A PRELIMINARY UPDATE OF THE ALBACORE TUNA (THUNNUS ALALUNGA) STOCK ASSESSMENT FOR THE NORTHERN ATLANTIC OCEAN USING THE INTEGRATED STOCK ASSESSMENT MODEL, MULTIFAN-CL

3SUMMARY An updated stock assessment for northern albacore was conducted using Multifan-CL. Identical model specification to the assessment in 2007 was used in order to allow comparability between the assessments. Updated information was included for catch and catch at size. Updated effort data was also included where available. Preliminary runs indicated that model outputs were dependant on the version of MFCL used, and so for comparative purposes, the input files used in the 2007 assessment were reanalysed using the newest version of MFCL, the same version used for the updated assessment. In general, the updated model was more pessimistic than the previous assessment calculating higher levels of exploitation and biomass depletion than the 2007 assessment. It is unclear at this stage whether this is a true reflection of the state of the stock, or a result of using incompletely updated information in the assessment. Further model runs will be conducted during the 2009 albacore stock assessment meeting in order to clarify this issue. RESUME