Factors affecting the population status of Guadalupe fur seal, Arctocephalus townsendi (Merriam, 1897), at Isla de Guadalupe, Baja California, Mexico

The aim of this project was to investigate some of the possible causes responsible of the slow growth of the population. Three aspects were investigated: (a) population characteristics (i.e., intrinsic population growth rate, population size, density, etc.), (b) breeding behavior (i.e., tenure, mating success, territorial quality, etc.), and (c) characteristics of the foraging trips to sea (i.e., location, diving behavior, etc.).;(b) The mean adult sex ratio for the population was 1:4 ;Of 102 females, 17 (16.7%) were observed during three consecutive breeding seasons, 37 (36.3%) in two and 48 (47%) in one season.;(c) Females instrumented with Time-Depth-Recorders fed in the California Current south of the island. Round-trip mean distance was 2,375.3 ;(a) The colony grew at 13.7% annually from 1955 to 1993, with a pup production of 15.6% annually. The number of seals was greatest during the breeding seasons of 1991-1993: 5,873 ;Mean dive depth of one female was 16.9 ;The results show that none of these causes was responsible of the slow growth of the population.