LIFE-HISTORY AND CONSERVATION OF TOTOABA-MACDONALDI

We conducted a literature review on the biology, ecology, fishery, and protection of totoaba (Totoaba macdonaldi), an endemic, threatened fish of the Gulf of California, Mexico. Reinterpretation and integration of published and unpublished information enabled us to confirm and estimate specific biological parameters of the totoaba, make hypothetical constructs of its life history, and to propose ideas for its preservation. In specific, we found (1) that the mean age of first reproduction of male and female totoaba are 6 and 7 years, respectively; (2) that the intrinsic rate of natural mortality was estimated as 0.268 per year and (3) that. in the mid 1980s an estimated 120,300 juveniles died each year in the shrimp fishery by-catch and 6200 adults (26 kg average weight) died due to poaching. The parameters of an individual growth model for juveniles and adults were also estimated. Decreased spring water input from the Colorado River into the Gulf of California may have caused a contraction of the spawning season and a reduction of the carrying capacity of juvenile totoaba. An increase in annual survival during recent years indicates recovery of the stock that might be related to protection of adults We argue that habitat restoration, which includes the elimination of growth and recruitment over-fishing, is critical to increasing numbers of totoaba, and thereby lifting the fishing ban, and to the delisting of totoaba.