Open AccessThe bite force-gape relationship as an avenue of biomechanical adaptation to trophic niche in two salmonid fishes
Author(s) -
Elska B Kaczmarek,
Nicholas J. Gidmark
Publication year - 2020
Publication title -
journal of experimental biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.367
H-Index - 185
eISSN - 1477-9145
pISSN - 0022-0949
DOI - 10.1242/jeb.223180
Subject(s) - bite force quotient , oncorhynchus , biology , sympatric speciation , predation , niche , adaptation (eye) , wing , ecology , anatomy , fishery , fish <actinopterygii> , engineering , aerospace engineering , neuroscience
All skeletal muscles produce their largest forces at a single optimal length, losing force when stretched or shortened. In vertebrate feeding systems, this fundamental force-length relationship translates to variation in bite force across gape, which affects the food types that can be eaten effectively. We measured the bite force-gape curves of two sympatric species: king salmon (Oncorhynchus tshawytscha) and pink salmon (O. gorbuscha). Cranial anatomical measurements are not significantly different between species, however, peak bite forces are produced at significantly different gapes. Maximum bite force is achieved at 67% of maximum gape for king salmon and 43% of maximum gape for pink salmon. This may allow king salmon to use greater force when eating large or elusive prey. In contrast, pink salmon do not require high forces at extreme gapes for filter feeding. Our results illustrate that the bite force-gape relationship is an important ecophysiological axis of variation.