Solapamiento trofico entre el lobo marino de un pelo Otaria flavescens y la pesqueria de arrastre demersal del golfo San Matias, Patagonia, Argentina

Romero, M. Alejandra; Dans, Silvana Laura; González, Raúl; Svendsen, Guillermo; García, Néstor; Crespo, Enrique

doi:10.3856/vol39-issue2-fulltext-16

Cited by 28 publications

(32 citation statements)

References 24 publications

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Section: Discussionsupporting

confidence: 91%

“…2). This is in line with previous dietary studies that also reported fish to be the dominant prey items consumed by this otariid (Thompson et al 1998, Koen Alonso et al 2000, Suárez et al 2005, Romero et al 2011, Bustos et al 2012.In the present study, Raneya brasiliensis was clearly the dominant prey species throughout the sampling period, since it was the most frequent and abundant fish item and contributed 75% to the IRI (Table 1) On the other hand, some authors have suggested that hake Merluccius hubbsi make an important contribution to the diet of the South American sea lions from Patagonia, after analysis of the stomach contents of individuals found dead on the beach or recovered from incidental catches (Koen Alonso et al , Romero et al 2011). However, in other studies based on scat analysis, including the present one, hake was shown to be absent or poorly represented in the diet of Otaria flavescens (Table 2) (Suárez et al 2005, Bustos et al 2012).…”

supporting

confidence: 91%

“…Therefore, C. guatucupa is the only fish species of commercial interest with a relatively important contribution to the diet of South American sea lions, even though it is not targeted by the commercial fisheries operating in the study area. Previous studies on the diet of Otaria flavescens have shown that they generally consume fish prey of a smaller size than that of fish caught by fisheries (Koen Alonso et al 2000, Szteren et al 2004, Suárez et al 2005, Romero et al 2011). In particular, some authors demonstrated that sea lions feed mainly on juveniles up to 1 yr of age, which are smaller than fish from commercial landings (350 to 400 mm) (Cousseau & Perrota 2004).…”

Section: Discussionmentioning

confidence: 99%

“…South American sea lions seem to be generalist and opportunistic predators, with fish being the main prey group, followed by cephalopods and crustaceans (Thompson et al 1998, Koen Alonso et al 2000, Bustos et al 2012. However, studies on the diet of Otaria flavescens populations distributed along the Argentine coast are scarce, and most of them reported only preliminary results (Koen Alonso et al 2000, Suárez et al 2005, Romero et al 2011, Bustos et al 2012). These studies were based on stable isotope techniques and the analysis of stomach contents and scats.…”

Section: Abstract: Otaria Flavescens · Summer Diet · Scats · Patagonmentioning

confidence: 99%

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Diet of the South American sea lion Otaria flavescens during the summer season at Río Negro, Patagonia, Argentina

Bustos¹,

Daneri²,

Volpedo³

et al. 2014

Aquat. Biol.

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The South American sea lion Otaria flavescens population from northern Patagonia was under intensive commercial harvesting pressure between 1930 and 1950 and is currently increasing at a rate of nearly 6% yr −1. Food availability in the oceans is one of the most important factors influencing the survival and dynamics of marine mammal populations. The objective of the present study was to determine the summer diet of O. flavescens by faecal analysis, in order to assess its trophic behavior, determine whether there are interannual differences in diet composition, and evaluate the potential interaction between fisheries operating in the study area and the species. Present results show that O. flavescens preys mainly on fish species, with Raneya brasiliensis being the most frequent (frequency of occurrence, %FO = 65.7) and abundant (%N = 47.9) fish prey. Cephalopods were the second most important prey item in terms of %FO (42.6%), with the highest index of relative importance corresponding to the octopod Octopus tehuelches. Since these prey taxa are not targeted by the commercial fishing fleet that operates in the study area, the overlap in the use of resources by O. flavescens and fisheries may not be substantial. Given that the biomass of the prey species mentioned above is not directly affected by fishery activities during summer, a greater amount of food may be available for sea lions, with this factor possibly contributing to the population recovery in the area. KEY WORDS: Otaria flavescens · Summer diet · Scats · Patagonia · ArgentinaResale or republication not permitted without written consent of the publisher Aquat Biol 20: 235-243, 2014 Ocean) (King 1983, Bastida et al. 2007). The population inhabiting the Argentine coast dramatically declined between the 1930s and 1950s due to commercial hunting, but since 1990 it has been increasing at a rate of nearly 6% yr −1 , Grandi et al. 2010.The fisheries that operate in the San Matías Gulf, Río Negro province, target demersal and pelagicdemersal species, with the Argentine hake Merluccius hubbsi being the main species caught throughout the year (Irusta et al. 2003). A trend exists towards major diversification in landings and in creased fishing activity (Romero et al. 2011). The fact that the stock of Argentine hake in the region was reported to have collapsed in the 1990s due to over fishing (Aubone 2000), combined with the extreme reduction of the sea lion population, led to a re organization of the ecosystem (Koen Alonso & Yodzis 2005). This is now characterized by larger populations of the Magellanic penguin Spheniscus magellan icus, Argen tine short-fin squid Illex argen ti nus and Argen tine anchovy Engraulis anchoita (Koen Alonso & Yodzis 2005). Furthermore, predation on hake de creased, while predation on alternative prey, such as Squalus acanthias, increased (Koen Alonso et al. 2000).All foraging trips of the South American sea lions from Patagonia are on the continental shelf of up to 400 km in width, with males moving further from the coast...

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Section: Discussionsupporting

confidence: 91%

supporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Abstract: Otaria Flavescens · Summer Diet · Scats · Patagonmentioning

confidence: 99%

See 2 more Smart Citations

Diet of the South American sea lion Otaria flavescens during the summer season at Río Negro, Patagonia, Argentina

Bustos¹,

Daneri²,

Volpedo³

et al. 2014

Aquat. Biol.

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“…seRgeant, 1973) and has also been suggested specifically for O. flavescens (Ximénez, 1976;geoRge-nascimento et al, 1985). To date dietary studies of O. flavescens populations distributed along the Argentine coast are scarce and most of them have reported preliminary conclusions (Koen alonso et al, 2000;suáRez et al, 2005;DRago et al, 2010;RomeRo et al, 2011). Thus, this is the first detailed study that reports the winter and spring diet of O. flavescens on the Patagonian coast.…”

mentioning

confidence: 99%

The diet of the South American sea lion (Otaria flavescens) at Río Negro, Patagonia, Argentina, during the winter-spring period

Bustos

Daneri

Volpedo

et al. 2012

Iheringia, Sér. Zool.

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ABSTRACT. The South American sea lion, Otaria flavescens (Shaw, 1800) population is steadily expanding along the Patagonian coast of Argentina in the last decades. However, little is known about the feeding ecology of the species in the area. The aim of this study was to analyze the food habits of O. flavescens from 91 scats collected at Río Negro province, during the winter and spring of 2005. Fish occurred in 96% of scats containing prey remains, followed by cephalopods (26%). Raneya brasiliensis (Kaup, 1856) was the most frequent and abundant species occurring in 58.6% of samples and constituting almost 50% of fish predated. Second in importance were Porichthys porosissimus (Cuvier, 1829) and Cynoscion guatucupa (Cuvier, 1830) in terms of occurrence (%FO 20.7) and numbers (29.6%) respectively. The squid Loligo gahi (d'Orbigny, 1835) was the most frequent cephalopod prey (42.1%), whereas Octopus tehuelchus (d'Orbigny, 1834) was the most abundant (77%). The higher amount and diversity of prey found in the spring in comparison with the winter season might be related to a higher feeding activity of seals or to a seasonal increase in food availability in the area. KEYWORDS.Trophic ecology, Pinnipedia, fishes, cephalopods.RESUMEN. Dieta del lobo marino de un pelo sudamericano (Otaria flavescens) en Río Negro, Patagonia, Argentina, durante el invierno y primavera. La población del lobo marino de un pelo sudamericano Otaria flavescens (Shaw, 1800) ha experimentado un crecimiento continuo en las ultimas décadas en las costas de la Patagonia Argentina. Sin embargo, poco se conoce sobre la ecología trófica de la especie en el área. El objetivo de este estudio fue analizar los hábitos alimentarios de O. flavescens a partir de 91 fecas colectadas en la provincia de Río Negro, durante el invierno y la primavera del 2005. Los peces estuvieron presentes en el 96% de las fecas que contenían remanentes presas, seguidos por los cefalópodos (26%). Raneya brasiliensis (Kaup, 1856) fue la especie mas frecuente y abundante ocurriendo en el 58.6% de las muestras y constituyendo casi el 50% de los peces predados. Le siguieron en importancia Porichthys porosissimus (Cuvier, 1829) y Cynoscion guatucupa (Cuvier, 1830) en términos de frecuencia de ocurrencia (%FO 20,7) y abundancia numérica (29,6%) respectivamente. El calamar Loligo gahi (d'Orbigny, 1835) fue el cefalópodo presa mas frecuente (42,1%), mientras que Octopus tehuelchus (d'Orbigny, 1834) fue el mas abundante (77%). La mayor cantidad y diversidad de presas observada en primavera en comparación con el periodo invernal podría estar relacionada a una mayor actividad de forrajeo de los lobos o a un incremento en la disponibilidad de presas en el área.

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Responding to Human Influence: Southern Sea Lion Males Adapt to Harbor Habitats

Rodríguez

Giardino

Mandiola

et al. 2021

Ethology and Behavioral Ecology of Otariids and the Odobenid

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Solapamiento trofico entre el lobo marino de un pelo Otaria flavescens y la pesqueria de arrastre demersal del golfo San Matias, Patagonia, Argentina

Cited by 28 publications

References 24 publications

Diet of the South American sea lion Otaria flavescens during the summer season at Río Negro, Patagonia, Argentina

Diet of the South American sea lion Otaria flavescens during the summer season at Río Negro, Patagonia, Argentina

The diet of the South American sea lion (Otaria flavescens) at Río Negro, Patagonia, Argentina, during the winter-spring period

Responding to Human Influence: Southern Sea Lion Males Adapt to Harbor Habitats

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