[MARMAM] New publication: Trends in sympatric otariid populations suggest resource limitations in the Peruvian Humboldt Current System

Susana Cardenas scardenas at csa-upch.org
Fri Jun 18 08:01:58 PDT 2021

Dear MARMAM members,

My co-authors and I are pleased to announce our recent publication "Trends
in sympatric otariid populations suggest resource limitations in the
Peruvian Humboldt Current System"


Sympatric species evolve mechanisms to avoid competition and coexist. In
the Humboldt Current System (HCS), populations of South American sea lions
(SASL, Otaria byronia) and South American fur seals (SAFS, Arctocephalus
australis) fluctuate mostly due to ENSO events and prey availability. We
evaluate population trajectories of Peruvian sympatric otariids and discuss
mechanisms for competition and/or resource limitation. For this purpose, we
analyzed population trajectories of SASL and SAFS in a sympatric breeding
site in Punta San Juan, Peru between 2001 and 2019. Wavelet analysis was
used to extract trends and derivatives to estimate rates and turning
points. Age-class proportions and biomass times series were constructed
from weekly counts and evaluated. Both populations show a growth phase and
subsequent decline. SAFS started to decline ~2.25 years before and at a
rate 1.5 times faster than SASL. Decrease in juvenile age-class suggests
that resource limitation is the main contributing factor for current
population decline.


Feel free to contact me if you need a copy or have any questions!

Susana Cárdenas Alayza, MSc.
PhD Student
U. Peruana Cayetano Heredia /  Université de Montpellier
Programa Punta San Juan
Centro para la Sostenibilidad Ambiental
Universidad Peruana Cayetano Heredia
¡Síguenos en Facebook! <https://www.facebook.com/ProgramaPSJ/>
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