Identifying newly spawned female sardines by means of common fisheries data

Abstract

In the present study we provide an alternative to histology means of discerning newly spawned female sardines, i.e., females with intact postovulatory follicles, by means of common fisheries data like sample sex ratio, gonosomatic index, total length, and fat index. Compared to the remaining yolked females, newly spawned females were shown to occur in samples with increased male-ratios, to have lower gonosomatic index, larger body-size and limited visceral fat reserves. Using these variables each yolked female could be classified correctly as newly spawned with an accuracy of 81%.