An application of the annual egg production method to estimate the spawning biomass of cod (Gadus morhua L.), plaice (Pleuronectes platessa L.) and sole (Solea solea L.) in the Irish Sea

The spawning biomass of cod (Gadus morhua), plaice (Pleuronectes platessa) and sole (Solea solea) in the Irish Sea in 1995 was estimated by means of the annual egg production method (AEPM). The area surveyed corresponded to ICES assessment area VIIa. This paper describes the sampling design, methods of analysis, estimates of biomass. and sources of error in the estimates. Estimates are also presented for spatially separated spawning grounds of cod and plaice in the eastern and western Irish Sea, the first time that information at this scale has been available. The AEPM estimates of spawning biomass of cod. sole and plaice exceeded the corresponding estimates from Virtual Population Analysis of data from commercial fisheries and trawl surveys by factors of 2.3,2.7 and 4.3 respectively. The sources of these large discrepancies are not yet resolved.