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6027922 
Journal Article 
Effects of net cages on the vertical distribution of zooplankton in a semi-arid reservoir, northeastern Brazil/Interferencia de tanques-rede na distribuicao vertical do zooplancton num acude do semi-arido, nordeste do Brasil 
Crispim, MC; Freitas, G; De Melo Junior, HdN 
2012 
Acta Limnologica Brasiliensia
ISSN: 0102-6712
EISSN: 2179-975X 
24 
2 
140 
Carneiro reservoir is an aquatic environment used for net cage aquaculture activities located in the semi-arid region of northeastern Brazil. Vertical distribution was evaluated in order to determine the effects of organic enrichment induced by aquacultures on zooplankton movements. Three replicate samples were collected during midday and midnight at each of three depths along the water column at two sites. The collected individuals were preserved in a 4% formaldehyde solution saturated with sugar and, later, identified and counted on a Sedgwick-Rafter chamber under a microscope, considering a minimum of 100 individuals per subsample. The higher species' richness and density were observed at the N station by the net cages compared to the F station distant from the net cages. Vertical movements were more pronounced at sites distant from net cages, suggesting that the increased food availability reduced the need for the typical vertical movements during daytime at sites near the net cages. 
ASFA Aquaculture Abstracts; Ecology Abstracts; Water Resources Abstracts; Aqualine Abstracts; Environment Abstracts; ASFA 1: Biological Sciences & Living Resources; vertical distribution; fish net cages; semi arid region; zooplankton; Intensive culture; Water column; Density; Aquatic environment; Microscopes; Species richness; Reservoirs; Aquaculture; Species Diversity; Daytime; Reservoir; Formaldehyde; Food availability; Cage culture; Plankton surveys; Semiarid environments; Population density; D 04040:Ecosystem and Ecology Studies