Updated population viability analysis, population trends and PBRs for Hector’s and Maui dolphin
EXECUTIVE SUMMARYUpdated population viability analyses, incorporating the latest abundance and bycatch data indicate that: The estimated population decline for Maui dolphin is 2% per yearThere is a 68% probability that the population is continuing to declineAfter 30 years (6 more surveys) statistical power of detecting this rate of decline would be < 15%Only very large declines (37%) and recovery (45%) would be detectable with 80% statistical power after 30 years (6 more surveys)The level of conservation threat for Hector’s dolphin remains high despite a recent, larger population estimate off the east coast of the South IslandIncreased overlap between dolphins and fisheries, due to more extensive offshore distribution of dolphins off the South Island east coast, more than offsets the apparently higher population sizeThe Hector’s dolphin population has declined 70% over the last 3 generations, exceeding the 50% threshold for EndangeredPopulation declines are predicted to continue under current protection levelsThe results of this research are consistent with:◯ NOAA proposal to list Hector’s and Maui dolphins under the US Endangered Species Act◯ IWC recommendation to ban gillnets and trawling throughout Maui dolphin habitat◯ IUCN recommendation to ban gillnets and trawling throughout Hector’s and Maui dolphin habitat