Change in the foraging strategy of female South American sea lions (Carnivora: Pinnipedia) after parturition

Abstract Physiology places constraints on an animal’s ability to forage and those unable to adapt to changing conditions may face increased challenges to reproduce and survive. As the global marine environment continues to change, small, air-breathing, endothermic marine predators such as otariids (fur seals and sea lions) and particularly females, who are constrained by central place foraging during breeding, may experience increased difficulties in successfully obtaining adequate food resources. We explored whether physiological limits of female otariids may be innately related to body morphology (fur seals vs sea lions) and/or dictate foraging strategies (epipelagic vs mesopelagic or benthic). We conducted a systematic review of the increased body of literature since the original reviews of Costa et al. (When does physiology limit the foraging behaviour of freely diving mammals? Int Congr Ser 2004;1275:359–366) and Arnould and Costa (Sea lions in drag, fur seals incognito: insights from the otariid deviants. In Sea Lions of the World Fairbanks. Alaska Sea Grant College Program, Alaska, USA, pp. 309–324, 2006) on behavioural (dive duration and depth) and physiological (total body oxygen stores and diving metabolic rates) parameters. We estimated calculated aerobic dive limit (cADL—estimated duration of aerobic dives) for species and used simulations to predict the proportion of dives that exceeded the cADL. We tested whether body morphology or foraging strategy was the primary predictor of these behavioural and physiological characteristics. We found that the foraging strategy compared to morphology was a better predictor of most parameters, including whether a species was more likely to exceed their cADL during a dive and the ratio of dive time to cADL. This suggests that benthic and mesopelagic divers are more likely to be foraging at their physiological capacity. For species operating near their physiological capacity (regularly exceeding their cADL), the ability to switch strategies is limited as the cost of foraging deeper and longer is disproportionally high, unless it is accompanied by physiological adaptations. It is proposed that some otariids may not have the ability to switch foraging strategies and so be unable adapt to a changing oceanic ecosystem.

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Gastrointestinal Parasites and Bacteria in Free-Living South American Sea Lions (Otaria flavescens) in Chilean Comau Fjord and New Host Record of a Diphyllobothrium scoticum-Like Cestode

Frontiers in Marine Science ◽

10.3389/fmars.2018.00459 ◽

2018 ◽

Vol 5 ◽

Cited By ~ 4

Author(s):

Carlos Hermosilla ◽

Jörg Hirzmann ◽

Liliana M. R. Silva ◽

Sandra Scheufen ◽

Ellen Prenger-Berninghoff ◽

...

Keyword(s):

Host Record ◽

Gastrointestinal Parasites ◽

South American ◽

Free Living ◽

New Host ◽

Otaria Flavescens ◽

Sea Lions ◽

New Host Record

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The predation of farmed salmon by South American sea lions (Otaria flavescens) in southern Chile

ICES Journal of Marine Science ◽

10.1093/icesjms/fsp250 ◽

2009 ◽

Vol 67 (3) ◽

pp. 475-482 ◽

Cited By ~ 15

Author(s):

Juan Vilata ◽

Doris Oliva ◽

Maritza Sepúlveda

Keyword(s):

Prey Size ◽

South American ◽

Southern Chile ◽

Otaria Flavescens ◽

Sea Lions ◽

Farmed Salmon ◽

South American Sea Lion ◽

Autumn And Winter ◽

Strong Suspicion

Abstract Vilata, J., Oliva, D., and Sepúlveda, M. 2010. The predation of farmed salmon by South American sea lions (Otaria flavescens) in southern Chile. – ICES Journal of Marine Science, 67: 475–482. The South American sea lion Otaria flavescens is abundant off southern Chile. Because Chilean salmon farming has experienced an explosive growth in the past two decades, interactions between O. flavescens and this industry have increased. Fieldwork, including in situ behavioural observations, was carried out at three salmon farms off southern Chile from May to July 2008. The aim was to analyse possible patterns in the interactions and to evaluate whether they were influenced by the endogenous circa-rhythms of the species, prey size, tidal flux, and the use of an acoustic harassment device (AHD). The results showed that the attacks by O. flavescens followed seasonal patterns, with salmon predated more in autumn and winter, and daily patterns, with more interactions at night. In addition, attacks were more frequent on larger salmon, suggesting the existence of a prey-size preference. More sea lions were sighted at the ebb and flow tide peaks, when currents are stronger, suggesting that currents linked to tidal flux might facilitate the access of the sea lions to the farmed salmon. Although the use of AHDs appeared positive at one site, there is a strong suspicion that their efficacy may be site-specific.

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First observations of operational interactions between bottom-trawling fisheries and South American sea lion, Otaria flavescens in south-central Chile

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315412001282 ◽

2012 ◽

Vol 93 (2) ◽

pp. 489-494 ◽

Cited By ~ 9

Author(s):

Pablo Reyes ◽

Rodrigo Hucke-Gaete ◽

Juan Pablo Torres-Florez

Keyword(s):

South American ◽

The South ◽

Sea Lion ◽

Central Chile ◽

Otaria Flavescens ◽

Sea Lions ◽

South American Sea Lion ◽

South Central ◽

By Catch ◽

Working Day

This paper presents results of a study conducted on the trawling industrial fishery fleet of Merluccius gayi in south-central Chile, and the resulting interactions with the South American sea lion (Otaria flavescens). This study is based on observations made during September 2004, when incidental sea lion catch in the trawls was 6.3 sea lions/working day (1.2 sea lions/trawl−1). A total of 82 animals were incidentally caught, of which 12 were found dead, and the 70 remaining suffered from internal bleeding and/or fractures as a result of their capture. 83.3% of the fatalities occurred during nocturnal trawls, which comprise 30% of all observed trawls. Possible mechanisms of sea lion take are discussed. This note presents the first records of sea lions incidental by-catch by the trawler fleet along the south-east Pacific coast of Chile.

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Factors affecting the operational interaction between the South American sea lions and the artisan gillnet fishery in Chile

Fisheries Research ◽

10.1016/j.fishres.2018.01.014 ◽

2018 ◽

Vol 201 ◽

pp. 147-152 ◽

Cited By ~ 5

Author(s):

Maritza Sepúlveda ◽

Tamara Martínez ◽

Doris Oliva ◽

Pablo Couve ◽

Guido Pavez ◽

...

Keyword(s):

South American ◽

The South ◽

Factors Affecting ◽

Sea Lions

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Changes in the feeding ecology of South American sea lions on the southern Brazilian coast over the last two decades of excessive fishing exploration

Hydrobiologia ◽

10.1007/s10750-018-3618-8 ◽

2018 ◽

Vol 819 (1) ◽

pp. 17-37 ◽

Cited By ~ 5

Author(s):

Rodrigo Machado ◽

Larissa Rosa de Oliveira ◽

Paulo Henrique Ott ◽

Pablo Denuncio ◽

Manuel Haimovici ◽

...

Keyword(s):

Feeding Ecology ◽

Brazilian Coast ◽

South American ◽

Sea Lions

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The northernmost haulout site of South American sea lions and fur seals in the western South Atlantic

Scientific Reports ◽

10.1038/s41598-020-76755-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Natália Procksch ◽

M. Florencia Grandi ◽

Paulo Henrique Ott ◽

Karina Groch ◽

Paulo A. C. Flores ◽

...

Keyword(s):

Mixed Model ◽

Linear Mixed Model ◽

Elephant Seal ◽

Southern Elephant Seal ◽

South American ◽

Mirounga Leonina ◽

Sea Lions ◽

Significant Difference ◽

Northern Portion ◽

Kernel Density Analysis

AbstractWe present estimates of the seasonal and spatial occupation by pinnipeds of the Wildlife Refuge of Ilha dos Lobos (WRIL), based on aerial photographic censuses. Twenty aerial photographic censuses were analysed between July 2010 and November 2018. To assess monthly differences in the numbers of pinnipeds in the WRIL we used a Generalized Linear Mixed Model. Spatial analysis was carried out using Kernel density analysis of the pinnipeds on a grid plotted along the WRIL. Subadult male South American sea lions (Otaria flavescens) were the most abundant pinniped in the WRIL. Potential females of this species were also recorded during half of the census. The maximum number of pinnipeds observed in the WRIL was 304 in September 2018, including an unexpected individual southern elephant seal (Mirounga leonina), and a high number of South American fur seal yearlings (Arctocephalus australis). However, there was no statistically significant difference in counts between months. In all months analysed, pinnipeds were most often found concentrated in the northern portion of the island, with the highest abundances reported in September. This study confirms the importance of the WRIL as a haulout site for pinnipeds in Brazil, recommends that land research and recreational activities occur in months when no pinnipeds are present, and encourages a regulated marine mammal-based tourism during winter and spring months.

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