This work aimed to determine the optimum stocking density of Penaeus vannamei, cultured in a photo-heterotrophic intensive circular system inlined grow-out ponds with minimal water replacement. Five intensive density levels (100, 300, 500, 700 and 900 ind m-3) were considered. The water quality measured for the 98 days grow-out period was within the adequate range for P. vannamei. TAN, nitrate and total phosphorus water quality were significantly higher (P < 0.05) at the higher density. Growth rates and survival decreased as density increased after 300 org m-3. Based on the results of this study, it was found that shrimp grows adequately in high biomass density (99.21 kg tank-1) and density of 500 ind m-3 in an intensive photo-heterotrophic system with a maximum harvest weight of 10 g.

The main purpose of this study was to review the growth models used in fish culture and demonstrate the benefit of using the most appropriate growth model for aquaculture studies. For this reason, another part of this study was to use a dataset from spotted rose snapper (Lutjanus guttatus Steindachner, 1869) cultured in floating cages to determine what growth models were applicable to this species. A total of 558 weight‐at‐age data points from a commercial farm located near Nayarit, Mexico were used. The fish were cultured for 270 days in three cages of 125 m3 capacity. The initial density was 25 fish m−3, with an average weight of 2.07 ± 0.52 g. Four asymptotic models (von Bertalanffy growth model, a logistic model, the Gompertz growth model and the Ratkowsky modified model), three nonasymptotic models (exponential, power extended and persistence models) and three versions of the generalized Schnute model were selected as candidate models. The best model was selected based on the Akaike information criterion. The maximum log‐likelihood algorithm was used to parameterize the models considering a multiplicative error structure. The survival was 90%, and the average final weight was 429.84 ± 31.53 g. We concluded that the best model for describing the growth of spotted rose snapper farmed in marine floating cages was the Schnute model.

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ABSTRACT. Combined effects of temperature (25, 30 and 35°C) and salinity (15, 25, 35 and 45 g L -1 ), on the body composition and energetic value in the juvenile spotted rose snapper (Lutjanus guttatus), were investigated over 90 days. Significant effects of temperature, salinity, and their interaction on body composition and energetic value were analyzed. Low temperatures (25°C) significantly reduced the protein and increase lipid content in the body. In a temperature of 30°C, the highest energetic value was recorded, and in the highest salinity (45 g L -1), the energetic value was reduced. The salinity of 15 has the highest growth, protein content, and energetic value. It was found that the optimal temperature-salinity combination for the best relationship of growth (3.8% d . The effect of temperature was directly proportional to the increase in protein and inversely with the content of lipids in the body; salinity has its main effect negatively on these parameters in the highest salinity (45 g L -1 ).

In the present study, size-at-age data (length and weight) of marine cage-reared spotted rose snapper Lutjanus guttatus were analyzed under four different variance assumptions (observed, constant, depensatory, and compensatory variances) to analyze the robustness of selecting the right standard deviation structure to parametrize the von Bertalanffy, Logistic, and Gompertz models. The selection of the best model and variance criteria was obtained based on the Bayesian information criterion (BIC). According to the BIC results, the observed variance in the present study was the best way to parametrize the three abovementioned growth models, and the Gompertz model best represented the length and weight growth curves. Based on these results, using the observed error structure to calculate the growth parameters in multi-model inference analyses is recommended.