Report of the Planning Group on North Sea Cod and Plaice Egg Surveys in the North Sea (PGEGGS)

The Planning Group on North Sea Cod and Plaice Egg Surveys in the North Sea (PGEGGS) was set up to address the fact that there had never been a complete ichthyoplankton survey of the North Sea. In particular, the need to monitor commercial fish spawning areas was identified by the Expert Panel which followed the Bergen Ministerial Meeting. Although spawning grounds can be monitored to some extent by adult trawl surveys, ichthyoplankton surveys have a number of potential advantages. Since individual fish spawn thousands of eggs it is often more reliable to sample the eggs rather than the adult fish and surveying spawning grounds of species producing planktonic eggs is also not restricted by bottom-type so a more complete spatial coverage can be achieved. In addition, if the area can be repeatedly surveyed over the spawning period, an estimate of total annual egg production can be made. When combined with fecundity data, such estimates are useful as additional stock assessments and can act as a validation of stock assessments made using standard methods based on commercial fisheries data.Because of the current poor state of the cod and plaice stocks, it was decided to focus on those species. Early on PGEGGS undertook a literature review of all the available historical data in order to inform the design of the North Sea survey.