Composição, abundância relativa e distribuição de espécies demersais de profundidade no estado de Pernambuco

Abstract

In order to increase current knowledge about deep water demersal communities, and to generate information to assist in the management of deep water resources. This research aims to investigate the composition, relative abundance and distribution of demersal crustaceans, elasmobranchs and teleosts caught in the upper slope of Pernambuco. The surveys occurred on the "Sinuelo" research vessel, of FADURPE / UFRPE, from October 2014 to March 2018. During this period, 24 cruises and 77 sets were carried out along the upper slope of Pernambuco from 200 to 600 meters of depth. The specimens were collected with two fishing gear: the bottom longline, with small and large hook, and bottom traps, in the models: large, medium, round and cylindrical. In the 77 sets, 1050 animals were collected, which 976 (92.95%) were fished by bottom traps and 74 (7,04%) in the bottom longline. Were catched crustaceans, teleost’s and elasmobranchs. Crustaceans were the most captured group (n= 690, 65,71%), followed by elasmobranchs (n= 261, 24,86%) and teleost’s (n= 99, 9,43%). Analyzing the captures of the bottom traps, the CPUE for the joint species, was higher for the large model, showing no significant differences (Kruskal-Wallis chi-squared= 6,5562, df = 3, p= 0,08747). Among the groups, only the teleosts presented significant differences (Kruskal-Wallis, chi-squared = 9,0063, df = 3, p= 0,02921), being the CPUE of the larger and medium model´s, larger than the round model (Teste de Dunn; p= 0,0303, p= 0,0432). The CPUE of the main species collected was tested among the factors, collection station, depth stratum and month. Plesionika edwardsii was catched in the north station. In the depth strata, it had higher catches in stratum “300-349 m” and throughout the year in June, showing no significant differences in any of the factors. The second most captured was the Bathynomus miyarei, concentrating in the north of Recife, in strata “400-449 m” and “500-549 m”, and in the month April. However, there were no significant differences between the factors. Squalus albicaudus also showed no significant differences in relation to the factors but had the highest catch rates in the north of the state, in depths stratum “300-349 m” and “400-449 m”, in May and August. The most catched teleost fish was the Physiculus kaupi, in the north of the state, in depth stratum “300-349 m” and in the month of April, presenting no significant difference. When analyzing the bottom longline, it is noticed that the small hook had higher catch rates for the joint species, elasmobranchs and teleosts, but did not present significant differences. Among the main catches of the bottom longline, the Squalus mitsukurii had higher CPUE values in the south of Pernambuco, in the strata “400-449 m”, and in the month of August. Like the other species, none of the factors presented significant differences. The Cirrhigaleus asper, was the second most caught, concentrating their catches in the northern state, in strata “300-349 m” and “400-449 m”, in July and November. The factors studied did not show a clear pattern of variation, requiring major research efforts to increase knowledge of the deep water and the individuals who inhabit it.