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This Working Document summarises the results of applications of the Annual Egg Production Method (Armstrong et al. 2001, Armstrong and Witthames 2012) to estimate spawning stock biomass of cod and plaice in the Irish Sea in 1995, 2000, 2006, 2008 and 2010, and haddock in 2006, 2008 and 2010. This work is conducted jointly between Cefas and AFBI (Belfast). The Marine Institute (Galway) assisted with fecundity estimates in surveys up to 2008.

Using data from mark recovery and electronic tag studies, we investigate the exchange of cod between three adjacent cod management areas; the Irish Sea (ICES Division VIIa), Scottish waters (ICES Division IVa) and in the western English Channel and Celtic Sea (ICES Divisions VIIe-k). We evaluate 2209 archived and current mark recovery data (1960’s – to 2010) to assess the seasonal changes in distribution of cod within ICES Divisions VIa, VIIa and VIIe-g. In addition, we report on the results of a collaborative electronic data storage tagging (DST) programme of cod in the Irish and Celtic Sea, spanning the years 1999 to 2010. During this time, 710 DSTs have been deployed on cod between 43cm and 110cm, and 107 of the tags have been returned yielding over 11000 days of data. We use a tidal geolocation model to determine the daily locations of each cod to reconstruct in detail the migrations of cod tagged with DSTs. The results describe fundamental features of cod spatial ecology in the Irish and Celtic Sea, such as the seasonality of migration and habitat occupation and the potential impact upon sub-stock structure.

This Working Document is derived from a draft Fisheries Science Partnership report currently in preparation, for use by the ICES Working Group on the Celtic Seas Ecoregion. The results are not to be cited without permission from the primary author. The final report will eventually be published on the Cefas web site. The Irish Sea roundfish survey was developed in 2003 as a fully collaborative project between the fishing industry and Cefas scientists. It forms part of the UK Fisheries Science Partnership funded by the UK’s Department for Environment, Food and Rural Affairs (Defra). The scope of the FSP programme, and reports for all completed projects, are available on the FSP page of the Cefas web site. The main objective of the Irish Sea roundfish survey is to develop a time-series of data to track year-on-year changes in abundance, population structure and distribution of the target species (cod, haddock and whiting). The results of the surveys provide information supporting the scientific assessment of the stocks and the management of the fisheries in the Irish Sea. Results of the surveys have been provided annually to WGCSE, and this WD is the same as provided to WGCSE 2011 and has not been updated to include the stock trends from the WGCSE 2011 assessments.