The Galapagos Fur Seal is the smallest of all the pinnipeds. It breeds on the Galapagos Islands in the eastern Pacific - making it the only fur seal to breed in tropical waters.
The number of Galapagos Fur Seals successfully bred in a year is very sensitive to El Niņo weather events. In the El Nino summers of 1982-1983 and 1997-1998 greatly increased infant mortality. Increased water temperature decreases the abudance of prey during these summers.
References
Randall R. Reeves, Brent S. Stewart, Phillip J. Clapham and James A. Powell (2002). National Audubon Society Guide to Marine Mammals of the World. Alfred A. Knopf, Inc. ISBN 0375411410.