Photo: Katie D'Innocenzo © The Marine Mammal Center
While it’s been a tough year for marine mammals along the California coast, local San Francisco Bay conditions may have afforded scientists a unique opportunity to study emerging ocean problems.
The Marine Mammal Center participated in 12 necropsies of deceased gray whales in and around the Bay. Later in the year, malnourished Guadalupe fur seals stranded along the coast at a historically high rate. In June, a surprisingly early toxic algae bloom off the coast of San Luis Obispo caused a rash of cases of Domoic Acid Toxicity among pregnant and yearling California sea lions. Dr. Cara Field, staff veterinarian at The Marine Mammal Center, has some theories as to why these events have occurred. Whale necropsies showed significant emaciation, consistent with studies done on gray whales in Mexico this past winter showing that many were already in poor body condition after returning from their summer feeding grounds in the Arctic. Guadalupe fur seals may be starving due to changing prey patterns, or attempting to return to their historical range. The algae bloom could be related to higher water temperatures, or to the higher than average rainfall last winter. “The fact that previous patterns have changed suggests something is changing,” says Dr. Field, “but we don’t know exactly what yet.” Meanwhile, there are signs that a healthier Bay ecosystem
may be attracting marine life with fresh vigor. Humpback whales were sighted feeding within the Bay this past spring, something Dr. Field says wouldn’t have been seen 20 years ago. The animals that die here afford a valuable opportunity to conduct research and continue to shed light on distant ecosystems. “It’s so important that we continue to gather data from these stranded animals so that we can apply it to bigger picture ocean issues
,” says Dr. Field. “We can’t just focus on local occurrences.”