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.
Best regards,
Dami¨¢n
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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) 4883543E-mail:
vales@cenpat-conicet.gob.ar-------------------------------------------------------------------------