Estudo da comunidade Ictiológica e dieta dos peixes do Saco da Ilha de Inhaca

Abstract

The present work was done in Saco da Inhaca, describes the specific composition, biomass, size (length) and food diet. Trawls were carried out during spring tide, dead tide and at night, using a demersal trawl with a conical shape and rod dimension of 0.5 cm mesh, 2m mouth opening diameter; and coupled to a pulley and an electronic distance counter. The electronic distance counter registered the highest rotations in the sandy habitat and the lowest in the muddy ones, and consequently the largest area fished was the sandy habitat and the smallest was the muddy one. 5911 specimens corresponding to 71 species were captured. The species Oligolepsis keiensis, Amoya signatus and Siiago sihama are the most abundant in all habitats. The largest biomass of fish is in the channel habitat (110.32 g/100m2) and sandy (5.07 g/100m2) with the smallest contribution of biomass. The total biomass of the island was 256921.97 g/100m2. A total of 143 stomachs were analyzed to study the diet, distributed as follows: Live tide = 19, Dead tide = 29, Night = 93 . A total of 222 food items were recorded during laboratory analyses. The fish diet consisted of categories such as Bentos, Necton, Vegetables, Zooplankton and others unidentified. The largest contribution came from Bentos (66.5%) and the smallest from zooplankton (0.6%). The total consumption of fish by habitats in the different categories per gr/100m2/year it was found that the channel habitat offered the greatest amount of food items, with Bentos in the foreground. As for food preference, it was found that fish eat more during the spring tide and in the channel habitat. The organic biomass (AFDW) in Saco da Inhaca is equal to 49380.39 gr/100m2. Higher values ​​were found in the Muddy and Sandbank habitat. There is a relationship between benthic biomass and fish biomass and it was found that the presence of benthic fauna attracts the presence of fish fauna.