Petrechos de pesca como resíduo praial em uma área de proteção ambiental na costa paraense

Abstract

Abandoned, Lost or otherwise Discarded Fishing Gear (ALDFG) during fishing activities represent a global problem. This equipment corresponds to at least 640,000 tons of waste that accumulates annually in the oceans and causes impacts on aquatic fauna such as entanglement, ingestion, injuries, ghost fishing and can also act as vectors of chemical substances. This is the first quantification of ALDFG on beaches in Northern Brazil. The study was carried out on beaches on Algodoal Island, which is an Environmental Protection Area (APA), with the aim of evaluating whether there is spatial and temporal variation in ALDFG on different beaches (Caixa d´água, Farol, Princesa and Cação), considering their different environmental characteristics, and check whether there is the occurrence of organisms associated with ALDFG. The ALDFG were collected in the rainy and dry seasons (2022), in quadrants of 100m² in 30 transects containing three points: high tide line, intermediate and low tide line. The density of ALDFG and an Environmental Impact Factor (FIA) were calculated, considering the type of ALDFG, its mass and the environment where it was found. In total, 459 ALDFG items were collected (248 in the dry season and 211 in the rainy season), totaling 13.14 kg, among which the main ones were fragments, electrical cables, ropes and fishing nets, with emphasis on the nylon type material and blue color. Overall, the beaches had an average density of 0.023 items/m² and 0.755 g/m² in the rainy season and 0.028 items/m² and 0.704 g/m² in the dry season, with a low environmental impact (FIA between 0-1). But points with high impacts were also observed (FIA = 10 and FIA = 9), in points with the presence of rocky outcrops and vegetation, respectively. On Caixa d'água beach there is the presence of juvenile mangroves in the intertidal environment and rocky outcrops, as well as, it is located close to the port for fishing vessels, therefore, it was the beach that presented the largest quantity of ALDFG (274 items), the highest mass (6.35 kg), the highest density (2.74 items/m² and 63.52 g/m²), and consequently the highest Environmental Impact Factor (FIA = 10). Furthermore, associated with the ALDFG, 1,543 organisms were recorded (1,380 in the rainy season and 163 in the dry season) belonging to the following groups, barnacles, bivalves, paguros, crabs, isopods, polychaetes, gastropods, anemones and sea fleas, the majority of which were found associated with ropes and polystyrene buoys. Fishing is a recognized source of ALDFG and the presence of these residues in an APA can cause several impacts to this ecosystem.