• Evaluation of the Benefits to Sustainable Management of Seasonal Closure of the Greencastle Codling (Gadus morhua) Fishery

      Ó Cuaig, M.; Officer, R. (Marine Institute, 2007)
      The project examined whether the seasonal closure of the traditional cod fishing grounds off Greencastle, Co. Donegal, could be an effective alternative management measure. The project was instigated by the local fishing industry and operated in cooperation between industry, the Marine Institute and Bord Iascaigh Mhara. The main objectives of the project were to demonstrate the change in yield likely to result from seasonal closure, and, to determine the pattern of movement of cod from the Greencastle fishery. Each winter from 2003 to 2005 the fishery was closed by Statutory Instrument. This was achieved with the voluntary commitment of the local industry. During this period over 13,000 cod were tagged and released by Marine Institute and BIM staff working aboard chartered fishing vessels. The closure itself provided a significant conservation benefit. During 2000-2002 50% of the Irish catch weight of cod in Division VIa (> 60% by number) was taken in the winter. The closure will therefore have markedly reduced the fishing mortality on cod that would otherwise have occurred from 2003 to 2005. As the Greencastle codling fishery is a mixed whitefish fishery, any benefits flowing from the closure are likely to have extended to other whitefish stocks. Growth was extremely variable but averaged around 17 cm per annum for cod at liberty for extended periods. During the winter tagging surveys the repeated recapture of recently tagged cod on the grounds indicated the retention of cod on the grounds during winter. Tagged cod at liberty for extended periods were subsequently recaptured on, or near the Cape grounds. This strong fidelity towards the Cape grounds during winter coupled with high growth rates may mean that a short winter fishing season, with a delayed opening, may yield a similar total weight of codling than the traditional fishery but with the catch of a reduced number of cod. Such schemes may reduce current fishing mortality rates. However, the stock status of Division VIa cod is so poor that a complete closure of the fishery is warranted. It is recommended that continuation of the project be considered as a mechanism for maintaining a closure of most of the Irish fishery, whilst simultaneously improving the quality of data available for stock assessment.