Island Ecology

Professor of Biology
Institute of Marine Science
University of California, Santa Cruz

Project Summary:

The aim of this research is to determine existing residue loads of DDT and its metabolites and PCBs in California sea lions. Values obtained will be compared to those obtained during the early 1970's in southern California, central California and Mexico, a time when these contaminants in sea lions was extraordinarily high.

It is important to continue to monitor organochlorine contaminants in the environment since these effects are long lasting. Sea lions, being top-trophic level predators, tend to accumulate these contaminants especially in blubber. If sea lions continue to have heavy loads of these contaminants, they could have an adverse effect on animals and birds that scavenge on the carcasses.

Scott Davis, a graduate student assisting Dr. LeBouef, records pertinent data for each specimen collection © 2000 Frank Starkey/SCIC	Scott Davis makes an incision to remove a plug of blubber © 2000 Frank Starkey/SCIC

My aim is to collect blubber tissue samples from dead sea lions, Zalophus californianus. On Santa Catalina Island, dead sea lions are most likely to be found near sea lions hauling-out or resting spots such as near Seal Rocks on the southeast end, pinnacle on the other side of the island from Avalon, and possibly on the far west end. From previous counts of sea lions on the island, Seal Rocks appears to be the most likely place to find dead sea lions.

A small plug of blubber (about 50 grams) from the dorsum or ventrum at the level of axilla (depending on the orientation the carcass and the willingness of the collector to handle it) will be dissected out, wrapped in tinfoil, and refrigerated. If possible, a single canine tooth will be extracted for aging the specimen. The specimen will be described with respect to sex, age, state of decomposition, location, date and time of collection.