High calf mortality in bottlenose dolphins in the Bay of Islands, New Zealand–a local unit in decline

摘要: Bottlenose dolphins (Tursiops truncatus) in the Bay of Islands, New Zealand, have been studied for almost two decades. Since 2003, fewer than 150 visited bay during each season and local unit has declined 7.5% annually from 1997 to 2006. The causes decline are unclear but probably include mortality emigration. Here, we used a long-term database estimate reproductive parameters female bottlenose including recruitment rates. A total 704 surveys were conducted which 5,577 sightings 408 individually identified collected; these 53 individuals as females. calving rate increased between periods (1997–1999 = 0.13, CL 0.07–0.21; 2003–2005 0.25, 0.16–0.35 calves/reproductive female/year). 0.25 suggests that on average, gives birth only once every four years, is consistent with estimated interval (4.3 yr, SD 1.45) still lower values reported other populations. Conversely, apparent rates age 1+ (range: 0.34–0.52) 2+ 0.15–0.59) higher elsewhere. high calf conjunction abundance, highlight vulnerability Islands. Long-term studies required understand abundance. Meanwhile, management should focus minimizing sources anthropogenic disturbance enforcing compliance current legislation.