Open AccessDecoupling of otolith and somatic growth during anadromous migration in a northern salmonid
Author(s) -
Christie Morrison,
Mélodie KunegelLion,
Colin P. Gallagher,
Rick J. Wastle,
Ellen V. Lea,
Tracey N. Loewen,
James D. Reist,
Kimberly L. Howland,
Keith B. Tierney
Publication year - 2019
Publication title -
canadian journal of fisheries and aquatic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 153
eISSN - 1205-7533
pISSN - 0706-652X
DOI - 10.1139/cjfas-2018-0306
Subject(s) - otolith , fish migration , salvelinus , smoltification , decoupling (probability) , biology , life history , trout , environmental science , salmonidae , fishery , ecology , fish <actinopterygii> , salmo , engineering , control engineering
We assessed the fish length – otolith length relationship (FL–OL) in Dolly Varden (Salvelinus malma malma) to verify proportional growth. A decoupling was detected during first ocean migration where fish growth was occurring at a greater rate than otolith growth. Because of this decoupling, the application of traditional back-calculation models overestimated the size-at-age in premigratory char. We developed modified back-calculation equations from existing traditional models to account for this decoupling based on discontinuous piecewise regressions. The new biological intercept breakpoint method (BI–BP) provided the most accurate representation of fish size-at-age throughout all life history stages when compared with known size-at-capture values in fish. The decoupling indicates that factors other than somatic growth are important for otolith accretion. Physiological changes during smoltification likely alter calcium uptake and thereby affect calcium deposition rates on otoliths during this short but biologically critical time period of life history. It is probable that species exhibiting similar complex ontogenetic shifts in life history will likely exhibit decoupling to some extent in the FL–OL relationship.