Seasonal variation in the water quality and chlorophyll a of semi-intensive shrimp ponds in a subtropical environment

摘要: Twelve water quality variables were measured at different intervals (biweekly and twice a week) in two ponds during consecutive production cycles semi-intensive shrimp farm on the Northwest coast of Mexico. The average harvest dry season (March–July, 95 days period) was 1822 kg ha-1, with an size 16.0 g; while rainy (August–January, 165-day 2125 11.9 g. In season, dissolved oxygen concentration tended to decrease as feeding rates phytoplankton biomass increasing until harvest. During both culture cycles, mean values temperature, salinity ammonium not significantly from those inlet water, whereas pH levels higher than incoming water. Nitrogen nutrients, particulate organic matter did exhibit seasonal differences; better yield feed conversion obtained reflect fact that temperature chlorophyll season; total suspended solids lower season. grow out cycles. Therefore, differences productivity between cannot be explained by quality.