Dear colleagues,
We are pleased to announce the publication of a new paper in Deep Sea
Research Part II that may be of your interest.
*Foraging behavior of lactating South American sea lions (**/Otaria
flavescens/**) and spatial-temporal resource overlap with the Uruguayan
fisheries*
Federico G. Riet-Sapriza, Daniel P. Costa, Valentina Franco-Trecu,
Yamandú Marín, Julio Chocca, Bernardo González, Gastón Beathyate, B.
Louise Chilvers, Luis A. Hückstadt
http://dx.doi.org/10.1016/j.dsr2.2012.09.005
ABSTRACT
The negative impacts of the resource competition between fisheries and
marine mammal continue to raise concern worldwide. In order to measure
the impact, data on spatial and dietary overlap of marine mammal and
fisheries are needed. 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 or with the sympatric South American fur seal. Understanding
the extent of the impact of the fisheries overlap or competition for
finite food resources on the sea lion population recovery is necessary
for effective sea lion conservation efforts and fisheries management.
This study aims to determine resource overlap and competition between
South American sea lions (SASL, Otaria flavescens) and the artisanal
fisheries (AF), and the coastal bottom trawl fisheries (CBTF). This is
conducted by integrating 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. Lactating females (n =10) were fitted with satellite tags and
Time-depth recorders. We used kernel (KR) and peeled minimum convex
polygon (95% MCP) methods for estimating the foraging utilization
distribution of lactating SASL. Lactating SASL are benthic divers and
are restricted to forage in shallow waters within the continental shelf.
SASL's foraging areas overlapped with CBTF (15%) and AF (>1%) fisheries
operational areas. In contrast, SASL dietary analysis indicated a high
degree of overlap between the diet of SASL and the AF and CBTF fisheries
catch. The results of this work show differing degrees of spatial
resource overlap with AF and CBTF, highlighting a) differences in
potential impact from each fishery; and b) that different
management/conservation approaches may need to be taken to solve the
fisheries-SASL conflict.
_______________________________________________
MARMAM mailing list
[email protected]
https://lists.uvic.ca/mailman/listinfo/marmam
