GENETIC DIVERSITY AND REPRODUCTIVE SUCCESS OF YELLOWTAIL KINGFISH Seriola lalandi (VALENCIENNES, 1833) IN CAPTIVITY

Eduardo Martínez-Matus*, Wayne Knibb, Mauricio Moreno-Alva, Roberto Flores-Aguilar, Clara E. Galindo-Sánchez, Claudia Farfán, Miguel A. del Río-Portilla, Fabiola Lafarga-De la Cruz
 
Ensenada Center for Scientific Research and Higher Education (CICESE)
Carretera Ensenada-Tijuana No. 3918, Zona Playitas, CP. 22860.
Ensenada, Baja California, Mexico
edumar@cicese.edu.mx

The Yellowtail kingfish, Seriola lalandi, is a cosmopolitan marine species that supports a fishery and aquaculture industry worldwide. S. lalandi is considered a specie with a great aquaculture potential because its rapid growth rate, its easy adaptation to captivity and its great commercial value. Yellowtail kingfish aquaculture industry of Australia and New Zealand accounts for about the 99% of the total production (less than 5,000 tons/year); while other countries as Chile, Mexico and USA are more recently developing its commercial mariculture. But, even thought hatchery production of S. lalandi are rapidly growing, there are some concerns to be solve as low survival rate, high deformities rates and growth heterogeneity developed during larval and early juvenile stages that limit the production capacity and efficiency. In Mexico, the first S. lalandi hatcheries are based on wild broodstock and F1 progenies will be, in the future, their domesticate broodstock. However, currently the genetic status of wild and captive S. lalandi populations is unknown. The knowledge of the genetic structure of populations in hatcheries it is extremely important, because this information can be use to establish breeding programs to manage reproduction in captivity. Considering that inbreeding can produce negative effects, such as "bottlenecks" identified when fertility, spawning, hatching or growing rates decrease or mortality and deformities rates increase. The objective of this project is to assess the S. lalandi reproductive success in captivity through the parental contribution inferred by microsatellites molecular markers and analyse the genetic diversity of broodstock and larvae.

Samples were collected from the caudal fin of two wild broodstock groups (MX1: 17 & MX2: 39 fishes), one batch of F1 progeny produced in captivity from batch MX1 (F1-MX1) and another batch of larvae imported from USA. Nine microsatellites were amplified by PCR and genotyping was performed on an Applied Biosystem 3500 Genetic Analyser. Genotypes were scored using Genemarker software. Genetic parameters were calculated using FSTAT 2.9.3 and ARLEQUIN 3.5. While parental assignment was done using COLONY 2.0. Software. Preliminary results showed there are no significant differences in the genetic diversity among the populations studied. However, the inbreeding coefficient (Fis) showed significant differences between the USA and MX2 populations. On the other hand, the parental contribution of broodstock females and males to progeny was 50 and 100 % respectively, but not all of them contribute in the same ratio. Three of eight females accounts for the 95% while three of nine males accounts for the 61% of the progeny. The identification of the elite broodstock will contribute to the settlement of specific genetic lines by keeping or improving the genetic diversity of hatchery reared yellowtail kingfishes.