Etude théorique et pratique de la pêche a la lumière

Light fishing is an extremely old practice. It most likely originates from distant times when a man, using a flaming torch next to a river, realised that fishes gathered next to the lightened bank. After that, night fishing, using a fire-or "clairon"-, developed in France and other countries. Different types of light generators were used: torches, burning coal positioned on a grid at the back of the boat, and more recently acetylene, fuel or propane lamps. Finally, for about a decade, electric generators using different tensions have been tried out to supply reflectors and produce a powerful and continuous brightness. In France, fire fishing has been practiced for a long time by Mediterranean fishers who, having replaced the traditional gillnet-called "sardinal"-by ring nets-called "lamparoos"-, greatly increased the amount of pelagic fish caught, especially sardines. On the contrary, fishers from the Atlantic coast were reluctant to use this method, which they thought, for undefined reasons, was unpredictable. This is the reason why they used, and still mainly use, bait made of salted cod-roe and peanut oil meal to attract sardines before circling them with their nets. The use of such a bait implies important expenses for professionals, all the more that they often need to throw large quantities of salted cod-roe to catch very few fishes. Sometimes, the selling price of the fish does not exceed the price of the bait. In this economic situation, the Institute of Marine Fisheries carried out a study about light fishing and tried to improve its techniques. The practical results of these studies have been the subject of many publications, especially in the "Science et Pêche" journal. Although these researches have not been completed, the numerous experimental fisheries conducted on board our fishing pilot boats since 1957, in collaboration with professionals most of the time, enable us to affirm that light fishing of pelagic species of commercial interest is easily feasible and has excellent performances in the Bay of Biscay. Thus, if it has been observed that light can attract some fishes, one does not really know why and how. Despite numerous on-site or laboratory studies, carried out in different countries, the causes of this attraction are not well-known. Neither are the processes of fish gatherings and their behaviour towards artificial lights of various colours and intensities.