Research Document - 2011/084
A pre-COSEWIC assessment of thorny skate (Amblyraja radiata Donovan, 1808) on the Grand Bank, Newfoundland Shelf, Labrador and northern waters
By Simpson, M.R., L.G.S. Mello, C.M. Miri, M. Treble, and T. Siferd
Abstract
This paper presents the most recent information regarding the life history and fisheries of thorny skate (Amblyraja radiata Donovan 1808) in Newfoundland and Labrador waters, and includes available data from Arctic waters. The primary purpose of this paper is to provide this information to the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) for use in formulating and evaluating conservation and management strategies for this species in terms of risk of extinction.
Independent data series based on spring and fall bottom trawl research survey catches and commercial fisheries statistics covering the distribution of A. radiata in NAFO Div. 2HJ3KLMNOPs indicate that this species is widely distributed from Baffin Bay to the Laurentian Channel, but that its main stock component is consistently found on the Grand Bank over time. Research survey indices of relative abundance and distribution varied little since the 1970s in Div. 3OPs (southwestern Grand Bank and Laurentian Channel); whereas in Div. 3LN (northern and eastern Grand Bank), A. radiata experienced considerable declines in abundance and area occupied during the early 1990s. However, common features were also detected throughout the study area; notably in terms of thermal preferences and a recent increasing trend in indices of relative abundance. The latter constitutes a first sign of stock recovery in most areas during the last decade.
Several important aspects of the life history and fisheries of A. radiata in the study area remain uncertain or are lacking; largely due to partial knowledge of population structure and biology, as well as the impacts of commercial fisheries and environmental variability.
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