Publication Abstract

The concept of fecundity regulation in plaice Pleuronectes platessa L. tested on three Irish Sea spawning populations

J. Kennedy, P.R.Witthames and R.D.M. Nash

The fecundity of Irish Sea plaice between 2000 and 2004 was estimated during the spawning season for fish in the three main spawning areas (Liverpool Bay, Cumbrian coast and western Irish Sea) and one small spawning group on the west coast of the Isle of Man. Fecundity was also estimated during September 2003 and 2004. This was done with the aim of assessing the variability in fecundity between areas and years in the Irish Sea.  It was also to identify when differences in fecundity become apparent in the maturation cycle.  There were variations in fecundity on both the temporal and spatial scale. The greatest variation in fecundity between years occurred in the western Irish Sea whilst there was no variation between years in the south-eastern Irish Sea (Liverpool Bay). There was no difference in fecundity between areas or years during September. The maximum fecundity in plaice is determined by the total weight of the fish at the end of follicle recruitment in the ovary and differences in the fecundity of each population are the result of different levels of down regulation in the period between the end of follicle proliferation and spawning. 

Reference

J. Kennedy, P.R.Witthames and R.D.M. Nash (2007) The concept of fecundity regulation in plaice Pleuronectes platessa L. tested on three Irish Sea spawning populations.  Canadian Journal of Aquatic Science and Fisheries, 64(4): 587-601