ASSESSMENT OF THE APHIA-MINUTA STOCK (PISCES, GOBIIDAE) BY ACOUSTIC METHODS FROM THE BAY-OF-ALCUDIA (MALLORCA, WESTERN MEDITERRANEAN)

Acoustic techniques have been used for the first time to evaluate the abundance and distribution of the Aphia minuta stock (Pisces: Gobiidae ) from the Island of Mallorca (Baleares, Spain). Acoustic surveys have been carried out during three consecutive seasons (1993, 1994 and 199 5) in the more important fishing zone of this island, the Bay of Alcud ia. Indices were obtained for abundance (m(3)) of this goby at the beg inning of the fishing season. The volume of A. minuta has decreased fr om 12,902,751 m(3) in January 1993 to 1,161,248 m(3) in January 1995. The catches obtained have gone from almost six tonnes in 1993 to be pr actically nil in 1995.