Unanswered Forum Topics

Entanglements of 31 right whales (Eubalaena glacialis) and 30 humpback whales (Megaptera novaeangliae) in the western North Atlantic were analyzed to identify the parts and types of gear involved. The results indicated that a large number of specific gear types were involved in entanglements. Gear type could not be identified in 20% of entanglements. When gear type was identified, 89% of entanglements were caused by pot and gillnet gear. Pot gear was recovered from both species in equal amounts but gillnet gear was more frequently retrieved from humpbacks compared to right whales.

Risk factors involving ship strikes and North Atlantic right whales were investigated in this study. A multi-sensor digital acoustic recording tag (DTAG) was used to measure the responses of whales to four stimuli: vessel noise, social sounds of conspecifics, and a signal designed to alert whales. Silence was used as the control measure. Testing was conducted in the Bay of Fundy summer foraging region.

Right whale survey data and Canadian fishing gear deployment data were used to estimate the threat of gear entanglement to right whales in the Scotia-Fundy region and the risk of lethal entanglement in the Bay of Fundy and Roseway Basin, Scotian Shelf. The following fisheries were investigated: groundfish and pelagic hook and line, groundfish gillnet, and crab, hagfish and inshore/offshore lobster traps. Groundfish hook and line gear poses the largest threat to right whales during the summer resident period in the Bay of Funday and on Roseway Basin (Critical Habitat).

Two test systems were developed to examine fishing line entanglement injuries in large whales. The systems evaluated straight pull abrasion and oscillatory abrasion in relation to tissue compliance. The straight pull abrasion study was used to measure the depth of epidermal penetration after a unidirectional pull of line over a standard draw-length.