Estimation of the size at sexual maturity of the bat ray (Myliobatis californica) in northwestern Mexico through a multi-model inference

•Bat ray females have a larger median size at maturity than males.•Logistic models are redundant and estimate the same median size at maturity.•Gompertz’s model is useful for estimating median size at maturity.•The multi-model inference must be used to estimate median size at maturity.•The northwest coast of Baja California Sur could be a nursery area for bat ray. The median disc width at maturity DW^50) of males (n=91, 32.2–92.0 cm) and females (n=157, 31.0–130.0 cm) of the bat ray (Myliobatis californica) was estimated through a multi-model inference in northwestern Mexico. Gompertz’s model and four common logistics models (Lysack, Bakhayokho, White, and Brouwer and Griffiths) were compared and all fit the data well (Akaike’s differences ≤2). Logistics models estimated the same DW^50 for M. californica, and had similar Akaike’s weight suggesting that they are redundant models. Therefore, multi-model inference was performed individually with Gompertz’s model and each one of the logistic models to estimate an average model DW¯50, resulting in 64.6 cm DW for males and 99.0 cm DW for females in all analyzes. Multi-model inference is a useful tool to estimate the DW^50 of a species with greater reliability, but redundant models must not be combined in this analysis. Thus, in this case it is advisable to perform the multi-model inference with Gompertz’s model and any of logistic models. The information obtained could contribute to the fishing management of the species, which becomes more relevant considering the high percentage of immature individuals of M. californica (53% of males and 90% of females) observed in the landings from Bahía Tortugas zone, Mexico.