Macrofauna em ambientes recifais de praias urbanas do Recife - PE, Brasil

Abstract

The beaches of Pina and Boa Viagem, Recife-PE, are urban beaches and present in addition to ecological importance, socioeconomic importance. In order to characterize the macrofauna of the aforementioned beaches, aiming to provide recent data on the quali-quantitative composition of the same, monthly collections were carried out, always at low tides daytime syzygy, from May to July (rainy season), and September to November (dry season) 2018 at Pina beach, and from January to March (dry season), and May to July (rainy season) 2019 at Boa Viagem beach. The macroalgae were collected with the aid of plastic bags and deposited in plastic containers containing water from the site, with three samples of macroalgae per month. Regarding the reef macrofauna, specimens were collected manually, with the aid of tweezers and deposited in plastic containers. In the laboratory, the macrofauna associated with macroalgae was identified at the level of large groups and accounted for. Mollusks obtained from macroalgae, as well as decapod crustaceans and molluscs collected on reefs, were identified at the species level with the help of specialized literature. Associated with macroalgae, 11 and 13 zoological taxa were removed for the beaches of Pina and Boa Viagem, respectively, with Copepoda being the dominant one on Pina beach, and Isopoda and Amphipoda Gammaroidea in the dry and rainy periods, respectively, on Boa Viagem beach. As for gastropods associated with macroalgae, 18 species were obtained at Praia do Pina, and 22 at Boa Viagem beach. Comparing the seasonal periods, on both beaches the dry period presented greater wealth than the rainy one. Eulithidium affine stood out for being the dominant species on Pina beach, as well as on Boa Viagem beach in the rainy season, with Mitrella ocellata being the dominant one in the dry season. Regarding the reef macrofauna, 10 species were obtained at Pina beach and 12 at Boa Viagem beach. Comparing the two seasonal periods, the rainy season was the one that showed the greatest wealth and abundance at Pina beach, while at Boa Viagem beach it was the dry period. In both beaches studied, Stramonita haemastoma and Pachygrapsus tranversus, were the species of mollusk and decapod crustacean respectively, which presented greater abundance. Regarding the frequency of occurrence, on the beach of Pina Stramonita haemastoma was the most frequent mollusk, while on the beach of Boa Viagem the species Brachidontes exustus, Fissurella clenchi and Stramonita haemastoma were the most frequent occurrence. Among decapod crustaceans, Pachygrapsus tranversus was the one with the highest frequency on the two beaches studied. Callinectes exasperatus and Callinectes ornatus would be a new occurrence record for Boa Viagem beach. The macrofauna obtained in the present study, showed less abundance of individuals and less value of wealth, when compared to previous works, which may be related to anthropic actions, such as increased trampling. Despite this, it is considered that the two beaches studied showed good biological diversity, since they are strongly impacted.