title: Identification of naturally occurring hybrids between two overexploited sciaenid species along the South African coast.
abstract: Hybridisation between fish species can play a significant role in evolutionary processes and can influence management and conservation planning, however, this phenomenon has been widely understudied, especially in marine organisms. The distribution limits of two sciaenid species (silver kob, Argyrosomus inodorus, and dusky kob, A. japonicus) partly overlap along the South African coast, where both species have undergone severe depletion due to overfishing. Following the identification of a number of possible cases of species misidentification or hybridisation (21 out of 422 individuals), nuclear and mitochondrial DNA data (12microsatellite loci and 562bp of the COI gene) were analysed to investigate the genetic composition of these individuals. Results indicated a field-based species misidentification rate of approximately 2.8% and a rate of natural hybridisation of 0.7%. Interestingly, all hybrid fish resulted from first-generation (F1) hybridisation events, which occurred exclusively between silver kob females and dusky kob males. Whether hybridisation is the result of natural events (such as secondary contact following a shift in distribution range), or anthropogenic activities (size-selective pressure due to overfishing), these findings have important implications for critical recovery and future management of these species in the wild.
authors.affiliation: Department of Genetics, Stellenbosch University, van der Bijl Street, JC Smuts Building, Stellenbosch 7600, South Africa. Electronic address: lmirimin@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Mirimin
authors.affiliation: Department of Agriculture, Forestry and Fisheries, Private Bag X2, Roggebaai, 8012 Cape Town, South Africa; Department of Animal Sciences, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
authors.forename: S E
authors.initials: SE
authors.lastname: Kerwath
authors.affiliation: Department of Agriculture, Forestry and Fisheries, Private Bag X2, Roggebaai, 8012 Cape Town, South Africa.
authors.forename: B M
authors.initials: BM
authors.lastname: Macey
authors.affiliation: Department of Genetics, Stellenbosch University, van der Bijl Street, JC Smuts Building, Stellenbosch 7600, South Africa.
authors.forename: A E
authors.initials: AE
authors.lastname: Bester-van der Merwe
authors.affiliation: Department of Agriculture, Forestry and Fisheries, Private Bag X2, Roggebaai, 8012 Cape Town, South Africa; South African Institute of Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa.
authors.forename: S J
authors.initials: SJ
authors.lastname: Lamberth
authors.affiliation: Department of Genetics, University of Pretoria, Agricultural Sciences Building, Hatfield, Pretoria 0083, South Africa.
authors.forename: P
authors.initials: P
authors.lastname: Bloomer
authors.affiliation: Department of Genetics, Stellenbosch University, van der Bijl Street, JC Smuts Building, Stellenbosch 7600, South Africa.
authors.forename: R
authors.initials: R
authors.lastname: Roodt-Wilding
mesh_terms: D000818:Animals; D017756:Aquaculture; D002467:Cell Nucleus / Q000235:genetics; D003247:Conservation of Natural Resources; D004272:DNA, Mitochondrial / Q000235:genetics; D005260:Female; D006824:Hybridization, Genetic; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D010473:Perciformes / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D013019:South Africa
chemical_list: D004272:DNA, Mitochondrial
keywords: Argyrosomus; Hybridisation; Microsatellites; Overfishing; mtDNA COI