Comunidade de siris (crustacea: decapoda: portunidae) da zona de arrebentação da praia de Jaguaribe e estuário do Rio Jaguaribe, Ilha de Itamaracá, Pernambuco, Brasil

Abstract

Crustaceans are important members of tropical benthic communities, serving as food for humans. This study aimed to analyze the biometry, abundance and frequency of the population of Portunid crustaceans from Jaguaribe beach and Jaguaribe river estuary in Itamaracá-PE. The collections were carried out at three points: 1) the surf zone, 2) the river mouth and 3) the estuary. The crabs analyzed in this study are bycatch fish collected by trawling. Soon after collected, the crabs were packed in plastic bags and sent to the Bentos Laboratory (LABENTOS) at UFRPE/UAST. Individuals were identified, sexed and quantified. The data obtained were entered into an electronic spreadsheet for analysis of abundance, frequency and diversity. A total of 190 specimens were identified, distributed in five species: Callinectes danae (Smith, 1869), Callinectes ornatus (Ordway, 1863), Callinectes marginatus (Ordway, 1863), Arenaeus cribrarius (Lamarck, 1818) and Charybdis hellerii (Milne Edwards, 1867). Regarding relative abundance, C.danae was considered a dominant species at all points, obtaining 54% at point 1, 66% at point 2 and 65% at point 3. Arenaeus cribrarius was considered abundant at point 1 with 35% and common at point 2 with 20%, it was not collected at point 3. Callinectes marginatus presented 28% at point 3, being considered common, at point 1 it was classified as occasional with 5%. C. ornatus showed abundance at points 1, 2 and 3 respectively with 5%, 9% and 7%, thus being classified as occasional. Charybdis hellerii was classified as occasional with 5%. In the frequency of occurrence, it was found that C. danae is a species considered euconstant with 82% of the collected sample. C. ornatus and C.marginatus, presented 45% each, thus being constant species. A. cribrarius presented 36% and is considered an accessory species. Considered accidental, C.hellerii with only 18% of the total sample. For diversity the values were low for the river mouth (point 2) and for the interior of the estuary (point 3), and low for the surf zone (point 1). The evenness values were equitable, J'= 0.7276 for the surf zone (point 1), J'= 0.691 for the river mouth (point 2) and J'=0.7555 for the interior of the estuary (point 3). Ancova analysis demonstrated a positive growth relationship between carapace width, carapace length, abdomen width, and weight. Differing only for Callinectes danae in relation to carapace width and abdomen width. The low abundance of Charybdis helleri shows that the species is not endangering native crabs in this locality. This study contributed to increase the knowledge about the crabs on the island of Itamaracá