Biomass, abundance and geospatial distribution estimation of main small pelagic fish in the Gulf of Guayaquil, during October 2013

摘要

From 15 to October 24, 2013, the second hydroacoustic survey cruise T13-10-02P aboard the B/I Tohalli, made with emphasis on small pelagic fish in the Gulf of Guayaquil was ejecuted. The biomass estimated was Auxis thazard 121.976 t, Scomber japonicus 70.818 t, Decapterus macrosoma 23.894 t and Opisthonema spp. 8.613 t; totaling ca. 225.302 tonnes and an abundance of 713.51 million, an increase of 20% and 9% respectively, compared to the results of biomass and abundance of hydroacoustic surveys obtained in February of that year. The small pelagic with greater representation in this study was Auxis thazard, whose biomass was ca. 121.976 tonnes and an abundance of 235 million, showing a greater concentration of individuals to 12 nm offshore opposite the Puntilla Santa Elena. The correlation values found were above n = 0,350 which helped identify areas of species associations. The correlation values and significance show that Scomber japonicus is the resource that shows better affinity between the three variables of analysis (NASC, abundance and biomass) and spatial data. In the study area masses of cold water with southwesterly direction, the temperature was gradually increased from 23 to 24??C, detecting ambient conditions at the time was observed.