[MARMAM] New article: Ontogenetic dietary changes in male South American fur seals in Patagonia

Damian Vales damianvales at hotmail.com
Fri Apr 10 10:35:56 PDT 2015


Dear MARMAM members,
We are pleased to announce the following publication:

Vales DG, Cardona L, Garc¨ªa NA, Zenteno L, Crespo EA (2015) Ontogenetic dietary changes in male South American fur seals Arctocephalus australis in Patagonia. Marine Ecology Progress Series 525: 245¨C260 (DOI: 10.3354/meps11214).

ABSTRACT
This
 study assessed ontogenetic dietary changes in male South American fur 
seals Arctocephalus australis in northern and central Patagonia 
(Argentina) using stable isotope ratios (¦Ä15N and ¦Ä13C) in vibrissae and
 bones. Sucking pups were characterised by higher ¦Ä15N values and lower 
¦Ä13C values than older specimens. Weaning was associated with a marked 
drop of ¦Ä15N values, both in bone and vibrissae. Such a drop was 
inconsistent with the consumption of local prey and may reveal movement 
to distant foraging grounds or physiological changes associated with 
either fasting or rapid growth. Stable isotope ratios indicated that 
juveniles fed more pelagically than subadults and adults, but that there
 were no major differences between the 2 latter age categories. As 
subadults and adults are rather similar in body mass and are much larger
 than juveniles, body mass may play a role in the ontogenetic dietary 
changes reported. Nevertheless, demersal benthic prey were always scarce
 in the diet of male fur seals, which relied primarily on Argentine 
shortfin squid and small pelagic fish throughout life, though adults 
also consumed large amounts of decapod crustaceans available at shallow 
depths. Vibrissae did not reveal regular oscillations of ¦Ä15N or ¦Ä13C, 
except in 1 individual. Thus, male fur seals from northern and central 
Patagonia do not appear to migrate regularly between isotopically distinct areas, although nomadic displacements cannot be ruled out.

The paper is available online at http://www.int-res.com/abstracts/meps/v525/ or PDF requests can be sent to vales at cenpat-conicet.gob.ar

Best regards,
Dami¨¢n

-------------------------------------------------------------------------
Dami¨¢n G. Vales
Doctor en Ciencias Biol¨®gicas
Laboratorio de Mam¨ªferos Marinos
Centro Nacional Patag¨®nico (CENPAT)
Consejo Nacional de Investigaciones Cient¨ªficas y T¨¦cnicas (CONICET)
Boulevard Brown 2915,
9120 Puerto Madryn, Argentina
Tel:         54 (280) 4883184  Int 1252
Fax:        54 (280) 4883543
E-mail:    vales at cenpat-conicet.gob.ar
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