Dahlheim et al.: Interactions, injuries, and mortalities of Orcinus orca during fishing operations 91 
primarily of other marine mammals, 
we suggest that these whales were fol- 
lowing pinnipeds (e.g., Steller sea lions, 
Eumetopias jubatus) that were in turn 
attracted to Alaska BSAI pollock trawl- 
ing operations. The only photographs 
of transient killer whales collected by 
observers were taken when transient 
killer whales were killed and brought 
on board the vessel. Because transient 
whales are not targeting fish, their 
approaches may not be close enough 
to the boats to make it possible to take 
photographs usable for identification of 
ecotype. 
It is unusual to find the large number 
of floating, dead killer whales encoun- 
tered by observers because this species 
is thought to typically sink at death, 
preventing recovery. That a dead killer 
whale is found floating may indicate 
Figure 9 that the whale was recently killed (e.g., 
Photograph of a deceased adult male killer whale (Orcinus orca) entangled in a whale entangled in gear and subse- 
longline gear (whale ID AK218; see Dahlheim, 1997) in the Bering Sea, taken quently drowned) and then tossed back 
during fishing operations in 2007. into the sea. Hence, mortalities could be 
as high as 43 individuals for this study 
period if the 16 killer whales found 
dead prior to fishery interactions are 
determined through genetic analysis were of the resi- added to the 27 killer whales listed as killed as a result 
dent ecotype. However, the 3 killer whales killed in net of interactions. 
entanglements in the Alaska BSAI pollock trawl fishery, The Alaska groundfish fisheries operate in areas where 
all juveniles, were found to be of the transient ecotype. killer whales are known to concentrate (Braham and 
Given that the diet of transient killer whales consists Dahlheim, 1982). Major runs of salmon (Oncorhynchus spp.) 
Table 2 
Details about observations of killer whales (Orcinus orca) entangled in gear and subsequently released and their 
level of injury recorded between 2004 and 2013 in various Alaska Bering Sea and Aleutian Islands fisheries. 
Year Fishery Comments Level of injury determined 
2004 ~=Flatfish trawl Caught in net, released by crew, and swam away. No Detailed data not available; 
injury noted, and no gear trailing. therefore, level of injury 
listed as undetermined. 
2012 ~=Filatfish trawl | Caught in codend. Tried to unzip codend at least Serious injury concluded. 
2 times, but whale’s fins caught in net. Finally cut 
whale free. Blood observed on deck, but unsure of 
level of injury. Whale swam away free of gear. 
Pacific cod Tangled in longline gear. Crew attempted to untangle = Whale not seriously injured. 
longline and cut off groundline. By the time crew got to the 
other end to view the animal, whale had untangled 
itself and swam off. No injury witnessed. 
Flatfish trawl Large orca caught in net. Took a bit of time to Serious injury concluded. 
untangle. Whale appeared stunned or shocked, but 
once back in water it eventually swam back with 
other whales and was free of gear. 
Flatfish trawl Small orca caught in net. Crew cut the net open on Serious injury concluded. 
deck and pushed whale back in water. Whale swam 
off and back to the pod. No gear trailing. 
