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Maturity, size at age and predator–prey relationships of winter skate Leucoraja ocellata in the southern Gulf of St Lawrence: potentially an undescribed endemic facing extirpation
Author(s) -
Kelly J. T.,
Hanson J. M.
Publication year - 2013
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/jfb.12030
Subject(s) - biology , fecundity , skate , population , zoology , sexual maturity , fishery , ecology , chondrichthyes , predation , demography , sociology
The goals of this study were to document the size and age structure, size at maturity, ovarian fecundity and diet of the endangered population of winter skate Leucoraja ocellata that resides in the southern Gulf of St Lawrence ( SGSL ). The maximum size observed for SGSL L. ocellata was 68 cm total length ( L T ) but >99% of animals caught were <60 cm L T . Fifty per cent of male and female L. ocellata were fully mature at 40 and 42 cm L T , respectively, age c . 5 years. The oldest individual caught was age 11 years, but 98% of the 561 individuals examined were ≤age 8 years, indicating a short reproductive life span. Ovarian fecundity was low; no more than 29 ova >10 mm diameter were ever observed. At 40 cm L T , the diet changed from one dominated by shrimp Crangon septemspinosa and gammarid amphipods to one dominated by fishes (mainly sand lance Ammodytes spp. and rainbow smelt Osmerus mordax ) and Atlantic rock crab Cancer irroratus . Sufficient differences were observed between SGSL L. ocellata and other populations in their size‐at‐maturity pattern and maximum size to propose the taxonomic re‐evaluation of the population.