We conducted a literature review on the biology, ecology, fishery, and protection of totoaba (Totoaba macdonaldi), an endemic, threatened fish of the Gulf of Calfornia, Mexico. Reinterpretation and integration of published and unpublished information enabled us to confirm and estimate specific biological parameters of the totooba, make hypothetical constructs of its life history, and to propose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.

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Para evaluar algunos aspectos demográficos de Totoaba macdonaldi 40 años después de que se prohibió su explotación comercial, se realizaron muestreos en el Golfo de California de abril de 2010 a julio de 2014. Se determinó la distribución espacial, la estructura de edad, el crecimiento, la relación longitud-peso y la proporción de sexos. Con base en la detección de anillos de crecimiento en otolitos, la edad de los peces comprendió de 0 a 19 años. Se identificaron dos áreas de reclutamiento; 1) Islas Las Encantadas, cerca de Bahía San Luis Gonzaga, y 2) Piedra Consag, frente a la costa de San Felipe, Baja California. Las capturas de totoaba en Bahía de La Paz, Baja California Sur y Mazatlán, Sinaloa, sugieren un nuevo registro que amplía su rango histórico. Sobre la base de un enfoque bayesiano, se estimaron los parámetros de crecimiento de von Bertalanffy para la población en su conjunto, y separados por sexo (hembra y macho) con tasas de 0.27, 0.28 y 0.31 año-1, respectivamente. La relación longitud-peso obtenida sugiere un crecimiento isométrico. La proporción de sexos no mostró diferencias significativas (p > 0.05) con respecto a la relación esperada 1:1. La expansión del rango de distribución y la estructura de edad observada hasta el año 2013-2014 puede considerarse al menos de estabilidad de la población. Ahora, es necesario llevar a cabo nuevas investigaciones para evaluar el estado actual de la población.

Background The fish Totoaba macdonaldi is endemic to the Upper Gulf of California. Its migratory movements involve sites with high levels of trace elements in the environment that can accumulate in tissues. In this study, lead (Pb), copper (Cu), cadmium (Cd), zinc (Zn) and iron (Fe) concentrations in male and female totoaba liver and muscle were quantified at various sexual maturity stages along the species’ geographic distribution. Methods Generalized linear models were used to explore associations between trace element concentrations and season of the year, sex/maturity stage, and total fish length. Results No detectable Pb concentrations were recorded in liver or muscle; Cu, Cd, Zn and Fe contents in totoaba liver and muscle were typical of fish inhabiting areas with no contamination issues and are within international maximum permissible levels for human consumption. Variations in the content of Cd, Cu, Zn and Fe in liver of totoaba seem to be more related to the feeding and reproductive physiology of this species than as result of environmental exposure. Results suggest that consumption of totoaba muscle does not pose a public health risk. Furthermore, depending on the sex/maturity stage of totoaba, this fish’s muscle may provide approximately 70% Cu, 60% Zn and 100% Fe of the recommended dietary reference intake.