Estimating sperm whale (Physeter macrocephalus) daily abundance from a shore-based survey within the Kaikoura submarine canyon, New Zealand

The Kaikoura submarine canyon (New Zealand) is one of the few places in the world where male sperm whales (Physeter macrocephalus) can be found year round close to the shore. The objective of this study was to estimate the daily abundance of sperm whale within the study area. Positions of sperm whales were measured from a shore-based station over a 2-year study (2010-2012) which included information from 4613 sperm whale sightings. Distance sampling and mark-resight models were used to estimate daily abundance. Results showed a mean of four (SEM = 0.13) individuals present in the study area at any given time. These results differ from, and are much lower than, those from previous studies. A decline in the daily number of individuals suggests that a cautious management approach is necessary. Our study illustrated the application of distance sampling and mark-resight methods from a shore-based station.