Diet of California sea lions, Zalophus californianus, at San Jorge Island, northern Gulf of California, Mexico, 1998–1999

The California sea lion, Zalophus californianus (Lesson, 1828), is the only resident pinniped in the Gulf of California, the largest populations inhabiting the Midriff islands and the northern gulf. San Jorge Island, in the northern gulf, has the second largest reproductive colony, and it is genetic...

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Bibliographic Details
Published in:Ciencias Marinas
Main Authors: Eric Mellink, Adriana Lucía Romero-Saavedra
Format: Article in Journal/Newspaper
Language:English
Spanish
Published: Universidad Autónoma de Baja California 2005
Subjects:
Online Access:https://doi.org/10.7773/cm.v31i2.57
https://doaj.org/article/9b5ef747a56e4952bdc63f4e51ecad2a
Description
Summary:The California sea lion, Zalophus californianus (Lesson, 1828), is the only resident pinniped in the Gulf of California, the largest populations inhabiting the Midriff islands and the northern gulf. San Jorge Island, in the northern gulf, has the second largest reproductive colony, and it is genetically different from other colonies in the gulf. We studied the diet of the San Jorge sea lions through scat analysis from February 1998 to March 1999. Midshipman, Porichthys sp. (mostly darkedge midshipman, P. analis Hubbs and Schultz, 1939) was the most important prey item for sea lions at San Jorge, followed by Panama grunt, Pomadasys panamensis (Steindachner, 1875), and Panama brief squid, Lolliguncula panamensis Berry, 1911. It appears that the sea lions foraged mostly on the sea bottom. The prey consumed by sea lions at San Jorge are of no commercial interest. There was little dietary overlap between California sea lions and brown boobies, Sula leucogaster (Boddaert, 1783), the most abundant ichthyophagous bird on the island.