Selection of a New Nile Tilapia Genetic Line to Provide Broodstock for Southeastern
Mexico
Tenth Work Plan, Reproduction Control Research 2 (10RCR2)
Final Report
Mario Fern‡ndez-Perez
Divisi—n AcadŽmica de Ciencias Agropecuarias
Universidad Ju‡rez Aut—noma de Tabasco
Villahermosa, Tabasco, Mexico
Wilfrido M. Contreras-S‡nchez
Laboratorio de Acuacultura
Universidad Ju‡rez Aut—noma de Tabasco
Villahermosa, Tabasco, Mexico
Grant W. Feist and Guillermo Giannico
3Department of Fisheries and Wildlife
Oregon State University
Corvallis, Oregon, USA
Carl B. Schreck
Oregon Cooperative Fishery Research Unit
Biological Resources DivisionÑUS Geological Survey
Department of Fisheries and Wildlife
Oregon State University
Corvallis, Oregon, USA.
Undergraduate Research Student: Isidro L—pez-Ramos
Abstract
Since 1964, Mexico has imported five species of tilapia for aquaculture purposes. Despite the establishment and long use of tilapia culture as a major economic activity and as a high-quality source of food, the emergence of this activity from a technical standpoint has been minimal. Some of the most important factors for the development of tilapia culture in Mexico are access to genetically improved species for better growth, characterization of species and lines present in Mexico, and the development of dependable methods for the production of monosex populations of males. The use of improved tilapia with high mass production has contributed to increasing its popularity among producers. We initiated a selective breeding program using 220 females and 110 males selected from a batch of fish purchased from Egypt by the State government. This first batch was selected using discriminant analysis for fish that best resembled Nile tilapia. The analysis was based on length, weight, number of scales, fins, head length, mouth diameter, and eye diameter. These fish were stocked in 200 m2 ponds for grow-out. From the fry obtained, three selections were made: one at 60 days, a second at 120 days (at this point the fish were separated by sex), and a third at 11 months. Six hundred females and 400 males were selected based on a combination of the best length and condition factor to obtain an F1 generation. These fish were stocked in 200 m2 ponds and allowed to breed. From the fry obtained, 60% of the total were selected for grow-out and a second round of selection was performed to obtain the F2 generation. Progeny obtained from the F2 broodstock were compared to both fry produced from a wild stock from the San Pedro River and from the San Pedro State hatchery. In general the selected Egypt line had better reproductive performance and good survival and growth. This study was conducted as a collaborative effort between Universidad Ju‡rez Aut—noma de Tabasco, the National Council for Science and Technology, and the Office for Agriculture and Fisheries Development in Tabasco, Mexico. This combined effort has allowed us to work at the Jose Narciso Rovirosa hatchery (using 200, 1,000, and 2,000 m2 ponds) and to use fish first selected by Mario Fern‡ndez-Perez in 2000.
