Compte rendu des essais de pêche du Laminaria hyperborea

Introduction During the month of April 1994, the "Ressources Halieutiques de l'Ifremer" laboratory (Ifremer Halieutic Resources) in Brest tested tools to be used for the harvesting of Laminaria hyperborea as requested by Système Bio-Industries. The first results of this trial campaign are as follows: The tools are effective as far as interspecific as well as intraspecific selectivity. Rightly so, Laminaria hyperborea accounts for nearly 100% of the harvest. We also noticed that only large size plants are harvested, commercial harvest is satisfactory in terms of yield. However insufficiencies still remain. Comb efficiency is low, since the actual harvest only represents 10 to 12% of the stipes collected when the machine goes through. This low efficiency is doubled up because of damage to the resource. When the machine goes through, some of the plants are broken and upturned rocks push native species flat to the ground. Flattened or broken seaweeds are not harvested. The percentage of upturned middle size rocks and cobble stones is about ten percent. This direct action to the ocean floor results in frequent damage to the equipment. At the end of the 1994 trials, it became obvious that the tools configured at the time could not be put into service on a regular seaweed field exploitation basis. The "Comité Régional des Pêches"(Regional Fishing Committee) is wishing to extend this first approach related to the exploitation of a new resource. It has given Ifremer the mission to test and validate tools which could be put into service. Mr. J.P. Braud, in charge of raw material supplies for Système Bio-Industries, initiated a reflection group with seaweed harvesters in order to come up with a revised comb design. Those tools work using a pulling action. The main modifications consisted in reducing the weight of the device under water by adding waterproof caissons. Lifting up the structure on pads has been considered in order to reduce plant flattening. Ifremer, suggested the experimentation of a cutting device.