Are fishing practices affecting the viability of the callo de hacha’s reproductive population?
To understand if Seri fishers’ harvests might be selectively targeting one sex over the other and thus threatening the viability of the reproductive population, I asked fishers if they could distinguish males from females. Fishers’ responses suggested that they could not. To assess their assertion, I estimated the sex ratio of a random sample of the harvests, examined if there was a correlation between shell and abductor muscle size differences related to sexual dimorphism, and reviewed the literature to determine what the reproductive cycle of CDHs is like for the species in this region. The sex determination of adult individuals was done visually by observing the highly conspicuous gonads of each harvested specimen. In the CDHs, as in other gonochoristic (separate sex) bivalve species, mature female gonad tissue presents itself as bright orange, whereas that of males is usually white to ivory (Strathmann 1987). To assess if the CDHs were externally sexually dimorphic, shell and abduc
