Elasmobranch bycatch from the Pacific Sierra (Scomberomorus sierra) artisanal gillnet fishery in the Gulf of California, Mexico, was assessed due to the particular vulnerability of elasmobranch populations to overfishing. Elasmobranchs are particularly susceptible due to their K-selected life history strategies; in addition the regions fished by the S. sierra fishery (shallow, coastal areas) are also those favoured by elasmobranchs as nursery areas, therefore suggesting that elasmobranch bycatch may contain many immature individuals, further damaging elasmobranch populations. The nine species most prevalent in the catches were assessed in this study. Length at maturity was found by fitting a logistic regression model to the maturity data, species with greater lengths at maturity tended to have larger amounts of juveniles in their catches, as these species would take a greater amount of time to mature before leaving the nursery areas, thereby being susceptible to being caught as a juvenile for longer. Seven of the elasmobranch species assessed consisted of >50% of juveniles making up the catches, suggesting that the areas used by the S. sierra fisheries are also used as nursery areas by these species. Mitigation measures for the problem of juvenile elasmobranch bycatch would be to implement protected areas around nursery areas.
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