ESTUDIO DE LAS VARIACIONES AMBIENTALES EN EL CULTIVO DE PECES EN JAULAS FLOTANTES MARINAS EN SAN BLAS, NAYARIT

We studied the environmental variations that occurred in a culture of Lutjanidos in marine floating cages (10 cages) in the water column and the sediment, in San Blas Nayarit, Mexico. For this, floating cages with dimensions of 25m ^ 3 were used where they were measured in situ in 12 stations in three sets (Naranjo, Cultivo, Campana): temperature ° C), salinity (ups), pH and dissolved oxygen (00 mg / l ) in the water column at three different depths: Surface, Medium and Bottom during a year of cultivation. Also the quality of the water in the area of ​​influence was analyzed, for it was measured during that same year and in the same stations: ammonium not ionized (NH3), nitrites (NO2), nitrates (NO3), phosphorus (P), phosphates (PO4) in the three water depths mentioned above. Only significant differences were found with respect to depth in ammonium, nitrites (random blocks, p <0.01), the highest concentrations were recorded in the Fund (NH3 = 1.06 ± 1.03 mg / l) (N02 = 0.16 ± 0.15 mg / l) and in OD the maximum concentrations were recorded on the surface (5.85 ± 0.9 mg / l). With respect to the different groups of stations, only significant differences were found in the phosphates, for which a completely random design was applied where p <0.01 (Bell 0.32 ± 0.21 mg / l), all other variables were found within the optimal ranges. The concentrations of nitrogen, particulate organic matter and phosphorus of the sediment were analyzed in seven stations (North, South, East, West, A, B, C), a completely randomized design was applied (p <0.01), only differences were found significant in the phosphorus of the North station (3.95 ± 0.55%). The data of the environmental variables (surface temperature, chlorophyll-a, organic matter) were obtained from the GIOVANNI-NASA database with quarterly time series, with a maximum range of 4 km resolution. It is concluded that the culture of fish in floating cages in the study area does not cause significant negative effects to the environment.