Empirical equations for estimating the size at sexual maturity in shrimps, lobsters, and crabs

Size at sexual maturity is a key population parameter, particularly in commercially important species. The traditional estimation methods require identifying mature individuals by physiological and/or morphometric sexual characters. In this study, we propose using linear regression model based on the relationship between the size at sexual maturity and maximum sizes of shrimps, lobsters, and crabs, as an alternative when traditional methods cannot be applied. Data of size at sexual maturity and maximum size were obtained from the scientific literature and ln-transformed. A total of 275 papers were reviewed covering 64 shrimp, 20 lobster, and 88 crab species. Linear regression analysis revealed a close to 1 positive slope and negative intercept values, with determination coefficient generally exceeding 0.80. Differences between reported values and our estimates were typically within 20%, though larger deviations occurred when maturity ratios fell outside 0.45–0.75 range. The proposed linear regression parameters offer a reliable alternative for estimating sexual maturity size when traditional methods are not feasible.