Incidence of Subcaudal Melanaphores in Pre-extrusion Larvae of Redfish Species in the Newfoundland-Labrador Area
Journal of Northwest Atlantic Fishery Science
Pre-extrusion larvae of female redfish from the Newfoundland-Labrador area in 1958-66 were examined for the presence or absence of subcaudal melanophores. The larval samples from the sharp-beaked mentel/a-type redfish were readily separated into two groups. one with all or nearly all of the larvae possessing subcaudal melanophores and recognized as Sebastes tescietus, and the other tending to have a small fraction or none of the larvae with these melanophores and recognized as Sebastes
... s Sebastes mentel/a. Moreover, the larvae of S. fasciatus had on the average a greater number of subcaudal melanophores which were also usually larger than those of S. mentel/a. However. the presence of these melanophores in many of the North American S. mentel/a contrasts with the reported absence of subcaudal melanophores in larvae of Icelandic and Northeast Atlantic and of the North Atlantic oceanic populations of S. mentel/a. The female parents of larvae assigned to S. fasciatus had significantly lower vertebral. anal fin-ray and dorsal fin-ray numbers than those of larvae assigned to S. mentel/a. The occurrence of subcaudal melanophores in Sebastes marinus larvae generally resembled that in the North American S. mentel/a (as distinct from S. fasciatus) except that the former tended to have more larvae with melanophores than the latter. The meristic characteristics of the S. marinus parents more closely resembled those of S. mentel/a than those of S. tescietus. butthe fin-ray numbers in S. marinus tended to be lower than in S. mentel/a. In the Northwest Atlantic area from Flemish Cap to southern Labrador, the spawning females of S. mentel/a appear to live deeper and extrude larvae earlier in the year than those of S. fasciatus and S. marinus. These differences in distribution and biology and the occurrence of large immature S. mentel/a in the northern part of Newfoundland-Labrador area have management implications which are discussed.