NOT TO BE CITED WITHOUT PRIOR REFERENCE TO THE AUTHOR(S) Northwest Atlantic Fisheries Organization Serial No. N4758 NAFO SCR Doc. 02/136 SCIENTIFIC COUNCIL MEETING – SEPTEMBER 2002 Approaches to Assessment of Deepwater Sharks in the Northeast Atlantic (Elasmobranch Fisheries – Poster) M. Clarke*, M. Girard + , N.-R. Hareide**, P. Lorance • and R. Officer* (In alphabetical order) *Marine Institute, Abbotstown, Dublin 15, Ireland + PROMA, 6, rue Alphonse Rio, 56323 Lorient, France ** Hareide Fisheries Consultants, Støylerasa 3, Ulsteinvik, Norway • IFREMER/DRV/RH, Centre de Brest, B.P. 70, 29280 Plouzané, France corresponding author M. Clarke, E mail: maurice.clarke@marine.ie Abstract Deepwater sharks are caught in several fisheries in the northeast Atlantic. Among the most important are the Spanish longline fishery, the Norwegian autoline longline fishery and the mixed-species trawl fishery, mainly prosecuted by French vessels. The main species exploited are Centrophorus squamosus and Centroscymnus coelolepis. These fisheries are difficult to assess because accurate time series of catch and effort are collected only by France, and in that instance only for both commercial species combined. Two approaches have been taken to stock assessment of these commercial deepwater shark species: Schaefer production model and Leslie depletion model. The deficiencies in the knowledge base are highlighted and future data and model requirements are discussed. Introduction There are several fisheries for deepwater sharks in the northeast Atlantic, but most activity takes place in the Rockall Trough, and on the slopes of the Porcupine Bank. Two species of sharks are routinely landed for their flesh and livers; the leafscale gulper shark Centrophorus squamosus (Bonnaterre, 1788) and the Portuguese dogfish Centroscymnus coelolepis (Bocage and Capello, 1864). These species are collectively called “siki” in French fishery records (Gordon, 1999) though they are marketed elsewhere under this name too. French vessels catch these species in the mixed-species trawl fishery. Spanish longliners target deepwater sharks too (Pineiro et al ., 2001) but it is difficult to quantify landings as separate statistics for deepwater shark species are not collected from these vessels. More recently, longliners from Norway and Ireland and trawlers from Scotland and Ireland are catching these species. There have been landings of sharks in Sub-area VIII, but the deepwater component is unknown. There are directed gillnet fisheries in this area for sharks also, but little data are available. Table 1 presents landings data for large squalid deepwater sharks, mainly C. squamosus and C. coelolepis and other sharks, some of which are deepwater species. Portugal collects species-specific landings data from artisanal longline fisheries in Div. IX a. More details of these fisheries are given by Figueiredo et al. (this proceedings). In Sub-area X (Azores, Portugal) there was a directed longline fishery for D. licha and details are contained in (Machado et al ., this proceedings). The present work details results of assessments of the two species that are commercially important in the northern part of the ICES area (Sub- areas V, VI, VII, VIII and XII), C. squamosus and C. coelolepis.