New Features On Spatial Distribution, Age And Growth Of The Protected Species Totoaba Macdonaldi In The Gulf Of California

To assess some demographic aspects of Totoaba macdonaldi, 40 years after its commercial exploitation was banned, sampling trips in the Gulf of California were performed from April 2010 to July 2014. The spatial distribution, age structure, growth, length-weight relationship, and sex ratio were determined. Based on otolith growth ring detection, fish age comprised from 0 to 19 years. Two recruitment areas were identified; 1) Las Encantadas islands, close to Bahia San Luis Gonzaga, and 2) Piedra Consag, off the coast of San Felipe, Baja California. Totoaba catches in Bahia de La Paz, Baja California Sur, and Mazatlan, Sinaloa, suggest a new record that broadens its historical range. Based on a Bayesian approach, the von Bertalanffy growth parameters were estimated for the population as a whole, and separated by females and males with rates of 0.27, 0.28 and 0.31year(-1), respectively. The length-weight relationship obtained suggests isometric growth. The sex ratio showed no significant differences (p > 0.05) from the expected 1:1 ratio. The expansion of the distribution range and the age structure observed until the year 2013-2014 can be considered as, at least, population stability. Further research is needed to evaluate the present condition of the population.