Recovery of the South American sea lion (Otaria flavescens) population in northern Patagonia

2004 ◽  
Vol 61 (9) ◽  
pp. 1681-1690 ◽  
Author(s):  
Silvana Laura Dans ◽  
Enrique Alberto Crespo ◽  
Susana Noemí Pedraza ◽  
Mariano Koen Alonso
Keyword(s):  
Survival Rates ◽  
South American ◽  
The South ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
Northern Patagonia ◽  
Rates Of Change ◽  
South American Sea Lion ◽  
Rate Of Increase ◽  
Peripheral Areas

The size of and trend in the South American sea lion (Otaria flavescens) population located in northern Patagonia were estimated and changes in the distribution, size, and structure of individual sites were analyzed during the period 1983–2002. Total counts were made during the reproductive season. Regression models were used to analyze the trend. Pups represented around 40% of the animals counted. The annual rates of change for pups and nonpups were not significantly different (p > 0.05, n = 7), although some rookeries showed higher rates of change for pups than for nonpups. Pup numbers have been increasing at the rate of 3.4% per year at the oldest rookeries, but the rate of increase was higher at new rookeries. Using Bayes' methods, the precision of the estimates and the contribution to the abundance of each rookery produced an alternative estimate of the trend in pup numbers in 5.7%. The key in the recovery of this population includes higher survival rates of juveniles combined with increased available habitat for newly reproducing individuals. This process led to the occupancy of new areas for hauling out and breeding. This hypothesis could explain the higher rates of increase in pups in peripheral areas while reproductive rates remain unchanged.

Small-scale variation in the diet of the South American Sea lion (Otaria flavescens) in northern Patagonia (Argentina)

2019 ◽  
Vol 28 ◽  
pp. 100592
Author(s):  
Dayana Jarma ◽  
María Alejandra Romero ◽  
Néstor A. García ◽  
Guillermo Svendsen ◽  
Raúl González ◽  
...  
Keyword(s):  
Small Scale ◽  
South American ◽  
The South ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
Northern Patagonia ◽  
South American Sea Lion ◽  
Scale Variation

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

2012 ◽  
Vol 93 (2) ◽  
pp. 489-494 ◽  
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.

Redescription of Antarctophthirus microchir (Anoplura: Echinophthiriidae) from the South American Sea Lion, Otaria flavescens, from Patagonia, Argentina

2009 ◽  
Vol 95 (5) ◽  
pp. 1086-1092 ◽  
Author(s):  
M. Soledad Leonardi ◽  
Enrique A. Crespo ◽  
Juan Antonio Raga ◽  
Mercedes Fernández
Keyword(s):  
South American ◽  
The South ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
South American Sea Lion

scholarly journals Interactions between the South American sea lion (Otaria flavescens) and the artisanal fishery off Coquimbo, northern Chile

2008 ◽  
Vol 65 (9) ◽  
pp. 1739-1746 ◽  
Author(s):  
Sabine Goetz ◽  
Matthias Wolff ◽  
Wolfgang Stotz ◽  
Mario J. Villegas
Keyword(s):  
South American ◽  
Northern Chile ◽  
Artisanal Fishery ◽  
The South ◽  
Sea Lion ◽  
Management Options ◽  
Otaria Flavescens ◽  
Sea Lions ◽  
South American Sea Lion ◽  
Fishing Vessels

Abstract Goetz, S., Wolff, M., Stotz, W., and Villegas, M. J. 2008. Interactions between the South American sea lion (Otaria flavescens) and the artisanal fishery off Coquimbo, northern Chile. – ICES Journal of Marine Science, 65: 1739–1746. The South American sea lion (Otaria flavescens) forages in coastal waters, where it interacts with fisheries and causes considerable economic loss by removing some catch and damaging gear. This study describes for the fishery region of Coquimbo (Chile) where, when, and with what type of gear interactions occur, characterizes the animals involved (group size, sex, and age), and derives some management recommendations. The study was based on 55 interviews with fishers and observations aboard fishing vessels in the main fishing sectors between October 2003 and March 2004. Interactions were primarily at night (88% of interviewees fished at night), in the bay (“Bahía”) of Coquimbo (81% of interviewees fished in this sector), where shoaling fish were abundant, and with purse-seines (100% of interviewees used this gear). Although some large groups of sea lions were seen, most comprised 1–10 animals. Most animals that interacted with the fishing gear were males (67%), probably because of the different feeding strategies of the two sexes. Management options discussed include the adjustment of fisheries to foraging behaviour of sea lions, and the controlled elimination of conflicting animals.

scholarly journals Mitochondrial control region haplotypes of the South American sea lion Otaria flavescens (Shaw, 1800)

2010 ◽  
Vol 43 (9) ◽  
pp. 816-820 ◽  
Author(s):  
L.O. Artico ◽  
A. Bianchini ◽  
K.S. Grubel ◽  
D.S. Monteiro ◽  
S.C. Estima ◽  
...  
Keyword(s):  
Control Region ◽  
Mitochondrial Control Region ◽  
South American ◽  
The South ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
South American Sea Lion

Sexual harassment and female gregariousness in the South American sea lion, Otaria flavescens

2008 ◽  
Vol 95 (7) ◽  
pp. 625-630 ◽  
Author(s):  
Humberto L. Cappozzo ◽  
Juan I. Túnez ◽  
Marcelo H. Cassini
Keyword(s):  
Sexual Harassment ◽  
South American ◽  
The South ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
South American Sea Lion

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

2012 ◽  
Vol 102 (4) ◽  
pp. 394-400 ◽  
Author(s):  
Raimundo L. Bustos ◽  
Gustavo A. Daneri ◽  
Alejandra V. Volpedo ◽  
Ana Harrington ◽  
Esperanza A. Varela
Keyword(s):  
Feeding Activity ◽  
Winter Season ◽  
Abundant Species ◽  
South American ◽  
The South ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
South American Sea Lion ◽  
Rio Negro ◽  
Patagonian Coast

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.

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

2014 ◽  
Vol 20 (3) ◽  
pp. 235-243 ◽  
Author(s):  
RL Bustos ◽  
GA Daneri ◽  
AV Volpedo ◽  
A Harrington ◽  
EA Varela
Keyword(s):  
Summer Season ◽  
South American ◽  
The South ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
South American Sea Lion ◽  
Rio Negro
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