Cephalopod remains from stomachs of sperm whales (Physeter macrocephalus) that mass‐stranded along the Oregon coast

Abstract

AbstractOn 16 June 1979, a herd of 41 sperm whales stranded near the mouth of the Siuslaw River in Florence, Oregon. The stomach contents from 32 whales were collected, identified to the lowest taxonomic level possible, enumerated, and measured. A total of 20,247 cephalopod lower beaks that represented 24 species from 14 different families were recovered. The most numerous species wereHistioteuthis hoylei(25.9%),Taonius borealis(12.9%),Galiteuthis phyllura(11.2%),Gonatopsis/Berryteuthistype (10.9%), andMoroteuthis robusta(10.7%). Reconstructed estimates of mass indicated thatM. robustacontributed almost 50% of the total mass of cephalopods consumed, followed byH. hoylei(19.3%), andT. borealis(7.0%). The most important species in the diet of stranded whales wereM. robusta,H. hoylei,T. borealis,G. phyllura,Octopoteuthis deletron, andGonatopsis/Berryteuthistype. There were significant differences in the diet of males and females, but no differences between sperm whales of different age groups. Overall, sperm whales primarily consumed small cephalopods that were likely eaten south of 45ºN in or near the California Current System. This study provides new estimates of the food habits of sperm whales in the northeast Pacific from one of the largest strandings of this species.