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The longnose skates (Zearaja chilensis and Dipturus trachyderma) are the main component of the elasmobranch fisheries in the south-east Pacific Ocean. Both species are considered to be a single stock by the fishery management in Chile however, little is known about the level of demographic connectivity within the fishery. In this study, we used a genetic variation (560 bp of the control region of the mitochondrial genome and ten microsatellite loci) to explore population connectivity at five locations along the Chilean coast. Analysis of Z. chilensis populations revealed significant genetic structure among off-shore locations (San Antonio, Valdivia), two locations in the Chiloé Interior Sea (Puerto Montt and Aysén) and Punta Arenas in southern Chile. For example, mtDNA haplotype diversity was similar across off-shore locations and Punta Arenas (h = 0.46–0.50), it was significantly different to those in the Chiloé Interior Sea (h = 0.08). These results raise concerns about the long-term survival of the species within the interior sea, as population resilience will rely almost exclusively on self-recruitment. In contrast, little evidence of genetic structure was found for D. trachyderma. Our results provide evidence for three management units for Z. chilensis, and we recommend that separate management arrangements are required for each of these units. However, there is no evidence to discriminate the extant population of Dipturus trachyderma as separate management units. The lack of genetic population subdivision for D. trachyderma appears to correspond with their higher dispersal ability and more offshore habitat preference. [ABSTRACT FROM AUTHOR]

The yellownose skateZearaja chilensisis endemic to South America. The species is the target of a valuable commercial fishery in Chile, but is highly susceptible to over-exploitation. The complete mitochondrial genome was described from 694,593 sequences obtained using Ion Torrent Next Generation Sequencing. The total length of the mitogenome was 16,909 bp, comprising 2 rRNAs, 13 protein-coding genes, 22 tRNAs and 2 non-coding regions. Comparison between the proposed mitogenome and one previously described from “raw fish fillets from a skate speciality restaurant in Seoul, Korea” resulted in 97.4% similarity, rather than approaching 100% similarity as might be expected. The 2.6% dissimilarity may indicate the presence of two separate stocks or two different species of, ostensibly,Z. chilensisin South America and highlights the need for caution when using genetic resources without a taxonomic reference or a voucher specimen. [ABSTRACT FROM AUTHOR]

The yellownose skate Zearaja chilensis is endemic to South America. The species is the target of a valuable commercial fishery in Chile, but is highly susceptible to over-exploitation. The complete mitochondrial genome was described from 694,593 sequences obtained using Ion Torrent Next Generation Sequencing. The total length of the mitogenome was 16,909 bp, comprising 2 rRNAs, 13 protein-coding genes, 22 tRNAs and 2 non-coding regions. Comparison between the proposed mitogenome and one previously described from "raw fish fillets from a skate speciality restaurant in Seoul, Korea" resulted in 97.4% similarity, rather than approaching 100% similarity as might be expected. The 2.6% dissimilarity may indicate the presence of two separate stocks or two different species of, ostensibly, Z. chilensis in South America and highlights the need for caution when using genetic resources without a taxonomic reference or a voucher specimen.