Observations on the Reproductive Biology of the Chihuil Sea Catfish in the Southeast Gulf of California: Implications for Management
Victor Muro and Felipe Amezcua
Abstract.—The chihuil sea catfish Bagre panamensis from the southeastern Gulf of California is an important species that is commercially exploited. Currently, the species is thought to have relatively high abundances. However, studies on biology of this species are scarce; therefore, harvest regulations do not exist for this species in Mexico. The aim of this work was to describe reproductive biology of this species as an initial basis for management of this resource, to assess if the current fishing practices could have an effect on its population, and finally, to begin promoting effective management of this population. Gill-net samples were carried out from October 2008 to October 2009. All fish were dissected; gender and gonad maturity stage were determined macroscopically. Results indicated that the spawning season runs from May to August and generally with synchronic gonad development. Fecundity of the chihuil sea catfish was 36, which is low because this species shows parental care via oral incubation of fry, reducing mortality. Estimated length at first maturity is 350 mm total length (TL). Average length at first catch from the artisanal gill-net fishery is 300 mm TL, indicating that this fishery is harvesting fish that have yet to have had a single reproductive event. A large number of captured fish consisted of males that were incubating fry, thus, likely causing large fry mortality. Current harvest practices may have a negative effect on the chihuil sea catfish population in the Gulf of California. A closed season is proposed for this species from May to August with a minimum harvest length of 400 mm TL.