Feeding, Social and Migration Behavior of Bowhead Whales, Balaena Mysticetus, in Baffin Bay vs. The Beaufort Sea—regions With Different Amounts of Human Activity

Abstract

This paper compares the behavior of bowhead whales of the Davis Strait/ Baffin Bay stock, as observed along the east coast of Baffin Island in [1979][1980][1981][1982][1983][1984][1985][1986], with behavior of the Bering/Chukchi/Beaufort Sea stock observed in the Beaufort Sea in 1980-1986. All data used here were collected during late summer and early autumn in the absence of acute human disturbance. The behavioral repertoires of the two populations were similar. However, quantitative differences were found for whales engaged in all three activities studied: (1) Bowheads feeding in deep water off Isabella Bay, Baffin Island, had longer dives and surfacings, on average, than noted for bowheads feeding in the Beaufort Sea.(2) Among whales socializing in shallow water, we saw sexual interactions more often at Isabella Bay than in the Beaufort Sea. Calls emitted by socializing whales off Baffin Island were similar to those heard in the Chukchi and Beaufort Seas. However, pulsed tonal calls were longer off Baffin Island, and previously undescribed mechanical "crunch" sounds were recorded there near socializing bowheads. (3) During autumn migration, "fluke-out" dives were less common, and dive durations were longer, in the Beaufort Sea than off Baffin Island (P<O.OOl).Multivariate and other analyses indicated that some but not all differences can be ascribed to regional differences in the natural environment or in whale activities, However, during 1974However, during -1986 Bering/Chukchi/Beaufort bowheads were exposed to more industrial, hunting and other human activity than Davis Strait/Baffin Bay bowheads. The "inconspicuous" behavior during autumn migration in the Beaufort may have been attributable to human activities, but causative links cannot be isolated.

Seismic operations have variable effects on dive-cycle behavior of bowhead whales in the Beaufort Sea

“…Although some of the earliest studies detected subtle differences in dive-cycle behaviors in the presence vs. absence of seismic sounds (e.g. Richardson et al 1986, 1995b, Ljungblad et al 1988), they did not attempt to allow for the confounding effects of other key variables or to account for repeated observations of individual whales.…”

“…However, it is not known how the SRD behavior of bowhead whales is affected by the interaction between naturally varying factors and exposure to seismic and other industry operations. Naturally varying factors include region, whale activity, water depth, reproductive status, and time of year, and these factors are known to influence the SRD behaviors of undisturbed bowheads (Würsig et al 1984, Dorsey et al 1989, Richardson et al 1995b.…”

Marine vessels alter the behaviour of bottlenose dolphins Tursiops truncatus in the Istanbul Strait, Turkey

“…Marine traffic density throughout the Istanbul Strait is exceptionally high and similar di rectional changes and behavioural transitions, i.e. increase in diving behaviour and decrease in bout lengths, have been reported in previous studies (Richardson et al 1995b, Hastie et al 2003, Aguilar Soto et al 2006, Bejder et al 2006a, Neumann & Orams 2006, Christiansen et al 2010, Visser et al 2011, Bas et al 2015, Meissner et al 2015. We therefore suggest that regulations which take into account the speed and distance of the vessels, together with an implementation of 'Particularly Sensitive Sea Areas', play fundamental roles in minimising these negative behavioural effects.…”

Acoustic communication in the North Atlantic right whale (Eubalaena glacialis)

“…Importantly, most species of coastal baleen whales, including bowhead and gray whales, show behaviors that appear to be similar to those observed in the North Atlantic right whale. The SAGs and wuzzles of these two species appear to occur II both the breeding and feeding season, involving multiple individuals and sexual activity, even outside ofthe breeding season when mating for fertilization is thought to take place (Everitt & Krogman, 1979;Norrs et al, 1983, Swarz, 1986Richardson et al, 1995).…”

“…This is a conservative estimate of range of detectability where RL = NL. Animals are often capable of detecting sounds that are received at levels similar to the overall noise levels (Richardson et al, 1995).…”