The connective tissues of fish. II. Gaping in commercial species of frozen fish in relation to rigor mortis

Abstract

Summary. Fish of different species frozen whole, thawed and filleted gape according to the time after death at which they were frozen. Those frozen immediately after death gaped least, a marked increase accompanying the onset of rigor mortis. Thereafter, there was a steady increase in gaping as the fish were held for longer periods in melting ice prior to freezing. the cause of this second type of gaping is unknown. There was a marked difference between species, haddock showing the most gaping and catfish and skate none at all. the three species of flat fish gaped less than the four round fish (apart from catfish) species, which fact may relate to the shape of the fish, especially as the roundest‐bodied of the flat fish, halibut, gaped the most of the group. The site of gaping was identified histologically, and different degrees of gaping are illustrated by means of photographs.