TY - JOUR
T1 - Little Sharks in a Big World
T2 - Mitochondrial DNA Reveals Small-scale Population Structure in the California Horn Shark (Heterodontus francisci)
AU - Canfield, Sean J.
AU - Galván-Magaña, Felipe
AU - Bowen, Brian W.
N1 - Publisher Copyright:
© 2022 The Author(s). Published by Oxford University Press on behalf of The American Genetic Association. All rights reserved.
PY - 2022/5/1
Y1 - 2022/5/1
N2 - The California horn shark (Heterodontus francisci) is a small demersal species distributed from southern California and the Channel Islands to Baja California and the Gulf of California. These nocturnal reef predators maintain small home-ranges as adults and lay auger-shaped egg cases that become wedged into the substrate. While population trends are not well documented, this species is subject to fishing pressure through portions of its range and has been identified as vulnerable to overexploitation. Here, we present a survey of 318 specimens from across the range, using mtDNA control region sequences to provide the first genetic assessment of H. francisci. Overall population structure (φST = 0.266, P < 0.001) is consistent with limited dispersal as indicated by life history, with two distinct features. Population structure along the continuous coastline is low, with no discernable breaks from Santa Barbara, CA to Bahia Tortugas (Baja California Sur, Mexico); however, there is a notable partition at Punta Eugenia (BCS), a well-known biogeographic break between tropical and subtropical marine faunas. In contrast, population structure is much higher (max φST = 0.601, P < 0.05) between the coast and adjacent Channel Islands, a minimum distance of 19 km, indicating that horn sharks rarely disperse across deep habitat and open water. Population structure in most elasmobranchs is measured on a scale of hundreds to thousands of kilometers, but the California Horn Shark has population partitions on an unprecedented small scale, indicating a need for localized management strategies which ensure adequate protection of distinct stocks.
AB - The California horn shark (Heterodontus francisci) is a small demersal species distributed from southern California and the Channel Islands to Baja California and the Gulf of California. These nocturnal reef predators maintain small home-ranges as adults and lay auger-shaped egg cases that become wedged into the substrate. While population trends are not well documented, this species is subject to fishing pressure through portions of its range and has been identified as vulnerable to overexploitation. Here, we present a survey of 318 specimens from across the range, using mtDNA control region sequences to provide the first genetic assessment of H. francisci. Overall population structure (φST = 0.266, P < 0.001) is consistent with limited dispersal as indicated by life history, with two distinct features. Population structure along the continuous coastline is low, with no discernable breaks from Santa Barbara, CA to Bahia Tortugas (Baja California Sur, Mexico); however, there is a notable partition at Punta Eugenia (BCS), a well-known biogeographic break between tropical and subtropical marine faunas. In contrast, population structure is much higher (max φST = 0.601, P < 0.05) between the coast and adjacent Channel Islands, a minimum distance of 19 km, indicating that horn sharks rarely disperse across deep habitat and open water. Population structure in most elasmobranchs is measured on a scale of hundreds to thousands of kilometers, but the California Horn Shark has population partitions on an unprecedented small scale, indicating a need for localized management strategies which ensure adequate protection of distinct stocks.
KW - Baja California
KW - Channel Islands
KW - Gulf of California
KW - elasmobranch
KW - mtDNA
KW - phylogeography
UR - http://www.scopus.com/inward/record.url?scp=85134426382&partnerID=8YFLogxK
U2 - 10.1093/jhered/esac008
DO - 10.1093/jhered/esac008
M3 - Artículo
C2 - 35438775
AN - SCOPUS:85134426382
SN - 0022-1503
VL - 113
SP - 298
EP - 310
JO - Journal of Heredity
JF - Journal of Heredity
IS - 3
ER -