A ecologia e pesca da população de mero Epinephelus itajara Lichtenstein, 1822, na plataforma continental amazônica.

Abstract

The species Epinephelus itajara is a large grouper belonging to the Serranidae family and inhabits the tropical and subtropical waters of the Atlantic Ocean. Fish of the Serranidae family are characterized by having robust bodies, large mouths, and are frequently found in coral or rocky environments. The species is a highly valued resource worldwide and, therefore, has been suffering from overfishing and habitat destruction. On the Amazon continental shelf, there is a lack of ecological studies and studies on the fishing dynamics of the species. The present work aims to analyze the fishing of the grouper on the Amazon continental shelf and how it is affected by the variability of meteorological and oceanographic variables. For this purpose, fishing landing data from the ESTATPESCA program were analyzed, where 2,474 landings were recorded between 1997 and 2007, in locations from 13 municipalities in the state of Pará. The results obtained demonstrate the existence of six types of vessels and 22 active fishing gear, with 50% of the vessels being small, mainly using bottom longlines and gillnets. With diversified fishing, diversity indices such as Shannon, Pielou, and Simpson were adapted. Another methodology applied was the creation of a fishing importance ranking to define which vessels and gear are most important for the capture of the species. From this ranking, the five combinations of vessels and gear that would be intrinsically analyzed were determined. Among the landing municipalities, Belém stands out as the one that would receive the most grouper landings, although in a smaller quantity (kg) than Bragança. A relative abundance index (CPUE) was estimated for the species based on the ratio between the catch and the available effort measures (days at sea, length or quantity of gear, and number of fishermen). The CPUE for fishing with longlines and gillnets was calculated, and it was found that the CPUE of the species with longlines showed a growth trend until the year of the prohibition of the species' capture, while gillnets tended to decrease. The landing time series had some continuity gaps due to the absence of landing records in some months. Therefore, the study used a methodology based on PCNM (Principal Coordinates of Neighbor Matrices) analysis, which estimated the missing data from the CPUE series. It was concluded that the capture of the grouper is multispecific, and at least five combinations of gear and vessel significantly land it. The landings of vessels using longlines are higher than those using gillnets, and their CPUE for longlines did not show a decline until 2003. The relationship between environmental variables and the relative abundance index showed a strong correlation with salinity and sea surface temperature in 4 the coastal areas of the states of Pará and Maranhão and in the retroflexion area of the North Brazil Current. These variables mainly influence the younger stages of the species and should determine the species' larval dispersion process.