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 commercial exploitation was banned, from April 2010 to July 2014, sampling trips in the Gulf of California were performed to determine the spatial distribution, age structure, growth, length-weight relationship, and sex ratio. 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 Bahía San Luis Gonzaga, and 2) Piedra Consag, off the coast of San Felipe, Baja California. Totoaba catches in Bahía de La Paz, Baja California Sur, and Mazatlán, 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 may be considered at least of population stability. Now, it is necessary to carry out new research to evaluate the present condition of the population.