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Status and Fisheries Advice

The northeast Atlantic stock of spiny dogfish has provided the basis for a valuable fishery for more than a hundred years. Throughout the 40-year period from 1950-1990, it is reported to have supported annual landings of 30,000-60,000 tons.  

Knowledge about the population is deficient, but preliminary analyses indicate that the population gradually declined throughout this period and was by1990 only 20% of what it was just after World War II. During the last 20 years, fishing effort has been reduced significantly, and the population appears to have stabilized at this relatively low level.

Spiny dogfish grow slowly, are late to become sexually mature, and give birth to only 7-11 pups every other year.  It may take many years before the spawning stock can recover even if there is no fishing pressure. Therefore, ICES recommends that no direct fisheries be conducted for spiny dogfish fishery during 2012, and that the by-catch level be held as low as possible.

In Norwegian waters, the condition of the spiny dogfish population is uncertain. It is unclear which parts of the larger population utilize Norwegian coastal waters.  Also unclear, is the extent to which their occurrence in Norwegian waters is linked to important processes in the population's life cycle, such as feeding, mating, and giving birth to live offspring.

Fisheries and Management

Spiny dogfish have long been sought after for both liver oil and fish meat, however they were often considered a problem — due their sheer abundance, their sharp poisonous spines, and their rough sandpaper-like skin  — when other fish species are targeted.  Traditionally, the United Kingdom, Ireland, France, and Norway have conducted the largest fisheries for spiny dogfish in the northeast Atlantic.  Directed fisheries — with long lines and nets — have been conducted in the North Sea, waters west of Scotland, the Irish Sea, and in Norwegian waters.  But, they are also landed as by-catch in trawl fisheries.

In recent years, more stringent regulations have been introduced, and several measures have made it less attractive to fish for spiny dogfish.  In both Norwegian and EU waters a ban was imposed on directed fisheries, and strict by-catch regulations were introduced. In Norway, there is a minimum-size limit for spiny dogfish, while the EU has a maximum- size limit.

In Norway, no directed fishing for dogfish has been allowed since 2007.  Up through 2010 exclusion was made for smaller coastal vessels fishing with conventional gear types in internal waters and Norway’s territorial seas.  Since 2011, however, the prohibition has applied to all vessel groups.  As dogfish often occur in large schools making it difficult to avoid capture, an exception  was also introduced  on to the general prohibition against  discarding to allow the release the of viable dogfish. When using conventional gear types fishers are allowed to have up to 20% by-catch of spiny dogfish per week.

The impact of fisheries on population trends strongly depends on which parts of the population are being exploited. With increased knowledge about catch composition and how the spiny dogfish population inhabits Norwegian waters, it will be possible to implement more targeted management measures, such as areal and seasonal restrictions, which reduce the potential impact on other fisheries. Hence, Norway’s Ministry of Fisheries and Coastal Affairs plans to established a research driven fisheries monitoring program for spiny dogfish to obtain the information needed to manage the stock responsibly.

Facts about Spiny Dogfish

Latin name: Squalus acanthias
Family: Squalidae
Maximum size: 123 cm
Life span: 25 years
Distribution: Global distribution in temperate regions of both northern and southern hemispheres
Primary spawning area: Undetermined
Spawning season: Free-living offspring are born year round, but production is believed to be lower during winter.
Diet: Largely zooplankton, including gelatinous plankton during juvenile pelagic stages.  Adults feed on juvenile fish including cod, herring, squid, shellfish, and others.
Characteristics: Has a moderately poisonous spike at the tip of both dorsal fins. These can be used to estimate the fish's age by counting the number of enamel rings which have been laid each year.
 

Status and Fisheries Advice

The northeast Atlantic stock of spiny dogfish has provided the basis for a valuable fishery for more than a hundred years. Throughout the 40-year period from 1950-1990, it is reported to have supported annual landings of 30,000-60,000 tons.  


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