Meristic variation in beaked redfishes, Sebastes mentella and S . fasciatus , in the Northwest Atlantic

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Author: Ni, I-H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1982
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Newfoundland; Baffin Bay; Baffin Island; Greenland; Baffin; Northwest Atlantic; Sebastes mentella
• Online Access: http://dx.doi.org/10.1139/f82-224; http://www.nrcresearchpress.com/doi/pdf/10.1139/f82-224

The distribution of Northwest Atlantic beaked redfishes, Sebastes mentella and S. fasciatus, has been confused for the past several decades. Sebastes fasciatus has been reported as having lower meristic counts than S. mentella. Meristic elements of 33 301 vertebrae, 22 622 anal fin ray, and 16 290 dorsal fin ray counts were utilized to examine the yearly, depth, and geographic variation of meristics in beaked redfishes. Data collected from specimens caught off West Greenland, Baffin Island, Labrador, Newfoundland, Quebec, and Nova Scotia were analyzed by 100-m-depth intervals. Temporal and depth variation were examined by the χ 2 -test of independence on meristic frequencies. Geographic variation was evaluated using the modes and mean values in the meristic frequency histograms. Cluster analysis of meristic frequencies displayed the dendrographic affinities and the distance matrix among division–depth blocks.Temporal variation indicated a mixture of vertebral frequency patterns which varied with depth and area. Depth variation and geographic clines were found for each of these meristic characters; the shallow and southern waters were dominated by counts of 29, 14–13, and 7 for vertebrae, dorsal fin rays, and anal fin rays, respectively, whereas deep and northern waters were dominated by 30, 15–14, and 8–9. These results suggested that S. fasciatus occurs on the Nova Scotian Shelf and Grand Bank whereas S. mentella is largely found in Baffin Bay, Labrador waters, and the Gulf of St. Lawrence. The common names of S. mentella and S. fasciatus are discussed. Additionally, five hypothetical stocks of beaked redfishes based on meristic patterns are proposed for management purposes.Key words: Sebastes mentela, S. fasciatus, redfish, meristic variation, distribution, cluster analysis