Hábito alimentar da magumba, hilsa kelee - cuvier, 1829, na Baía de Maputo

Abstract

The present work studied the diet of magumba (Hilsa kelee) captured by the artisanal gill net trawl fishery in Bafa de Maputo. The study lists the specific composition of food items found in the stomachs of 204 fish, 71 adults and 31 juveniles from each fishing zone (Xefina and Machangulo); The study compared diet in terms of abundance, occurrence and dominance between adults from the two zones, juveniles from both zones, as well as between adults and juveniles in each fishing zone. The magumba diet overlap was also qualitatively compared using the x2 test for abundance and the Horn overlap index was used. Of the 20400 food items registered, 26 genera and 1 family were identified. The diet was heterogeneous, being dominated by diatoms, of the genera Biddulphia, Coscinodiscus and Stephanopyxis. Overall for the Xefina zone, Coscinodiscus (31.48%) was the most abundant item, followed by Biddulphia (15.5%), Actinoptychus, Biddulphia, Coscinodiscus, Navicula, Stephanopyxis, Ceratium, Acantharia and Copepocfe were the most frequent and Coscinodiscus the dominant item . In Machangulo, abundance was higher for Stephanopyxis (58.3%), the most frequent being Biddulphia, Coscinodiscus, Paralia, Pleurosigma, Stephanopyxis, Perídinium, Radiolaria and Copepode, the dominant item was Stephanopyxis (72.6%). From a general point of view, all items occurred in both zones, except the Nematodes that did not occur in the stomachs of individuals from Machangulo. The structure of the population under study showed the existence of two cohorts, and an increase in the size of individuals compared to the same period in 1995. Xefina had the smallest captured individual (11.2 cm) and in Machangulo the largest (19.6 cm) was captured. It is concluded that there are differences in the diet of the Xefina and Machangulo magumba, as well as between adults and juveniles, which are probably a result of the species' behavior.