ECOLOGIA DE ARTEMIA SP. (BRANCHIOPODA: ARTEMIDAE) EM UMA SALINA ARTESANAL NO ESTADO DO RIO GRANDE DO NORTE. 1. CARACTERIZAÇÃO POPULACIONAL VESUS PARÂMETROS AMBIENTAIS

Abstract

Amidst the few representatives of primary consumers in hypersaline environments, the microcrustaceans of the genus Artemia are noteworthy for playing an extremely important role to aquaculture and salt production. A monthly sampling program was carried out from Oct. 1989 to Sept. 1990, in eight sequential ponds of an artisanal saltwork located in Grossos, Rio Grande do Norte (Northeast Brazil), in order to study the population structure and density fluctuations of these organisms. Measurements of some physico-chemical parameters (salinity, temperature, pH, dissolved oxygen, nitrite, nitrate, phosphate, sulphate) were made concomitantly to relate them to biological parameters (population density and chlorophyll-a concentration). Large population density fluctuations were observed in all ponds. The greatest abundance of organisms was observed in the intermediate ponds 2, 3, 4, 5 and 6, with mean salinities between 99 and196%o. Food availability was the factor that most contributed to the distribution pattern of Artemia along the saltwork circuit. The sex-ratio was approximately 2 males for each female. The Artemia population was represented mainly by larval stages (nauplii and youngs), which contributed with 83.1 to 98.4% of the total number of individuals.

Keywords: Artemia sp., ecology, hypersaline environments, artisanal saltwork. NortheastBrazil.

Descritores: Artemia sp., ecologia, ambientes hipersalinos, salina artesanal, Nordeste doBrasil.