1966/67. Revista del Museo Argentino
de Ciencias Naturales ‘Bernardino Rivadavia’ 3: 203–285

Bastida R, Trivi de Mandri M, Lichtschein de Bastida V and
Stupak M (1980) Ecological aspects of marine fouling at the
Port of Mar del Plata (Argentina). V Congreso Internacional de
Corrosión Marina e Incrustaciones, Madrid, pp 229–320

Bernard FR (1983) Catalogue of the living Bivalvia of the east-
ern Pacific Ocean: Bering Sea to Cape Horn. Canadian Special
Publication of Fisheries and Aquatic Sciences 61, 102 pp

Berroa-Belén C (1989) Notas sobre esponjas uruguayas. 3. Boletı́n
de la Sociedad Zoológica del Uruguay (Segunda Epoca) 5: 33–34

Bisbal GA (1995) The Southeast South American shelf large marine
ecosystem. Marine Policy 19: 21–38

Blanco O (1964) Algunos campanularidos argentinos. Revista del
Museo de La Plata (Argentina) (NS) 8(61): 149–171, 2 pls

Blanco O (1966) Ramificación en Plumularia setacea (Ellis)
(Hydrozoa-Plumulariidae). Neotropica (Argentina) 12(39):
100–102

Blanco O (1967) Nueva distribución para Obelia gracilis Calkins
(un caso de epibiosis). Revista del Museo de La Plata (Argentina)
(NS) 10: 129–136

Blanco O (1968) Nueva contribución al conocimiento de la fauna
marina hydroide. Revista del Museo de La Plata (Argentina) (NS)
10: 195–224

Blanco O (1974) Adición a los hidrozoos argentinos. Neotropica
(Argentina) 20(61): 43–47

Blanco O (1976) Hidrozoos de la Expedición Walther Herwig.
Revista del Museo de La Plata (Argentina) (Zoologia) 12(113):
25–66, 8 pls

Blanco OM and Morris M (1977) Nueva cita para Obelia genic-
ulata (L.) (Hydroida-Campanulariidae). Neotropica (Argentina)
23(69): 91–93

Blake JA (1983) Polychaetes of the family Spionidae from South
America, Antarctica, and adjacent seas and islands. Biol-
ogy of the Antarctic Seas 14. Antarctic Research Series 39:
205–288

Blake JA and Maciolek NJ (1987) A redescription of Polydora cor-
nuta Bosc (Polychaeta: Spionidae) and designation of a neotype.
Bulletin of the Biological Society of Washington 7: 11–15

Borg F (1944) The stenolematous Bryozoa. Further Zoological
Results of the Swedish antarctic Expedition (1901–1903) 3(5),
276 pp

Boschi EE, Iorio MI and Fischbach K (1992) Catálogo ilustrado de
los crustaceos estomatópodos y decápodos marinos de Argentina.
Frente Marı́timo (Argentina/Uruguay) 10: 7–94

Boudouresque CF, Gerbal M and Knoepffler-Peguy M (1985)
L’algue japponnaise Undaria pinnatifida (Phaeophyceae,
Laminariales) en Mediterranée. Phycologia 24: 364–366

Bousfield E (1973) Shallow-Water Gammaridean Amphipoda of
New England. Cornell University Press, 212 pp

Brandt A (1991) Zur Besiedlungsgeschichte des antarktischen
Schelfes am Beispiel der Isopoda (Crustacea, Malacostraca).
Berichte zur Polarforschung 98, 240 pp

Bremec CS (1989) Macrobentos del área de Bahı́a Blanca
(Argentina). Inventario faunı́stico. Investigaciones Marinas
(La Paz, México) 4: 175–190

Briggs D and Walters SM (1997) Plant variation and evolution.
Cambridge University Press, New York, 512 pp

Brongniart MA (1829) Phanérogamie. In: Bertrand A (ed) Voyage
Autour du Monde sur la Corvette La Coquille, pendant les anées
1822–1825 par M.L. Duperrey. Paris

Burton M (1934) Sponges. Further Zoological Results of the Swedish
Antarctic Expedition (1901–03) 3(2): 1–58

Burton M (1940) Las esponjas marinas del Museo Argentino de
Ciencias Naturales ‘Bernardino Rivadavia’. Anales del Museo
Argentino de Ciencias Naturales 40: 95–121

Cabrera AL and Zardini EM (1978) Manual de la Flora de los
Alrededores de Buenos Aires. 2da ed. Editorial Buenos Aires
(Argentina), 755 pp

Calcagno JA, López Gappa JJ and Tablado A (1997) Growth and pro-
duction of the barnacle Balanus amphitrite Darwin in an intertidal
area affected by sewage pollution. Journal of Crustacean Biology
17: 417–423

Calcagno JA, López Gappa JJ and Tablado A (1998) Population
dynamics of the barnacle Balanus amphitrite in an intertidal area
affected by sewage pollution. Journal of Crustacean Biology 18:
128–137

Campbell SJ and Burridge TR (1998) Occurrence of Undaria
pinnatifida (Phaeophyta: Laminariales) in Port Phillip Bay,
Victoria, Australia. Marine and Freshwater Research 49:
379–381



138

Capitoli RR, Bemvenuti CE and Gianuca NM (1978) Estudos
de ecologı́a bentônica na região estuarial da Lagoa dos Patos.
I: Comunidades bentônicas. Atlântica (Rio Grande, Brazil)
3: 5–22

Carcelles AR (1944) Catálogo de los moluscos marinos de Puerto
Quequén (República Argentina). Revista del Museo de La Plata
(Argentina) (NS, Zoologia) 3: 233–309, 15 pls

Carcelles AR and Williamson S (1951) Catálogo de los
moluscos marinos de la Provincia Magallánica. Revista del
Museo Argentino de Ciencias Naturales (Zoologia) 2(5):
225–383

Carlton JT (1985) Transoceanic and interoceanic dispersal of coastal
marine organisms: the biology of ballast water. Oceanography and
Marine Biology Annual Review 23: 313–374

Carlton JT (1987) Patterns of transoceanic marine biological inva-
sions in the Pacific Ocean. Bulletin of Marine Science 41:
452–465

Carlton JT (1996) Biological invasions and cryptogenic species.
Ecology 77: 1653–1655

Carlton JT and Geller JB (1993) Ecological roulette: the global
transport of nonindigenous marine organisms. Science 261:
78–82

Casas GN and Piriz ML (1996) Surveys of Undaria pinnati-
fida (Laminariales, Phaeophyta) in Golfo Nuevo, Argentina.
Hydrobiologia 326/327: 213–215

Castellanos ZA de and Fernández D (1965) Sobre la presencia de
Donax hanleyanus en la costa argentina. Neotrópica (Argentina)
11(35): 58

Chapman JW and Carlton JT (1991) A test of criteria for introduced
species: the global invasion by the isopod Synidotea laevidorsalis
(Miers, 1881). Journal of Crustacean Biology 11: 386–400

Chung CH (1990) Twenty-five years of introduced Spartina anglica
in China. In: Gray AJ and Benham PEM (eds) Spartina anglica:
A Research Review. Institute of Terrestrial Ecology, London,
79 pp

Coan EP, Valentich S and Bernard FR (2000) Bivalve Seashells
of Western North America. Santa Barbara Museum of Natural
History, Santa Barbara, 764 pp

Codina R, Delucia A, Damborenea C and Darrigran G (1999)
Pautas cientı́ficas para el control de Limnoperna fortunei
(Bivalvia: Mytilidae) en la central hidroeléctrica Yacyretá, Rı́o
Paraná (Argentina- Paraguay). IV Congreso Latinoamericano de
Malacologia (Coquimbo, Chile), p 8 (abstract only)

Cohen AN and Carlton JT (1998) Accelerating invasion rate in a
highly invaded estuary. Science 279: 555–557

Costa CSB and Davy AJ (1992) Coastal saltmarsh communities of
Latin America In: Seeliger U (ed) Coastal Plant Communities of
Latin America, pp 179–212. Academic Press, New York

Cornelius PFS (1975) The hydroid species of Obelia (Coelenterata,
Hydrozoa: Campanulariidae), with notes on the medusa stage.
Bulletin of the British Museum of Natural History (Zoology)
28(6): 251–293

Cornelius PFS (1982) Hydroids and medusae of the family Campan-
ulariidae recorded from the eastern North Atlantic, with a world
synopsis of the genera. Bulletin of the British Museum of Natural
History (Zoology) 42: 37–148

Cuartas EI (1991) Demospongiae (Porifera) de Mar del Plata
(Argentina), con la descripcion de Cliona lisa sp.n. y Plicatel-
lopsis reptans sp.n. Neritica (Curitiba, Brazil) 6: 43–63

Cuartas EI and Excoffon AC (1993) La fauna acompañante
de Hymeniacidon sanguinea (Grant, 1827) (Porifera:
Demospongiae). Neotropica (Argentina) 39(101–102): 3–10

Curiel, D, Rismondo A, Marzocchi M and Solazzi A (1994) Undaria
pinnatifida (Harvey) Suringar (Laminariales, Phaeophyta) nella
Laguna di Venezia. Lavori della Societá Veneta delle Science
Naturale 19: 121–126

Darrigran G (1995) Limnoperna fortunei, ¿un problema para los
sistemas naturales de agua dulce del Mercosur? Museo (La Plata,
Argentina) 5: 85–87

Darrigran G (1997a) Introduction of harmful aquatic organ-
isms bivalves, River Plate. MEPC.40/10/1: 1–17. International
Maritime Organization

Darrigran G (1997b) Invasores en la Cuenca del Plata. Ciencia Hoy
(Argentina) 7(38): 17–22

Darrigran G (2000) Invasive Freshwater Bivalves of the Neotropical
Region. Dreissena! 11: 7–13

Darrigran G and Ezcurra de Drago I (2000) Invasion of freshwater
mussel, Limnoperna fortunei (Dunker, 1857) (Mytilidae) in the
Americas. The Nautilus 114: 69–73

Darrigran G and Pastorino G (1995a) The recent introduction of
the Asiatic bivalve Limnoperna fortunei (Mytilidae) into South
America. The Veliger 38: 183–187

Darrigran G and Pastorino G (1995b) Bivalvos invasores en el Rı́o de
la Plata, Argentina. Comunicaciones de la Sociedad Malacológica
del Uruguay 7(64–65): 309–313

Darrigran G, Martin SM, Gullo B and Armendariz L (1998)
Macroinvertebrate associated to Limnoperna fortunei (Dunker,
1857) (Bivalvia, Mytilidae) in the Rı́o de La Plata, Argentina.
Hydrobiologia 367: 223–230

Darrigran G, Penchaszadeh P and Damborenea C (1999) The repro-
ductive cycle of Limnoperna fortunei (Dunker, 1857) (Mytilidae)
from a Neotropical temperate locality. Journal of Shellfish
Research 18: 361–365

Darwin C (1854) A Monograph of the Subclass Cirripedia with
figures of all the species. The Balanidae, the Verrucidae, etc. Ray
Society, London, 684 pp

Davy AJ and Costa CSB (1992) Development and organization
of saltmarsh communities. In: Seeliger U (ed) Coastal Plant
Communities of Latin America, pp 157–178. Academic Press,
New York

Dell RK (1964) Antarctic and Subantarctic Mollusca: Amphineura,
Scaphopoda and Bivalvia. Discovery Reports 33: 93–250,
pls 2–7

Dei Cas EV and Mañé–Garzón F (1973) Heteronereidización en
Nereis (Neanthes) succinea Leuckart en el Rı́o de La Plata. Traba-
jos del V Congreso Latinoamericano de Zoologı́a (Montevideo,
Uruguay) 1: 72–84

D’Orbigny AD (1847) Zoophytes. In: Voyage dans l’Amerique
Me’ridionale 5(4): 7–28

Dumoulin E and De Blauwe H (1999) Het bruinwier Undaria pinnat-
ifida (Harvey) Suringar (Phaeophyta: Laminariales) aangetroffen
in de jachthaven van Zeebrugge met gegevens over het voorkomen
in Europa en de wijze van verspreiding. De Strandvlo 19(4):
182–188

Elı́as R and Vallarino EA (2001) The introduced barnacle Balanus
glandula (Darwin) in the Mar del Plata port as a structuring
species in the intertidal community. Investigaciones Marinas
(Valparaiso, Chile) 29: 37–46



139

Escofet A (1973) Los géneros de anfı́podos mas comunes en el
área de Mar del Plata-Clave para su reconocimiento. Instituto
de Biologı́a Marina (Mar del Plata), Contribución 239, 22 pp

Esteves JL, Ciocco NF, Colombo JC, Freije H, Harris G, Iribarne O,
Isla I, Nabel P, Pascual MS, Penchaszadeh PE, Rivas AL and
Santinelli N (2000) The Argentine Sea: the Southeast South
American shelf marine ecosystem. In: Sheppard CRC (ed) Seas
at the Millenium: An Environmental Evaluation, pp 749–771.
Pergamon, New York

Excoffon AC and Zamponi MO (1995) Reproducción de Oculactis
muscosa Dana, 1849 (CNIDARIA, ACTINIARIA) en el inter-
mareal de Mar del Plata, Argentina. COLACMAR VI: 76 (abstract
only)

Farinati EA (1985) Paleontologı́a de los sedimentos marinos
holocenos de los alrededores de Bahı́a Blanca, Provin-
cia de Buenos Aires. Ameghiniana (Argentina) 21(2/4):
211–222

Fasano JL, Hernández MA, Isla FI and Schnack EJ (1982) Aspectos
evolutivos y ambientales de la laguna Mar Chiquita (Provincia
de Buenos Aires, Argentina). Oceanologica Acta (special issue):
285–292

FAO (1999) Aquaculture Production Statistics 1988–1997. FAO
Fisheries Circular No 815, Revision 11. Rome, Italy, 203 pp

Figueiras A and Sicardi OE (1968) Catálogo de los moluscos mari-
nos del Uruguay (Parte II). Comunicaciones de la Sociedad
Malacológica del Uruguay 2(15): 255–273, 2 pls

Figueiras A and Sicardi OE (1970a) Catálogo de los moluscos
marinos del Uruguay. Parte IV. Comunicaciones de la Sociedad
Malacológica del Uruguay 2(18): 407–421, 2 pls

Figueiras A and Sicardi OE (1970b) Catálogo de los moluscos mari-
nos del Uruguay. Adiciones y correcciones a la Clase Pelecypoda.
Comunicaciones de la Sociedad Malacológica del Uruguay 3(19):
15–22, 1 pl

Figueiras A and Sicardi OE (1974) Catálogo de los moluscos mari-
nos del Uruguay. Parte IX. Comunicaciones de la Sociedad
Malacológica del Uruguay 3(26): 323–352, pls 18–21

Figueiras A and Sicardi OE (1980a) Catálogo de los moluscos mari-
nos del Uruguay. Parte X. Revisión actualizada de los molus-
cos marinos del Uruguay con descripción de las especies agre-
gadas. Sección I – Polyplacophora – Scaphopoda – Bivalvia.
Comunicaciones de la Sociedad Malacológica del Uruguay 5(37):
107–157, 2 pls

Figueiras A and Sicardi OE (1980b) Catálogo de los moluscos
marinos del Uruguay. Parte X. Revisión actualizada de los molus-
cos marinos del Uruguay con descripción de las especies agre-
gadas. Sección II – Gastropoda y Cephalopoda. Comunicaciones
de la Sociedad Malacológica del Uruguay 5(38): 179–272,
pls 3–6

Fletcher RL and Manfredi C (1995) The occurrence of Undaria
pinnatifida (Phaeophyceae, Laminariales) on the South Coast of
England. Botanica marina 38: 355–358

Fornós JJ, Forteza V and Marı́nez Taberner A (1997) Modern
polychaete reefs in Western Mediterranean lagoons: Ficopoma-
tus enigmaticus (Fauvel) in the Albufera of Menorca, Balearic
Islands. Palaeogeography, Palaeoclimatology and Palaeoecology
128: 175–186

Foster MS, de Vogelaere AP, Olivier JS, Pearse JS and Harrold C
(1991) Open coast intertidal and shallow subtidal ecosystems
of the northeast Pacific. In: Mathieson AC and Nienhuis PH

(eds) Intertidal and Littoral Ecosystems, pp 253–272. Elsevier,
New York

Genzano GN (1988) Hallazgo de Gonothyrea loveni (Allman, 1859)
(Hydrozoa: Campanulariidae) en el estuario del Rio de La Plata.
Spheniscus (Argentina) 7: 11–12

Genzano GN (1990) Hidropólipos (Cnidaria) de Mar del Plata,
Argentina. Neritica (Curitiba, Brazil) 5: 35–54

Genzano GN (1995) New records of hydropolyps (Cnidaria,
Hydrozoa) from south–western Atlantic Ocean. Miscelanea
Zoologica 18: 1–8

Genzano GN (1998) Hydroid epizoites on hydroids Tubularia crocea
and Sertularella mediterranea from the intertidal of Mar del Plata
(Argentina). Russian Journal of Marine Biology 24: 123–126
(English translation)

Genzano GN and Rodriguez GM (1998) Association between
hydroid species and their substrates from the intertidal zone of
Mar del Plata (Argentine). Miscelanea Zoologica 21(1)

Genzano G and Zamponi M (1992) Los hidrozoos bentónicos de la
costa de Mar del Plata. Universidad Nacional de Mar del Plata
(Argentina), 89 pp

Genzano G, Cuartas E and Excoffon A (1991) Porifera y Cnidaria
de la Campaña Oca Balda 05/88. Thalassas 9: 63–78

Giambiagi D (1922) Cuatro nuevos isopodos de la Argentina. Physis
(Argentina) 5(20): 230–244

Giambiagi D (1923) Una nueva especie de Tanais. Physis (Argentina)
6: 248–251

Giambiagi D (1931) Oniscoideos del rı́o de La Plata (primera parte).
Anales del Museo Nacional de Buenos Aires (Argentina) 36:
417–429, 9 pls

Giambiagi D (1935) Un isópodo nuevo, Philoscia bonariensis.
Physis (Argentina) 11(40): 495–495

González LA (1974) Hallazgo de Neomysis americana Smith (1873)
(Crustacea: Mysidacea) en el Rı́o de La Plata. Revista de Biologı́a
del Uruguay 11: 119–130

Gordon DP and Mawatari SF (1992) Atlas of marine–fouling bryozoa
of New Zealand ports and harbours. New Zealand Oceanographic
Institute, Miscellaneous Publication 107, 52 pp

Goss-Custard JD and Moser ME (1993) Changes in the numbers of
dunlin (Calidris alpina) in British estuaries in relation to changes
in the abundance of Spartina. In: Gray AJ and Benham PEM
(eds) Spartina anglica: A Research Review. Institute of Terrestrial
Ecology, London, 79 pp

Gray AJ, Benham PEM and Raybould AF (1990) Spartina anglica–
the evolutionary and ecological background. In: Gray AJ and
Benham PEM (eds) Spartina anglica: A Research Review.
Institute of Terrestrial Ecology, London, 79 pp

Hacker SD, Heimer D, Hellquist CE, Reeder TG, Reeves B,
Riordan TJ and Dethier MN (2001) A marine plant (Spartina
anglica) invades widely varing habitats: potential mechanisms of
invasion and control. Biological Invasions 3: 211–217

Harding JM and Mann R (1999) Observations on the biology of the
veined rapa whelk, Rapana venosa (Valenciennes, 1846) in the
Chesapeake Bay. Journal of Shellfish Research 18: 9–17

Hastings AB