209
ABSTRACT. Magallana gigas
M. gigas
M.
gigas
±±
±M. gigas
M. gigas
M. gigas
Key words:
Distribución, abundancia y estructura de tamaño de la ostra cóncava del Pacíco, Magallana
gigas, en el norte de la Patagonia
RESUMEN. Magallana gigas
M. gigas
M. gigas
Distribution, abundance, and size structure of the Pacic cupped oyster
Magallana gigas in northern Patagonia
2
LeandroA. Hünicken Raúl González
Dennis Landete Maité A. Barrena
Juan F. Saad Maite A. Narvarte
Marine and
Fishery Sciences
MAFIS
Marine and Fishery Sciences 38 (2): 209-225 (2025)
Magallana =Crassostrea
gigas
M.
gigas
'''
±±
±M. gigas
M. gigas
M. gigas
Palabras clave:
Hünicken et al.: Pacific cupped oyster in north Patagonia 211
A monitoring eort that began in 2008 tracked
M. gigas distribution along the northern coast of
the Province of Río Negro. Findings indicated
higher densities near El Cóndor’s central beach
and a 30-km western expansion, reaching near
the eastern limit of San Matías Gulf (Roche et al.
2010) (Figure 1). However, the program ceased
in 2011, leaving the current species distribution
unknown in an area that encompasses four protect-
ed natural zones and a crucial provincial shing
reserve (Provincial laws 1960, 2519, 3222, 2670,
2669; http://www.legisrn.gov.ar). Since impacts of
invasive species depend on distribution, abundance,
and other ecological factors (Markert et al. 2010),
assessing these parameters for M. gigas an initial
step to evaluate its potential eects in the area.
Environmental conditions at the invasion front
that aect the survival and individual growth of
colonizing individuals can profoundly inuence
the establishment and subsequent dispersal of the
invasive species (Burton et al. 2010). The original
monitoring of the cupped oyster in the Province
of Río Negro (Roche et al. 2010) and a prelimi-
nary survey carried out in April 2019 in El Cón-
dor revealed the persistence of the species in the
area, although in relatively very low abundance
(approximately 0.1 ind. m-2) in comparison with
those reached in other natural environments in the
world and Argentina (Bahía Anegada: 90 ind. m-2,
Escapa et al. 2004; Las Toninas: 131 ind. m-2, Gi-
berto et al. 2012; Sylt, Wadden Sea: 125.8 ind. m-2,
Diederich et al. 2005). In other locations where M.
gigas was introduced, lag phases were observed.
For example, in Sylt, Wadden Sea, the rst estab-
lished populations emerged 17 years post-commer-
cial introduction (Wehrmann et al. 2000), while in
Figure 1. Distribution of Magallana gigas on the northern coast of the Province of Río Negro, Argentina. Years in brackets indicate
rst report in the corresponding site.
Marine and Fishery Sciences 38 (2): 209-225 (2025)
M. gigas
M. gigas
Distribution
'
''
'
M. gigas
Ostrea spreta
O. puelchana
M. gigas
M. gigas
Magallana gigas
Ostrea
M. gigas
M. gigas
Abundance
M. gigas
Hünicken et al.: Pacific cupped oyster in north Patagonia
2
2
per
per
=
2
Size structure
Environmental variables
Substrate availability in study sites
Sporobolus Spartina alterni-
oraS. densiora
Marine and Fishery Sciences 38 (2): 209-225 (2025)
Sal-
icorniaSporobolu
Physicochemical and biological environment
in situ
~
a
µ
a
a
µ
α=
Distribution
Magallana gigas
Abundance
Hünicken et al.: Pacific cupped oyster in north Patagonia
Size structure
±
>
Environmental variables
Magallana gigas
±
±
±
±
±
Magallana gigas
Marine and Fishery Sciences 38 (2): 209-225 (2025)
±±
±
a
=
p<
a
M. gigas
±
±
aµ
± ± ± ± ± ± ±
± ± ± ± ± ± ±
± ± ± ± ± ± ±
Hünicken et al.: Pacific cupped oyster in north Patagonia
± 0.6
Pc1 (38 9% explained variance).
Pc2 (30 3% explained variance).
42
0
-2
3
2
1
0
-1 Sites
El Cóndor
Los Pocitos
Piedras Verdes
Temperature
Salinity
TSS
pH
Marine and Fishery Sciences 38 (2): 209-225 (2025)
M. gigas
M. gi-
gas
a
a
M.
gigas
Hünicken et al.: Pacific cupped oyster in north Patagonia
M. gigas
O. puelchana
M. gigas
M. giga
M. gigas
Marine and Fishery Sciences 38 (2): 209-225 (2025)
220
Author contributions
Cras-
sostrea gigas
Crassostrea gigas
Crassostrea gigas
Crassostrea gigas
Crassostrea gi-
Hünicken et al.: Pacific cupped oyster in north Patagonia
gas
Crassostrea gigas
Crassostrea gigas
Crassos-
trea gigas
Crassos-
trea gigas
Crassostrea
gigas
Crassostrea gigas
Crassostrea gigas
Crassostrea gigas
Crassostrea
gigas
Crassostrea
gigas
Crassostrea gi-
gas
Marine and Fishery Sciences 38 (2): 209-225 (2025)
222
Crassotrea gigas
Crassostrea
gigas
Crassostrea gigas
Crassostrea gigas
Cras-
sostrea gigas
Bonasa umbellus
Crassostrea
Mytilus
Crassostrea gigas
Crassostrea gigas
Hünicken et al.: Pacific cupped oyster in north Patagonia
Cras-
sostrea gigasOstrea edulis
Crassostrea gigas
Crassostrea gigas
Crassostrea gigas
Crassostrea gigas
Marine and Fishery Sciences 38 (2): 209-225 (2025)
Magallana gigas
aa
a
µ
± ± ± ± ± ±
± ± ± ± ± ±
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± ± ± ± ± ±
± ± ± ± ± ±
± ± ± ± ± ±
± ± ± ± ± ±
± ± ± ± ± ±
Hünicken et al.: Pacific cupped oyster in north Patagonia
a
µ
± ± ± ± ± ±
± ± ± ± ± ±
± ± ± ± ± ±
± ± ± ± ± ±
± ± ± ± ± ±
± ± ± ± ± ±
± ± ± ± ±
a
Magallana gigas
aa.
a
a
