Effects of environmental conditions on the size-at-maturity of blue spiny lobster females of Panulirus inflatus (Decapoda: Palinuridae) at the southern coast of Sinaloa, Mexico

An artisanal fleet has operated a small-scale spiny lobster fishery targeting Panulirus gracilis and P. inflatus since the 1980s south of Sinaloa, within the Gulf of California, Mexico. This study analyzed how environmental conditions affected female maturation and size-at-maturity in blue spiny lobster (P. inflatus) females from southern Sinaloa. We sampled the wild population in 1997 (El Niño), 2008 (La Niña), and 2013 (neutral conditions). For each specimen, we recorded carapace length (CL), total weight, sex, and maturity; for each environmental condition, we fitted a logistic model to size-at-maturity data. We compared the resulting curves using a coincident curves test. A total of 2,230 lobster females of P. inflatus were analyzed, with CLs ranging from 35.2 to 107.5 mm. The size structure differed significantly among environmental conditions; under El Niño conditions, we observed the highest proportion of mature females and the smallest CL at female maturity. We detected significant differences between the coincident curves for El Niño and those for La Niña and neutral conditions. These results suggest that blue spiny lobster females (P. inflatus) exhibit environmentally driven variability in maturation and size-at-maturity, reflecting prevailing habitat conditions, with important implications for fisheries management.