POPULATION STRUCTURE AND DYNAMICS OF THE FRESHWATER SHRIMP ATYAEPHYRA DESMARESTII (MILLET, 1831) IN THE LOWER RIVER MINHO (NW PORTUGAL)

摘要

This paper reports population dynamics, growth, and reproductive features of Atyaephyra desmarestii (Millet, 1831) from the estuary of the River Minho. Also, data were compared to information available from its distribution range. Samples were taken monthly between October 2010 and September 2011. Males were less abundant and smaller than females. The growth pattern showed hardly any increase during the autumn and winter, but a fast increase in size was recorded in spring, followed by slower growth in summer. The life span was 11-12 months. The reproductive period was from April to August, and mean fecundity reached 643 +/- 254 eggs/female. Juveniles started to appear in July and a strong recruitment occurred in summer and autumn. The ecological relevance of the shrimp supports the need of obtaining further and more specific knowledge on the relationship between geographical distribution and water quality. Our results coupled with longer time series in different localities will be essential to the conservation of the species.