LESSONS FROM MONITORING TRENDS IN ABUNDANCE OF MARINE MAMMALS

摘要: We assessed scientists’ ability to detect declines of marine mammal stocks based on recent levels survey effort, when the actual decline is precipitous. defined a precipitous as 50% decrease in abundance 15 yr, at which point stock could be legally classified “depleted” under U.S. Marine Mammal Protection Act. for three categories cetaceans: large whales (n = 23, most are listed endangered), beaked 11, potentially vulnerable anthropogenic noise), and small whales/dolphins/porpoises 69, bycatch fisheries important abundant predators), two pinnipeds with substantially different precision: counted land 13) surveyed ice 5), category containing polar bear sea otter 6). The percentage that would not detected was 72% whales, 90% 78% dolphins/porpoises, 5% land, 100% ice, 55% bears/sea otters (based one-tailed t-test, � 0.05), given frequency precision monitoring effort. recommend alternatives improve performance.