PRODUCTION PERFORMANCE OF Cherax quadricarinatus FAMILIES FROM A NUCLEUS WITH INCREASED GENETIC VARIABILITY IN MEXICO

Alejandra V. Villarreal-García*, Humberto Villarreal1, Pedro Cruz1, José Naranjo1, Mayra Vargas1, José Andrés Hernández1 & Graciela Mora1.
 
1 Biohelis®, Innovation and Technology Park. Centro de Investigaciones Biológicas del Noroeste S.C. La Paz, Baja California Sur, México.
alejandra-villarreal2010@hotmail.com Student of Engineering in Biotechnology at the Technological Institute of Sonora, Ciudad Obregón, Mexico.
 

Commercial culture of Cherax quadricarinatus in Mexico is considered an alternative to diversify aquaculture production. The species was introduced to Tamaulipas, Mexico in 1996, and batches of juveniles and breeders were distributed to different farms countrywide. Several semi-intensive culture systems are used for the production of the species in states such as Tamaulipas, Michoacán and Baja California Sur. However, present trends in aquaculture require better efficiency and more environmentally friendly intensive technologies. During 20 years of multidisciplinary research by CIBNOR, significant technological advances have been achieved. Technology transfers to farmers have allowed commercial production to increase from 2,500 kg/Ha in 9-month cycles, obtained in in Tamaulipas in 1996, to 3,500 kg/Ha in 6-month cycles, in 1998, in Guayaquil, Ecuador, using 5%/day water exchange. In 2006, yields in Baja California Sur, were 3,500 kg/ha in 6-month cycles, without water exchange, increasing after the implementation of an intensive photo-heterotrophic system, to 5,000 kg/Ha in 6-month cycles, by 2008. However, the common practice at most farms, of restocking breeding ponds directly from grow out ponds, has generated a growing concern about the potential reduction in harvest size, deterioration of physiological health and decline in reproductive performance, due to inbreeding over time. Thus, the development and characterization of a nucleus with a wide genetic pool has become a priority for the incipient industry.

The objective of this study was to determine the level of genetic variability and differentiation of three divergent populations of C. quadricarinatus, and to evaluate the performance of families from parental and reciprocal crossings of these groups. We sourced and quarantined RedClaw from commercial farms in Tamaulipas, Michoacán and Baja California Sur, before selection for DNA extraction and rPCR amplification. Twenty specific microsatellites were used to determine allelic frequency. By pairing one male and one female, we established 80 families in 1,500 l tanks, with water at constant temperature (26+2oC) and continuous aeration. Breeders were fed daily at 5 pm with a 35% CP pelleted feed. When eggs were identified in the female pleopods, the male was removed. After juvenile release, the females were removed to avoid cannibalism. After 45 days, the young from each family were weighed, counted, and cultivated in the 1,500 l tanks for 120 days. Final mean weight and survival were determined and a regression model for weight increase for each family was obtained. Results and the implications of the genetic selection program for the consolidation of the industry in Mexico are discussed.