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Occurrence of sharks, rays and rabbit fish in the Greater North Sea – and catches in Swedish fisheries

Börjesson, Patrik and Norén, Katja and Valentinsson, Daniel (2022). Occurrence of sharks, rays and rabbit fish in the Greater North Sea – and catches in Swedish fisheries. (NL, NJ) > Department of Aquatic Resources, Sveriges lantbruksuniversitet. Aqua reports ; 2022:14
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Abstract

This report was written in response to a request from the Swedish Agency for Marine and Water Management to update an earlier technical note from SLU Aqua “Occurrence of skates and rays in northern European waters and catches in Swedish fisheries in the Skagerrak/Kattegat and the eastern North Sea”. The aim was to provide a comprehensive overview of elasmobranchs present in Swedish waters and to what extent these species are caught in Swedish fisheries. To describe the occurrence and spatial distribution of sharks, rays and rabbit fish we used fisheries-independent survey data from 1967–2020, as well as data from the national on-board observer program and official landing data. During this time a total of 21 species of sharks, rays and rabbit fish were reported from the Skagerrak, Kattegat and the Sound. Seven of the species were common in both the fishery independent and the commercial data supporting that they are native to Swedish waters. These species included three shark species; velvet belly (Etmopterus spinax), lesser spotted dogfish (Scyliorhinus canicula) and spurdog (Squalus acanthias); three species of rays; starry ray (Amblyraja radiata), thornback ray (Raja clavata), and sailray (Rajella lintea); and the rabbit fish (Chimaera monstrosa). The round ray (Rajella fyllae) was also relatively common in survey catches from the deeper parts of the Skagerrak. All common species were present year round, but spurdog also showed a seasonal trend, being more common along the Norwegian coast and in offshore part of the Skagerrak in the first quarter, and closer to the Swedish coast in the third and fourth quarter. There are no longer any targeted fisheries for elasmobranchs by Swedish vessels but by-catches occur, predominantly in demersal trawl fisheries in the deeper parts (> 200 m) of Skagerrak and the Norwegian trench where a majority the observed hauls had by-catch of one or more species. Usage of a sorting device (grid) in the Nephrops and Pandalus trawl fisheries appear to reduce the amount of by-catches. Historical and anecdotal information suggest that by-catch of spurdog in gillnets could be significant, but as landing were prohibited in 2010, no data is available since then. Starry ray and spurdog represents > 75 % of the estimated total catch weight of shark and rays combined. More than 90 % of elasmobranchs was discarded, which is not surprising given that landing of spurdog, starry ray, common skate and thornback ray are prohibited in 3a. Sailray is the only species landed to some extent (few tonnes per year) by Swedish vessels during the last five years. Swedish landings of sailray mainly come from the Pandalus fishery and from demersal trawl fishing without grids in the deeper parts of Skagerrak.

Authors/Creators:Börjesson, Patrik and Norén, Katja and Valentinsson, Daniel
Title:Occurrence of sharks, rays and rabbit fish in the Greater North Sea – and catches in Swedish fisheries
Series Name/Journal:Aqua reports
Year of publishing :2022
Number:2022:14
Number of Pages:41
Publisher:Institutionen för akvatiska resurser, Sveriges lantbruksuniversitet
ISBN for electronic version:978-91-576-9969-5
Language:English
Publication Type:Report
Article category:Other scientific
Version:Published version
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Fish and Aquacultural Science
Keywords:elasmobranch, shark, skate, ray, rabbit fish, groundfish survey, bottom trawl, spatial distribution, landings, observer data
URN:NBN:urn:nbn:se:slu:epsilon-p-116702
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-116702
ID Code:27572
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Aquatic Resources
Deposited By: SLUpub Connector
Deposited On:19 Apr 2022 11:25
Metadata Last Modified:21 Apr 2022 14:57

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