Proceedings of the Vertebrate Pest Conference

Since the Marine Mammal Protection Act (MMPA) of 1972 became a law, many pinniped populations have increased and expanded their range along the west coast of the United States (e.g., California sea lion, Pacific harbor seal, northern elephant seal, northern fur seal, Steller sea lion, etc.). Pinnipeds live primarily in the ocean but rely on coastal areas for important components of their existence (i.e., pupping and resting). As pinniped populations increase along the California coast, numbers of animals hauling out on beaches, rocky substrates, and non-traditional areas such as marinas, docks, and bait receivers have also increased. Confrontations between humans and pinnipeds are escalating. The National Marine Fisheries Service is assigned by the Federal Government to actively manage these species and their interactions with humans. These confrontations have been, in part, a result of competition between people and pinnipeds for prime coastal areas/habitat. The human responses to these interactions have included modification of marine areas used by these animals, but have also included harassment that can lead to injury or death of the animals. Pinnipeds, however, are fully protected from harm under the MMPA. The MMPA Amendments of 1994 provided new authority to citizens of the United States to deter marine mammals from damaging private property, endangering public safety, or damaging public property. A number of non-lethal deterrence methods exist, including physical barriers such as fences and negative stimuli such as sprinkler systems, rubber shot, and acoustics. In most cases, seals and sea lions become habituated to deterrence methods over time. We discuss preliminary results of the use of non-lethal techniques along the coast of California to exclude seals and sea lions from hauling out on marinas, docks, and bait receivers. Preliminary observations indicate that the placement of physical barriers and sprinkler systems has resulted in consistent non-lethal deterrence of sea lions from bait receivers and docks.