Assessing the effects of industrial activity on cetaceans in Trinity Bay, Newfoundland

Borggaard, Diane L. (1996) Assessing the effects of industrial activity on cetaceans in Trinity Bay, Newfoundland. Masters thesis, Memorial University of Newfoundland.

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Abstract

The effects of industrial activity on cetaceans, including humpback whales (Megaptera novaeangliae), minke whales (Balaenoptera acutorostrata), and harbour porpoise (Phocoena phocoena), in Bull Arm, Trinity Bay, Newfoundland during 1992 (Todd et al., 1996), 1994, and 1995 were assessed. Within-year measures of population abundance and distribution, and individual respiration could not detect effects with certainty. These measures were often too variable, too few, or confounded by effects of season and prey distribution. -- Tracking individual animals within years provided some evidence of the short-term effects from industrial activity. In 1994, when dredging was the predominant activity, humpback whales were less likely to be resighted near the industrial activity and exhibited movement away from the site; no such changes were observed during blasting in 1992 (Todd et al., 1996) or during vessel activity in 1995. Humpback resightings and residency were comparatively higher in 1995 than in other years. Furthermore, minke whale resightings occurred in an area of heavy vessel activity in 1995. Reactions by individual cetaceans appeared to depend on the type of industrial activity. -- Resightings of individually identified animals between years suggested long-term effects of industrial activity on cetaceans. Humpback whales photo-identified in Trinity Bay in 1992 were observed less frequently in Newfoundland in 1993 than were whales identified in other inshore bays. In addition, a lower proportion of humpback whales identified in Trinity Bay in 1992 were resighted in Newfoundland in 1993 compared with animals identified in an undisturbed area Individual minke whales were resighted in the industrial area in a subsequent year. Individually identified whales, monitored for several years, were a more sensitive indicator of long-term impacts of anthropogenic activity than abundance, distribution, and respiration measures.

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