Early assessment of gilthead sea bream (Sparus aurata) spawning dynamics by mini‐broodstocks. (8th July 2017)

• Record Type: Journal Article
• Authors: García‐Fernández, Carmen; Sánchez, José A; Blanco, Gloria
• Is Part Of: Aquaculture research. Volume 49:Number 1(2018)
• Page Start: 36
• Page End: 47
• Publication Date: 2017-07-08
• Subjects: effective size -- embryonated eggs -- microsatellite loci -- parentage -- Sparus aurata -- spawning dynamics; Aquaculture -- Periodicals; Fishery management -- Periodicals; 639.8
• DOI: 10.1111/are.13430
• Languages: English
• ISSNs: 1355-557X

Abstract

Abstract: The implementation of any sustainable breeding program requires a maximization of effective size (Ne) to maintain inbreeding rate at minimum levels. However, the control of Ne remains a major challenge for those species whose reproduction in captivity is based on a spawning strategy where there is no control over the established matings. The present study aims to assess the spawning dynamic of gilthead sea bream ( Sparus aurata ) at different dates from two mini‐broodstocks (4 ♀ and 4 ♂). Here we report the use of a simple protocol based on the genotyping of fertilized eggs from a reduced set of microsatellite loci which provides a quick evaluation of daily spawning in terms of family structuring (number of active breeders and number and family size). According to our results, the daily spawning dynamics is characterized by a fluctuation in the number of active breeders, reaching maximum values (until 100%) during peak production phase. However, the proportion of possible mating (families) in a single daily spawning never exceeded more than 81%. Unbalanced parental contributions were highly frequent, with extreme cases involving the assignment of 50%–90% of the offspring to a single family. Therefore, the use of mini‐broodstocks and the grouping of spawning harvested at different dates are proposed as strategies to minimize the inbreeding risk by providing a more optimal pattern of family structuring (increase in the number of families obtained and a more balanced parental contributions) that entails a more conservative Ne/N ratio.