Abstract

Scarring resulting from entanglement in fishing gear can be used to examine cetacean fishery interactions. False killer whales (Pseudorca crassidens) are known to interact with the HawaiÔi-based tuna and swordfish long-line fishery in offshore Hawaiian waters. We examined the rate of major dorsal fin dis- figurements of false killer whales from nearshore waters around the main Hawaiian Islands to assess the likelihood that individuals around the main islands are part of the same population that interacts with the fishery. False killer whales were encountered on 11 occasions between 2000 and 2004, and 80 distinctive individuals were photographically documented. Three of these (3.75%) had major dorsal fin disfigurements (two with the fins completely bent over and one missing the fin). Information from other research suggests that the rate of such disfigurements for our study population may be more than four times greater than for other odontocete populations. We suggest that the most likely cause of such disfigurements is interactions with longlines and that false killer whales found in nearshore waters around the main Hawaiian Islands are part of the same population that interacts with the fishery. Two of the animals documented with disfigurements had infants in close attendance and were thought to be adult females. This implies that even with such injuries, at least some females may be able to produce offspring, despite the importance of the dorsal fin in reproductive thermoregulation.

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Additional Information

ISSN
1534-6188
Print ISSN
0030-8870
Pages
pp. 593-601
Launched on MUSE
2005-08-16
Open Access
No
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