Longlining for tuna

In 1999 the so-called Italian technique of surface longlining for tuna was tested for technical feasibility and economic viability by the Crésus. The technique was originally designed for catching large bluefin tuna, and involved mounting the gear in open water; gradually, however, finer surface mounting was introduced to catch long-finned tuna. Yields of long-finned tuna are better, and catches are more stable over time. Experimental longlining for bluefin tuna continued in parallel, so that the two techniques could be compared. The Crésus ran this experiment in the southern Bay of Biscay from August to October 1999. The work led to estimates of the depth at which hooks were effective, depending on the conditions; it also enhanced experience of operating the gear, and provided information on how the fish reacted (bait, time of catch, effective depth and temperature for hooks, etc.). The quality of the fish caught using this method was assessed, especially in terms of its suitability for the Japanese market, which has been identified as a promising outlet. The exercise was financed by the European Union (Pesca programme), the Aquitaine regional council, the general council of the department of Pyrénées Atlantiques, the regional committee for sea fisheries, the Bayonne local committee for sea fisheries, the professional association Bascopêche and Ifremer.