History, migration and present status of humpback whales Megaptera novaeangliae at Bermuda

Abstract

Historical accounts show that humpback whales Megaptera novaeangliae have frequented Bermuda waters, which are located half-way between wintering and summering grounds in the western North Atlantic, since the early 17th century. There were more humpbacks present in the 17th, 18th and 19th centuries than there are today. It also appears that humpback whales utilised the Bermuda area from February to May during these centuries, while today they occur at Bermuda for only three to four weeks in April. Humpbacks probably used Bermuda as a breeding ground in winter during these previous centuries and it may be an area that will be repopulated during winter if and when the population recovers from over-hunting. Using the distinctive pattern of pigmentation on the under-sides of the tail flukes, 104 individual humpback whales were identified at Bermuda and 44 of these have also been seen at other locations, including all the major summering and wintering grounds in the western North Atlantic. Chi-square analysis of these resighting shows that the whales occur at Bermuda in the expected proportions, relative to the samples, from the summering and wintering grounds. Contemporary utilisation of Bermuda by humpbacks is as a mid-ocean habitat through which all members of the western North Atlantic population migrate during spring. There is also evidence suggesting that humpback whales feed at Bermuda on deep water scattering layers during their stop-over.