Collisions between ships and whales

TL;DR: In this article, the authors search historical records and computerized stranding databases for evidence of ship strikes involving great whales (i.e., baleen whales and the sperm whale).

Abstract: Although collisions with motorized ships are a recognized source of whale mortality, little has been done to compile information on the frequency of their occurrence or contributing factors. We searched historical records and computerized stranding databases for evidence of ship strikes involving great whales (i.e., baleen whales and the sperm whale). Historical records suggest that ship strikes fatal to whales first occurred late in the 1800s as ships began to reach speeds of 13-15 kn, remained infrequent until about 1950, and then increased during the 1950s-1970s as the number and speed of ships in­ creased. Of 11 species known to be hit by ships, fin whales (Balaenoptera physalus) are struck most frequently; right whales (Eubalae1la glacialis and E. allStralis), humpback whales (Megaptera novaeangliae), sperm whales (Physeter catodon), and gray whales (Eschrichtius robustllS) are hit commonly. In some areas, one-third of all fin whale and right whale strandings appear to involve ship strikes. To assess contributing factors, we compiled descriptions of 58 collisions. They indicate that all sizes and types of vessels can hit whales;