DOMOIC ACID CAUSES REPRODUCTIVE FAILURE IN CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS)

Abstract

Exposure of marine mammals to toxins can influence their survival and reproduction. A number of marine mammal mortality events have been attributed to naturally occurring algal toxin exposure, including deaths of manatees (Trichechus manatus latirostris) in Florida due to brevetoxin exposure (O’Shea et al. 1991, Bossart et al. 1998), Hawaiian monk seals (Monachus schauinslandi) due to ciguatoxin (Gilmartin et al. 1980), humpback whales (Megaptera novaeangeliae) due to saxitoxin (Geraci et al. 1989), and California sea lions exposed to domoic acid (DA) (Scholin et al. 2000). Although anthropogenic toxins have been shown to reduce reproductive success in marine mammals (Reijnders 1986) and mortality of marine mammals due to exposure to a variety of marine biotoxins is becoming increasingly recognized (Van Dolah 2000), effects of biotoxins on reproduction have not been reported to date. DA is a potent excitatory neurotoxin produced by marine diatoms in the genus Pseudonitzschia that can affect humans and marine mammals (Perl et al. 1990, Van Dolah et al. 2003). Large-scale mortality of California sea lions has occurred after ingestion of prey that fed on toxin-producing algae (Scholin et al. 2000). DA-producing algal blooms have increased on the west coast of the United States in