Spawning trout Salmo trutta L. populations in the Cummeragh System, Co. Kerry

Abstract

Concentrations totalling more than 300 spawning trout from five sites at three parts of the Cummeragh system were examined in 1980. The majority of the fish were sea trout but some brown trout and precocious males occurred at every site. Of the various physical characteristics of the sites, numbers of fish displayed the most consistent relationship with the volume of water in the pools where they occurred. Trout ranged from 22cm to 68cm fork length and maiden fish of two sea summers comprised the majority. Brown trout matured at a smaller size and younger age than sea trout. Males matured before females and older smolts before younger. Females outnumbered males in the entire collections although there were differences in this and other characteristics of the fish from one site to another, a result it is thought of the timing of sampling. The majority of male sea trout had a brown livery and more female than male trout displayed scars on the body behind the dorsal fin.