The fish assemblage of the Mondego estuary was studied from June 2003 to May 2004. Five areas with different environmental conditions were sampled monthly, using a 2 m beam trawl (5 mm mesh size at the cod end). To complement information, sampling was also performed, seasonally, using a 7 m otter trawl with a 10 mm mesh size. Thirty-two species were identified. Dicentrarchus labrax, Pomatoschistus microps, Pomatoschistus minutus, Solea solea, Platichthys flesus and Diplodus vulgaris were the most abundant species. Marine juvenile migrants had the highest number of species, thirteen, followed by estuarine residents with eight species. Marine species that use the estuary as nursery grounds were the most abundant in terms of density and biomass. In spring and summer, juveniles occur in the upper, oligohaline areas, but afterwards, in autumn and winter, they tend to disperse to the middle and lower areas, with higher marine influence. Comparing the results obtained in this study with those reported in the early 1990's, a marked decrease in species richness can be noticed, which is probably due to anthropogenic factors, namely an increase in depth of the main channel and intense euthrophication processes in the middle and upper areas.
Sampling fish community and abiotic characteristics of water was done in five stations each month, during 1988, 1991 and I 992.The structure of the community is organised in four components status: occasional marine, occasional freshwater; sedentary and migrant Calendar of presence of this last group is given. Three habitats: marine, brackish, and freshwater were characterised with discriminant function analysis. AFC and communities indexes gave results about the space temporal variability of ichthyofauna Interpretations about functioning ecosystem are given in relation with habitat characteristics and migrant status of population that represents the maximum abundance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.