TWO NEW EQUATIONS TO EVALUATE ALLOMETRY IN THE BLUE SHRIMP PENAEUS STYLIROSTRIS STIMPSON, 1871 (DECAPODA, PENAEIDAE) IN A COASTAL LAGOON FROM THE GULF OF CALIFORNIA

In Mexico, shrimp catch is the main fishing activity, and the second important species is the blue shrimp, Penaeus stylirostris. Specimens of P. stylirostris collected in 2016-2018 from inland waters (bay) and offshore (littoral) in the Santa Maria la Reforma lagoon (SMLR) system were analysed. The sexes were separated, and then individuals were measured in total length (L, mm) and weighed (W, g). The data were transformed into a natural logarithm and were adjusted to seven candidate models with a multi-model approach (Linear, Quadratic, Cubic, Broken stick, Two segments, Three segments and Four segments: the last two proposed in this study as new equations). A total of 30 439 specimens were analysed. Statistical differences were found in L between areas (KS test, p<0.0001). Positive and negative allometry was observed according to biometric relationship and sex. The best model was selected with the lowest value of the Akaike information criterion, resulting in the choice of the Four segments model.

Automated summary

This study analyzed samples of blue shrimp collected from offshore and inland waters in Mexico, and found statistical differences in body length among different areas. Positive and negative allometry was observed based on biometric relationships and sex. The best model selected was the Four segments model.