South American sea lions foraging Uruguay

Federico Riet Sapriza, Proyecto Pinnípedos

Dataset credit

Federico Riet Sapriza, Proyecto Pinnípedos


Primary contact Federico Riet Sapriza Proyecto Pinnipedos, Sección Etología, Facultad de Ciencias, UDELAR
Data entry Connie Kot Duke University



Resource competition between fisheries and marine mammal continue to raise concern worldwide. Understanding this complex conflict requires data on spatial and dietary overlap of marine mammal and fisheries. In Uruguay, the South American sea lions population has been dramatically declining over the past decade. The reasons for this population decline are unknown but may include the following: (1) direct harvesting; (2) reduced prey availability and distribution as a consequence of environmental change; or (3) biological interaction with fisheries. This study aims to determine resource overlap and competition between South American sea lions (SASL, Otaria flavescens, n=10) and the artisanal fisheries (AF), and the coastal bottom trawl fisheries (CBTF). We integrated data on sea lions diet (scat analysis), spatial and annual consumption estimates; and foraging behavior-satellite-tracking data from lactating SASL with data on fishing effort areas and fisheries landings. We found that lactating SASL are benthic divers and forage in shallow water within the continental shelf. SASL's foraging areas overlapped with CBTF and AF fisheries operational areas. Dietary analysis indicated a high degree of overlap between the diet of SASL and the AF and CBTF fisheries catch. The results of our work show differing degrees of spatial resource overlap with AF and CBTF, highlighting that there are differences in potential impact from each fishery; and that different management/conservation approaches may need to be taken to solve the fisheries-SASL conflict.


In this study we hypothesized that the biological interaction between SASL and fisheries may create sub-optimal foraging conditions for lactating females breeding in Isla de Lobos the second largest breeding colony. The objectives of the present study were as follows: (i) to examine the diving behavior of lactating SAS, (ii) to determine the spatial distribution of foraging effort of lactating SASL, (iii) to study the diet of lactating SASL, and (iv) to integrate these data with information of spatial distribution of fishing catch and effort to quantify the trophic and spatial overlap between SASL and the Uruguayan artisanal and coastal bottom trawl fisheries.

Supplemental information

This research was funded by the US Marine Mammal Commission under the Grant no. E4047335 and the Office of Naval Research Grant N00014-08-1-1195, the E&P Sound and Marine Life Joint Industry Project of the International Association of Oil and Gas Producers.

We would like to thanks Nelson Veiga, José Luis Veiga, Gabriel Pereyra, Leonardo Olivera, D.J. Shuman, H. Katz, R. Frau, S. Tavoni, M. García, M. Rivas for their invaluable assistance and collaboration during the field work. We are also thankful to C. Leiza (Parque Zoológico Lecoq, Uruguay) for providing tranquilizing darts dart, and the Marine Mammal Center (Sausalito, California, USA) for lending the capture nets. We would like to acknowledge the logistical support of DINARA. The present work was conducted under the permit #572/208 approved by DINARA (National Administration of Aquatic Resources), Ministry of Livestock, Agriculture and Fisheries, Uruguay.




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Attributes in dataset

Attribute (table column)Description
oidUnique id (created by OBIS-SEAMAP)
obs_dateObserved date
obs_timeObserved time
seriesAnimal ID
device_idPTT #
sexSex of animal tagged
ageAge of animal tagged
sp_obsSpecies tagged
sp_tsnSpecies ITIS TSN
obs_countObserved count of tagged animal = 1
Marine mammals83,233
Sea turtles0
Rays and sharks0
Other species0
Non spatial0
Non species0
Date, Begin2009-01-16
Date, End2009-03-03
Temporal prec.111111
Latitude-36.13 - -34.89
Longitude-55.62 - -53.85
Coord. prec.3 decimal digits
Data typeTelemetry location
TracklinesYES (ID: 898)
Traveled (km)6,058
Travel hours4,402
Contr. through
Sharing policy Permission required
Shared with None
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