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Identifying critical habitat of the endangered vaquita ( Phocoena sinus ) with regional δ 13 C and δ 15 N isoscapes of the Upper Gulf of California, Mexico
Author(s) -
RodríguezPérez Mónica Y.,
AuriolesGamboa David,
SánchezVelásco Laura,
Lavín Miguel F.,
Newsome Seth D.
Publication year - 2018
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/mms.12483
Subject(s) - zooplankton , ecology , environmental science , endangered species , habitat , population , oceanography , geography , biology , geology , demography , sociology
The vaquita ( Phocoena sinus ) is the world's most endangered cetacean and has experienced a 60% reduction in the size of its population in the past decade. Knowledge of its basic ecology is essential for developing successful management plans to protect and conserve this species. In this study, we identified vaquita foraging areas by creating an isoscape of the Upper Gulf of California (UGC) based on sediment and zooplankton carbon ( δ 13 C) and nitrogen ( δ 15 N) isotope values. Our results confirm that this species is confined to the western region of the UGC, which is characterized by relatively high δ 15 N values (sediments: 10.2‰ ± 2.0‰, zooplankton: 15.8‰ ± 1.3‰), higher sea surface temperatures (∼16°C–25°C), higher concentrations of silt in sediments, and the highest turbidity. In contrast, the eastern region of the UGC had relatively low sediment (7.7‰ ± 2.4‰) and zooplankton (14.6‰ ± 1.0‰) δ 15 N values, and the highest concentrations of sand in sediments. Our approach is an effective use of marine isoscapes over a small spatial scale (<200 km) to identify the environmental characteristics that define the critical habitat for an extremely endangered marine mammal.