Restricted connectivity and population genetic fragility in a globally endangered Hammerhead Shark

Author(s)

Pinhal, Danillo ^[1] ; Domingues, Rodrigo R. ^[2] ; Bruels, Christine C. ^{[3, 4]} ; Ferrette, Bruno L. S. ^[5] ; Gadig, Otto B. F. ^[6] ; Shivji, Mahmood S. ^{[3, 4]} ; Martins, Cesar ^[7]

Affiliation

^[1] Univ Estadual Paulista UNESP, Inst Biociencias, Dept Genet, Lab Genom & Evolucao Mol, Rua Prof Doutor Antonio Celso Wagner Zanin S-N, BR-18618689 Botucatu, SP - Brazil

^[2] Univ Fed Sao Paulo, UNIFESP, Inst Mar, Dept Ciencias Mar, Rua Carvalho de Mendonca 144, BR-11070100 Santos, SP - Brazil

^[3] Nova Southeastern Univ, Guy Harvey Res Inst, 8000 North Ocean Dr, Dania, FL 33004 - USA

^[4] Save Our Seas Shark Res Ctr, Dania, FL - USA

^[5] Univ Santa Cecilia UNISANTA, Lab Genet & Conservacao, Rua Cesario Mota 8, BR-11045907 Santos, SP - Brazil

^[6] Univ Estadual Paulista UNESP, Inst Biociencias, Lab Pesquisa Elasmobranquios, Campus Litoral Paulista, BR-11330900 Sao Vicente, SP - Brazil

^[7] Univ Estadual Paulista UNESP, Inst Biociencias, Dept Morfol, Lab Genom Integrat, BR-18618689 Botucatu, SP - Brazil

• Document type: Journal article
• Source: Reviews in Fish Biology and Fisheries; v. 30, n. 3 JUN 2020.
• Web of Science Citations: 1

Abstract

Vagile, large-bodied marine organisms frequently have wide range dispersion but also dependence on coastal habitats for part of their life history. These characteristics may induce complex population genetic structure patterns, with resulting implications for the management of exploited populations. The scalloped hammerhead, Sphyrna lewini, is a cosmopolitan, migratory shark in tropical and warm temperate waters, inhabiting coastal bays during parturition and juvenile development, and the open ocean as adults. Here, we investigated the genetic connectivity and diversity of S. lewini in the western Atlantic using large sample coverage (N = 308), and data from whole mitochondrial control region (mtCR) sequences and ten nuclear microsatellite markers We detected significant population genetic structure with both mtCR and microsatellites markers (mtCR: phi(ST) = 0.60; p < 0.001; microsatellites: D-est 0.0794, p = 0.001, F-ST = 0.046, p < 0.05), and isolation by distance (mtCR r = 0.363, p = 0.009; microsatellites markers r = 0.638, p = 0.007). Migration and gene flow patterns were asymmetric and female reproductive philopatry is postulated to explain population subdivisions. The notable population differentiation at microsatellites markers indicates low-levels of male-mediated gene flow in the western Atlantic. The overall effective population size was estimated as 299 (215-412 CI), and there was no evidence of strong or recent bottleneck effects. Findings of at least three management units, moderate genetic diversity, and low effective population size in the context of current overfishing calls for intensive management aimed at short and long-term conservation for this endangered species in the western Atlantic Ocean. (AU)

• FAPESP's process: 07/03065-5 - Genetic population structure of the scalloped hammerhead shark Sphyrna lewini (Elasmobranchii: Sphyrnidae), inferred from microsatellite markers
• Grantee: César Martins
• Support type: Regular Research Grants
• FAPESP's process: 07/03067-8 - Hammerhead shark Sphyrna lewini (Elasmobranchii: Sphyrnidae) genetic population structure using microsatellites molecular markers and mitochondrial DNA
• Grantee: Danillo Pinhal
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/02420-8 - High-Tech Conservation: Combining oceanography, transcriptome and genomics to assess population genetic connectivity and local adaptation of the highly migratory mako shark (Isurus oxyrinchus) in the Atlantic Ocean.
• Grantee: Rodrigo Rodrigues Domingues
• Support type: Scholarships in Brazil - Post-Doctorate