General information
Spurdog Squalus acanthias has a worldwide distribution in temperate and boreal waters, and occurs mainly at depths of 10–200 m. In the NE Atlantic, this species is found from Iceland and the Barents Sea southwards to the coast of Northwest Africa. In Icelandic waters it is mainly found in the warmer waters off S-Iceland.
The fishery and landings
Since 2017 a general ban of target fisheries on spurdog, porbeagle Lamna nasus and basking shark Cethorhinus maximus is in place (https://www.reglugerd.is/reglugerdir/allar/nr/456-2017).
Like other sharks and skates spurdog used to be incidental bycatch. Landings have been mainly reported from the gillnet fishery. In 2002, there are unusually high landings reported in the longline/hook fishery, and in the gillnet fishery the year after. In the years leading up to 2017, landings rarely exceeded 60 tonnes (Figure 1).
Survey data
Distribution and occurrence
Spurdog is not a common catch in MFRI groundfish surveys. In the spring survey (IS-SMB), occasional single large catches have occurred off the south coast (Figure 2 a). The latest single large catch was in year 2002 (650 kg in one tow). In the autumn survey (IS-SMH), spurdog is also scarce and distributed over a wider area than in IS-SMB. In the gillnet survey (IS-SMN), spurdog is mainly caught at stations off the south coast (Figure 3). At several locations, spurdog has been a regular catch in the gillnet survey.The main occurrence of spurdog in these surveys is at depths of 0 -200 m. Spurdog was caught on average at ~ 3 % of stations. After 2002 it is caught only at few stations each year (Figure 4). In the gillnet survey the spurdog used to be relatively frequent bycatch but the frequency has decreased since 2001 and remained at ver low levels since 2010 (Figure 5).
Length distributions
Survey information on length distribution indicate that most specimens are at 60-90 cm TL. On average, spurdog is 83 cm in the gillnet survey (IS-SMN) and 80.5 cm in IS-SMB (Figure 6).
