Benavides M.T., Horn R.L., Feldheim K.A., Shivji M.S., Clarke S.C., Wintner S., Natanson L., Braccini M., Boomer J.J., Gulak S.J.B., Chapman D.D.
Institute for Ocean Conservation Science, School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY 11794, United States; Guy Harvey Research Institute, Save Our Seas Shark Center, Nova Southeastern University Oceanographic Center, Dania Beach, FL 33004, United States; Field Museum, Pritzker Laboratory for Molecular Systematics and Evolution, 1400 South Lake Shore Drive, Chicago, IL 60605, United States; Oceanic Fisheries Programme, Secretariat of the Pacific Community, BPD5 CEDEX, Noumea 98848, New Caledonia; KwaZulu-Natal Sharks Board, University of KwaZulu-Natal, Umhlanga Rocks 4320 and Biomedical Resource Unit, Private Bag 2, Durban 4000, South Africa; NOAA Fisheries Service, 28 Tarzwell Dr., Narragansett, RI 02882, United States; Fisheries Centre, The University of British Columbia, Vancouver, BC V6T1Z4, Canada; Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia; NOAA Fisheries Service, Southeast Fisheries Science Center, 3500 Delwood Beach Road, Panama City, FL 32408, United States
Benavides, M.T., Institute for Ocean Conservation Science, School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY 11794, United States; Horn, R.L., Guy Harvey Research Institute, Save Our Seas Shark Center, Nova Southeastern University Oceanographic Center, Dania Beach, FL 33004, United States; Feldheim, K.A., Field Museum, Pritzker Laboratory for Molecular Systematics and Evolution, 1400 South Lake Shore Drive, Chicago, IL 60605, United States; Shivji, M.S., Guy Harvey Research Institute, Save Our Seas Shark Center, Nova Southeastern University Oceanographic Center, Dania Beach, FL 33004, United States; Clarke, S.C., Oceanic Fisheries Programme, Secretariat of the Pacific Community, BPD5 CEDEX, Noumea 98848, New Caledonia; Wintner, S., KwaZulu-Natal Sharks Board, University of KwaZulu-Natal, Umhlanga Rocks 4320 and Biomedical Resource Unit, Private Bag 2, Durban 4000, South Africa; Natanson, L., NOAA Fisheries Service, 28 Tarzwell Dr., Narragansett, RI 02882, United States; Braccini, M., Fisheries Centre, The University of British Columbia, Vancouver, BC V6T1Z4, Canada; Boomer, J.J., Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia; Gulak, S.J.B., NOAA Fisheries Service, Southeast Fisheries Science Center, 3500 Delwood Beach Road, Panama City, FL 32408, United States; Chapman, D.D., Institute for Ocean Conservation Science, School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY 11794, United States
Genetic stock structure information is needed to delineate management units and monitor trade in sharks, many of which are heavily exploited and declining. The dusky shark Carcha -rhinus obscurus is a large apex predator that is sought after for its fins and is considered highly susceptible to overexploitation. The International Union for the Conservation of Nature (IUCN) classifies this species as 'Vulnerable' globally and 'Endangered' in the northwest Atlantic. We make the first assessment of global stock structure of C. obscurus by analyzing part of the mitochondrial control region (mtCR) in 255 individuals sampled from 8 geographically dispersed locations. We found 25 mtCR haplotypes and rejected a hypothesis of panmixia (analysis of molecular variance, ΦST = 0.55, p < 0.000001), detecting significant differentiation between 3 management units: US Atlantic (USATL), South Africa (SAF), and Australia (AUS). We also found preliminary evidence of population structure between the USATL and southwest Atlantic (Brazil). There were no shared haplotypes between the western Atlantic and Indo-Pacific. These analyses suggest that replenishment of the collapsed USATL management unit via immigration of females from elsewhere is unlikely. Mixed stock analysis (MSA) simulations show that reconstruction of the relative contributions of USATL, SAF, and AUS management units to the Asian fin trade is possible using these mtCR sequences. We suggest avenues for obtaining samples to conduct MSA of the shark fin trade, which could enhance management of dusky sharks and other species that are exploited for their fins. © Inter-Research 2011.
