Abstract The ecological and ethnological aspects of the harvesting of the cockle, Leukoma pectorina (Bivalvia: Veneridae), were investigated on Algodoal-Maiandeua Island, on the Amazon coast of Brazil. Ethnobiological data were collected through informal conversations, semi-structured interviews, and observations of the harvesting and processing of bivalves on the island. Following the ethnobiology study, the cockle beds were surveyed to evaluate the density of L. pectorina, body size and the meat yield of the cockles in the months of dry and rainy seasons. In the study area, cockling is a manual and artisanal activity, and L. pectorina is typically harvested by mothers with little formal education. The cocklers make their own tools, cockles are prepared in the family environment, and the majority of the catch is sold to commercial establishments on the island. Cockling is a sporadic activity used to complement the family income, and is more common during the dry season, when tourism increases on Algodoal-Maiandeua Island. The cockles are also larger and population density is higher during this season, and the cocklers themselves recognize this period as providing the most productive harvest. These findings reinforce the value of traditional knowledge for both scientific research and the planning of the management of coastal fishery resources.

Este trabalho avalia a variabilidade espaço-temporal da meiofauna do médiolitoral na praia de Ajuruteua, Estado do Pará. As coletas foram realizadas a cada dois meses, entre abril de 2003 a fevereiro de 2004 durante as marés de sizígia, em diferentes zonas da praia. As amostras foram retiradas com um amostrador cilíndrico de 3,14 cm² e fixadas em formalina salina a 5%. Em laboratório, as amostras foram passadas em malha de 0,063 mm de abertura e os organismos retidos identificados em nível de grandes grupos taxonômicos, contados e fixados em álcool etílico a 70%. A meiofauna esteve representada por oito grupos: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, adultos de Copepoda Harpacticoida e juvenis de Copepoda Harpacticoida. Nematoda foi o grupo dominante, representando 74% do total de indivíduos, seguido de Copepoda (19%). Pôde-se observar clara zonação horizontal da fauna, que se distribuiu em três faixas paralelas à linha de praia, com características significativamente distintas quanto à abundância, riqueza e densidade dos principais grupos taxonômicos. No médiolitoral médio foram observados valores significativamente mais elevados de riqueza e abundância, enquanto os valores mais baixos foram registrados no médiolitoral superior e inferior. A comunidade de meiofauna, ainda que não tenha variado significativamente entre períodos climáticos, foi mais rica e abundante nos meses secos. Os principais fatores responsáveis pelas variações espaço-temporais da meiofauna foram a ação das ondas e das marés e as variações na salinidade da água.

The present study investigates the spatio-temporal changes in the meiofauna community along the intertidal zone of Ajuruteua Beach, State of Pará, Brazil. Samples were collected during spring tides at different levels of the beach face every two months from April 2003 to February 2004. The material was sampled using a cylindrical corer (3.14 cm²) and fixed with 5% saline formalin. In the laboratory, samples were sieved through a 0.063 mm mesh screen and the retained organisms were identified at higher taxonomic levels, counted and preserved in ethanol 70%. Meiofauna was composed of eight groups: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, Copepoda and nauplius (Copepoda). Nematoda was the dominant group, representing 74% of total organisms, followed by Copepoda (19%). A clear faunal zonation was observed on three lines parallel to the shoreline, which showed significant differences in abundance, richness and density of the main taxonomic groups. The mean density was lowest in April and highest in December. The highest densities and richness were recorded in the mid intertidal zone, while the lowest values were recorded in the upper and lower intertidal zones. Meiofauna community was most rich and abundant during the dry months, although differences were not significant between climatic periods. The main factors involved in the spatio-temporal variations of meiofauna were wave and tidal action and salinity fluctuations.