Overlap between pinniped summer diet and artisanal fishery catches in Uruguay

Szteren, Diana; Naya, Daniel E.; Arim, Matı́as

doi:10.5597/lajam00057

Cited by 36 publications

(44 citation statements)

References 15 publications

(14 reference statements)

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“…In the Malvinas (Falkland) Islands, Thompson et al (1998) found no overlap between fish consumed by South American sea lions and those catches landed by the fisheries. Similarly, in Uruguay little overlap was observed between the diet of pinnipeds and artisanal fishery catches (Szteren et al, 2004). In Patagonia, a detailed study described an intermediate context of conflict between pinnipeds and fisheries (Koen Alonso et al, 2000), indicating some overlap but not enough to conclude that competition existed with the fishery.…”

Section: Discussionmentioning

confidence: 99%

“…In our study, sea lions showed some overlap with coastal fisheries (bottom trawl fishery) during summer. However, the use of different age classes of the same resource, at different times or spatial locations do not imply less intensity of the interaction (Szteren et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

“…The use of scats is a common approach in pinniped dietary studies (Olesiuk et al, 1990, Ochoa and Acuña 1995, Daneri and Carlini 1999, Naya et al 2002Szteren et al, 2004). This technique has the advantage that samples are easy to collect and can be obtained in large numbers, without generating any stress to the individuals under study (Carey, 1992).…”

Section: Discussionmentioning

confidence: 99%

“…An indirect method consists in studying diet composition (from stomach contents and scats) and analyzing the degree of overlap between sea lion prey preferences and commercial species of fish and other marine species. Food habits studies offer valuable information about biological interactions between sea lions and fisheries (Harwood and Croxall, 1988;Daneri and Carlini, 1999;Koen Alonso et al, 2000, Naya et al, 2002Szteren et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Composition and seasonal variation in the diet of the South American sea lion (<i>Otaria flavescens</i>) from Quequén, Argentina

Suarez¹,

Sanfelice²,

Cassini³

et al. 2005

Lat. Am. J. Aquat. Mamm.

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Diet seasonality in South American sea lions, Otaria flavescens, was studied using 252 scats from a male-exclusive haul-out site located in Puerto Quequén (38º37'S, 58º50'W) Argentina during 2001. Prey species were identified from hard remains and their relative importance was assessed considering frequency of occurrence, abundance and biomass. The main prey consumed by sea lions were teleost fish (20 species), followed by cephalopods (four species) and crustaceans. The raneya, Raneya fluminensis, was the most frequent prey year-round, and the most abundant in autumn and winter. The Argentine anchovy, Engraulis anchoita, and the stripped weakfish, Cynoscion guatucupa, were the most abundant prey in spring and summer, respectively. Seasonal differences in the sizes consumed were only found for C. guatucupa. The sea lions from Puerto Quequén showed a diverse diet, mainly feeding on demersal and pelagic prey. Our study fills a geographical gap on the seasonal variation of the diet of South American sea lions. Two main patterns emerged from studies conducted along the geographic range of the species: (1) O. flavescens is a generalist and opportunist feeder, preying on a wide range of species; mainly those of pelagic and demersal habits, (2) South American sea lions change the frequency and/or specific composition of their diet seasonally, possibly as a result of changes in the relative availability of each species in the environment.Resumen: La variación estacional en la dieta del león marino de América del Sur, Otaria flavescens, fue estudiada a partir de 252 heces recolectadas en una colonia no reproductiva de machos localizada en Puerto Quequén (38º37'S, 58º50'O) Argentina durante el año 2001. Las presas fueron identificadas a nivel de especie a partir de restos duros y su importancia relativa fue evaluada a partir del cálculo de la frecuencia de ocurrencia, la abundancia y la biomasa. Las principales presas consumidas por los leones marinos fueron peces (20 especies), cefalópodos (cuatro especies) y crustáceos. La raneya, Raneya fluminensis, fue la presa más frecuente durante todo el año y la más abundante en otoño e invierno. La anchoíta, Engraulis anchoita, y la pescadilla de red, Cynoscion guatucupa, fueron las presas mas abundantes en primavera y verano respectivamente. Diferencias estacionales en las tallas de las presas consumidas se encontraron sólo en C. guatucupa. Los leones marinos de Puerto Quequén muestran una dieta diversa, consumiendo principalmente especies demersales y pelágicas. Nuestro estudio completa un espacio geográfico con datos sobre la dieta y contribuye al estudio de la variación estacional de la misma en los leones marinos de América del Sur. Así, se completan los estudios a lo largo de casi todo el rango de distribución geográfica. Dos conclusiones principales surgen a partir del presente estudio: (1) O. flavescens es un predador generalista y oportunista que consume un amplio rango de especies, principalmente aquellas de hábitos pelágico y demersal, (2) Los leones marinos d...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Composition and seasonal variation in the diet of the South American sea lion (<i>Otaria flavescens</i>) from Quequén, Argentina

Suarez¹,

Sanfelice²,

Cassini³

et al. 2005

Lat. Am. J. Aquat. Mamm.

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“…The most common sizes of fish landings are between 35 and 45 cm in total length (cousseu & peRRotta, 2004). Nevertheless it is remarkable that the use of different age classes of the same resource, at different times or spatial locations do not imply less intensity of the interaction (szteRen et al, 2004). Therefore there might be an overlap between O. flavescens and fisheries in the use of C. guatucupa as a prey resource, though not in size since this species would prey on juveniles of the southern stocks of C. guatucupa which inhabit the coastal zone (JauReguizaR et al, 2006;militelli & machi, 2006;volpeDo et al, 2007).…”

Section: Previous Dietary Reports Of O Flavescensmentioning

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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Intensive fishing has not forced dietary change in the South American fur seal Arctophoca(=Arctocephalus)australis off Río de la Plata and adjoining areas

Vales

Saporiti

Cardona

et al. 2013

Aquatic Conservation

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ABSTRACT1. South American fur seals (Arctophoca australis) inhabiting the Río de la Plata plume and adjoining areas are known to forage upon a wide range of prey (i.e. pelagic, demersal and benthic species).2. Since the 1960s, trawlers have operated in the area, targeting primarily demersal and benthic species. Carbon and nitrogen stable isotope ratios from 54 adult male fur seals dead stranded along the coast of southern Brazil from 1994 to 2011 were analysed to investigate whether the intensification of fishing in Río de la Plata and adjoining areas since the mid-1990s has reduced the availability of benthic and demersal prey to the growing population of South American fur seals.3. No significant correlation between δ 13 C or δ 15 N values and stranding year was found, thus revealing that fur seals maintained a steady diet over 17 years. 4. Reconstruction of the isotopic landscape of the study area using potential prey of fur seals showed a spatial segregation, with prey from southern Brazil typically enriched in 13 C and depleted in 15 N compared with those from northern Argentina. Most adult male fur seals relied mainly on small pelagic fishes and squid captured on the continental shelf, whereas medium pelagic and demersal-benthic prey played a minor role in the diet. 5. It is concluded that South American fur seals rely on pelagic resources (i.e. small pelagic fish and squid) more strongly than previously thought and that their diet does not reflect the varying abundance of demersal-benthic resources in the area.

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Overlap between pinniped summer diet and artisanal fishery catches in Uruguay

Cited by 36 publications

References 15 publications

Composition and seasonal variation in the diet of the South American sea lion (<i>Otaria flavescens</i>) from Quequén, Argentina

Composition and seasonal variation in the diet of the South American sea lion (<i>Otaria flavescens</i>) from Quequén, Argentina

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

Intensive fishing has not forced dietary change in the South American fur seal Arctophoca(=Arctocephalus)australis off Río de la Plata and adjoining areas

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