Effects of freezing on length and mass measurements of Atlantic cod Gadus morhua in the Baltic Sea

Abstract

An aggregated sample of 925 Atlantic cod Gadus morhua collected by four countries in different regions of the Baltic Sea during different seasons were measured (total length, L-T = 161-890mm and weighed (mass, M = 45-6900g) both before freezing and after defrosting. The cod were found to decrease significantly in both L-T and M following death and frozen storage. There was an average (+/- SD) change in L-T of -2.91% (+/- 0.05%) following freezing, independent of starting L-T. Total M changed by -2.65% (+/- 0.14%), independent of starting mass. Shrinkage of L-T and M did not differ significantly between 1 and 4 months frozen storage, though L-T shrinkage was significantly greater after 1 or 4 months in the freezer compared with after 5days. There was significant variation in L-T and M shrinkage between regions of capture. A significant negative relationship between condition of cod and L-T or M change was also observed. Equations to back-calculate fresh L-T and M from thawed L-T, M and standard length (L-S), gutted L-T, gutted L-S and gutted M are provided.

Keywords

Baltic Sea; cod; freezing; Gadus morhua; measurement bias; shrinkage

Published in

Journal of Fish Biology
2019, volume: 95, number: 6, pages: 1486-1495
Publisher: WILEY

SLU Authors

• Hilvarsson, Annelie

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

• Casini, Michele

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

• Mion, Monica

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Fish and Aquacultural Science

Publication identifier

• DOI: https://doi.org/10.1111/jfb.14171

Permanent link to this page (URI)

https://res.slu.se/id/publ/102796