Antxoaren maneiu eta kontserbazioa: biomasan eragiten duten faktoreen azterketa

Abstract

The anchovy constitutes one of the most important pelagic fish genera fisheries. Due to several years of low recruitment in the Bay of Biscay, this fishery was closed between the years 2005-2010. To avoid this situation to be repeated in the future, it is important to take into account the population status and other factors involved, such as determining the abundance of big-sized individuals, water currents, predators, parasites and microorganisms causing diseases, river plumes, the structure and diversity of zooplankton (their main food source)… etc. In addition to the previously mentioned variables acting directly on anchovy’s biomass and recruitment, there are also indirect effects caused by other factors, such as those affecting zooplankton. Some examples of these factors are water temperature, phytoplankton, salinity, upwellings… Not considering all of the previously mentioned variables could cause a negative effect on the future biomass of anchovies, therefore their study is much needed.; Antxoa arrantza-munduko genero pelagiko garrantzitsuenetariko bat da. Bizkaiko Golkoan, 2005 eta 2010 bitartean antxoaren arrantza debekatu egin zen aurreko urteetan izandako errekrutamendu baxuak zirela eta. Halakorik errepikatu ez dadin populazioaren egoera eta honi eragiten dioten faktoreak zeintzuk diren jakitea garrantzitsua da; hala nola tamaina handiko indibiduoen kopurua zein den, harrapariak, korronteak, parasitoak, birusak eta bakterioak, ibaien lumak, zooplanktonaren (beraren elikagaia) ugaritasuna eta komunitatearen estruktura/dibertsitatea etab. Antxoaren biomasan (eta errekrutamenduan) zuzenean eragiten duten faktore horietaz gainera, badira zeharkako eragile batzuk ere, antxoaren elikagai nagusia den zooplanktonean eragiten dutenak hain zuzen ere. Adibidez, uraren tenperatura, fitoplanktona, gazitasuna, upwellinga, etab. Eragile horiek kontuan ez hartzeak ondorioak ekarri ditzake etorkizuneko antxoaren biomasan eta, beraz, horiek aztertzea ezinbestekoa da.