Population Genetic Analysis for Stock Enhancement of Silver Sea Bream (Rhabdosargus sarba) in Taiwan

Abstract

Stock enhancement is a method for replenishing depleted wild finfish populations by supplementing them with hatchery-raised fish. In Taiwan, silver sea bream (Rhabdosargus sarba) is a predominant commercial species involved in stock enhancement projects. Although management agencies conduct stock enhancement projects, there are a lot of private releases without records. Stock enhancement is performed by the private aquaculture sector without accurate genetic records, potentially leading to unintended consequences for wild populations. We analyzed the genetics of 459 wild and 701 hatchery-reared specimens from nine batches produced by various hatcheries. Wild and hatchery-reared samples could be considered two separate clades by using a set of stable and informative microsatellite markers including type I (from gene introns and 3′UTR) and type II markers (randomly picked up from genome). Type I microsatellite markers could more sensitively reflect the loss of genetic diversity more than type II markers in the domestication process. All specimens were considered native by using mtDNA COI and microsatellites. The genetic composition of the wild population is relatively simple, and the estimated low contribution rate of the hatchery stock (1.3–10.9%; 6–50/459) indicated a weak but significant genetic effect of stock enhancement. Therefore, establishing standards for the stock enhancement of silver sea bream for more effective supplementation of wild populations is imperative.

Phylogeographic Structure of Freshwater Tor sp. in River Basins of Sabah, Malaysia

“…The current study showed Tor populations appear to be significantly structured into geographically discrete subpopulations across drainages. Given that all clades are historically isolated, monophyletic, and having a high level of genetic differentiation [79], fulfilling the criteria of an ESU [5,97,98]; thus, this study suggests that all clades were treated as an ESU. Because of insignificant genetic differentiation values, River Bongawan and River Kimanis, as well as River Moyog and River Tuaran, can be combined as a unit.…”

Development of EST-Molecular Markers from RNA Sequencing for Genetic Management and Identification of Growth Traits in Potato Grouper (Epinephelus tukula)

“…Genetic diversity was high in every generation and breed in which we used molecular markers to trace, manage, and prevent inbreeding and intra- and interspecies interbreeding [ 108 , 109 , 110 ]. We discovered that functional (type I) and nonfunctional (type II) SSR markers have low genetic diversity in breeding selection, with functional SSR markers derived from candidate stocks and juveniles being more sensitive than nonfunctional SSR markers [ 111 ]. However, an organism cannot select the best genotype–phenotype combination, probably because various genotypes may be lost during artificial selection with functional molecular markers [ 112 , 113 ].…”

Utilizing ISSRseq genotyping to assist growth selection in tomato grouper (Cephalopholis sonnerati) without broodstock information

“…Molecular markers are DNA segments associated with specific genes or traits, enabling researchers to identify and select individuals with desirable characteristics and differentiate between various families, populations, and species (Hsu et al, 2011; Hsu & Gwo, 2017; Hsu, Huang, Lee, et al, 2020; Hsu, Huang, Lin, et al, 2020). They are now widely used in fisheries and aquaculture research (Hsu et al, 2022; Wong et al, 2022; You et al, 2020).…”