North Atlantic humpback whale abundance and rate of increase four decades after protection from whaling

Humpback whales Megaptera novaeangliae in the North Atlantic Ocean were severely by exploitation. With legal protection since 1955, substantial recovery is likely to have, but information on abundance and rates of increase has been limited. We present an of humpback whale abundance in the North Atlantic Ocean based upon capturerecapture using naturally marked individuals. These data result from a long-term collaborative combining large-scale dedicated projects and incidental data collection, leading to geographical coverage. The application of robust statistical techniques produces estimates greater accuracy and precision than has previously been possible. Abundance estimates ranging 5930 to 12 580 individuals, with coefficients of variation (CVs) from 0.07 to 0.39, were calculated the West Indies breeding population using data from 1979 to 1993. The most precise estimate for West Indies breeding population is 10 752 (CV = 0.068) for 1992 and 1993. Due to application of analytical methods, these estimates are larger and more precise than those previously published similar time periods. The average rate of increase for the West Indies breeding population over 14 yr period was estimated to be 0.031 (SE = 0.005). The best available estimate for the entire North population of humpback whales is 11 570 (95% CI 10 290 to 13 390) based upon samples from1992 and 1993. However, this estimate may be biased downwards to an unknown extent due to in capture probabilities that do not influence the West Indies estimates.