Acoustic estimation of Pacific sardine biomass in the Gulf of California during the spring 2008-2012
Résumé
It is necessary to refine the acoustic estimation method applied in the Gulf of California, especially regarding the acoustic energy allocation to the different species coexisting in the same area, in order to produce a more precise and reliable fishery independent biomass index for the sustainable management of the fishery. The series of acoustic surveys carried out in this work are the first systematic attempts to estimate Pacific sardine biomass in the Gulf of California. Due to similar acoustic reflectivity of other pelagic species, we need to refine the allocation of acoustic energy to species. From 2012, besides the 38 kHz transducer another frequency has been incorporated (120 kHz) in the surveys. With both frequencies we will apply acoustic signal filtering procedures in order to 1). Discriminate zooplankton echoes from fish echoes and 2). Investigate the possibility to better discriminate the Pacific sardine from other species.