Spiny dogfish or 'spurdogs' as they are sometimes called, are relatively small squaloid sharks, characterized by the presence of two dorsal fins with spines on their leading edges and no anal fin. They often have a light scattering of small white spots on their torso, especially along their lateral lines.

Their slow rate of maturity (upwards of twenty years) combined with extremely long gestation (more than two years), leave them extremely vulnerable to overexploitation.


Spiny Dogfish have a wide but fragmented range. The largest subpopulations occur in coastal habitats on both sides of the North Atlantic. There are smaller isolated subpopulations in the Southwestern Atlantic and the Eastern Pacific along the coastlines of South America as well as the southern tip of Africa, Southern Australia and around New Zealand.

Spiny dogfish populations in the North Pacific have recently been reclassified as a separate species Squalus suckleyi - the North Pacific Spiny Dogfish. Although S. suckleyi faces similar obstacles, it is not included in this account.


The principal threat to this species worldwide is over-exploitation, by target and bycatch fisheries. This is a valuable commercial species in many parts of the world, caught in bottom trawls, gillnets, line gear, and by rod and reel.

France was the largest importer of dogfish meat within the EU from 1990-1994, importing an annual average of 5,000 tonnes (98% spiny) with the UK as their top European supplier. During 1988-1994, Norway was the largest of nine non-EU suppliers to the EU of fresh or chilled spiny dogfish, followed by the US. As European stocks decline, demand is being met by frozen imports from 25 countries, dominated by the US and Argentina.

According to the Food and Agricultural Organization (FAO), dogfish catches reached a peak in 1972 (73,500 t) then declined and stabilized in a range between 36,000 and 51,000 t in the 1990s. Most of the catch reported to FAO comes from the North Atlantic, with minor amounts reported from the Mediterranean and Black Seas. There are, however, some data discrepancies: in 1999, the US landed nearly 15,000 t of spiny dogfish and 9,800 t was landed from ICES areas, most of this by the UK fleet (UK fisheries statistics report over 9,000 t landed), yet FAO reports 1999 global catch at 22,756 t with the largest catches coming from Canada (5,536 t) and Norway (1,461 t) (FAO 2000) (note that some statistics will include the North Pacific Spiny Dogfish Squalus suckleyi).

Locally high biomass initially supports large catches, but most large-scale spiny dogfish fisheries have depleted populations and collapsed (Ocean Wildlife Campaign 1996). An aggregating habit makes it possible for fishers to continue to target highest value mature females even after stocks have been depleted to a few percent of baseline. The species is also taken as a bycatch in mixed species fisheries, meaning that fishing pressure can continue even after stocks have been so seriously depleted that they can no longer support viable fisheries.

There are potential impacts on spiny dogfish associated with habitat loss and degradation. Coastal development, pollution, dredging and bottom trawling affect coastal or benthic habitat on which spiny dogfish or their prey rely (ASMFC 2002).


Despite several decades of warnings of unsustainable fishing pressure and reported steep stock declines, very few conservation or management measures are in place for spiny dogfish; measures in place have not been effective in terms of rebuilding populations. A notable exception may be New Zealand, where quotas have been introduced to limit catches to sustainable levels in response to the first signs of fishery development to meet European demand for meat. Spiny dogfish were brought under the New Zealand Quota Management System in October 2004 (M. Francis, pers. comm).

Holden (1968) first warned that part of the Northeast Atlantic stock was over-exploited, but there is still no effective management in this region despite wide-spread recognition that fishing levels are unsustainable and several parts of the stock have collapsed. A minimum landing size established in Norway in order to protect mature females is of limited value for a migratory species that is intensively fished in other parts of its range. Total Allowable Catches in EU waters, first established in 1998, have consistently exceeded recent landings and do not appear, therefore, to have had any constraint upon current unsustainable levels of fishing pressure. This fishery needs to be closed if the stock is to recover, ICES recommended a zero quota in 2006, but this advice was not heeded by the EU.

In the Northwest Atlantic, the 1999/2000 US federal dogfish rebuilding plan has yet to reverse population decline and fishing mortality targets continue to be grossly exceeded.

Federal Fishery Management Councils in the eastern US developed a spiny dogfish rebuilding plan in the late 1990s coincident with the stock being officially declared overfished. Low priority and controversy over cuts led to serious delays. Implemented in mid 2000, the plan aimed to rebuild the population through a low fishing mortality target (F=0.03) and corresponding quota (four million lbs) and trip limits (300 to 600 lbs for two periods) that would discourage targeted fishing and yet allow some landing of incidental catch. Once that the ten-year legal limit to recover the population became impossible, federal law allowed the rebuilding period to be extended, opening the plan up for relaxation of measures.

As Federal measures developed, the dogfish fishery shifted into state waters (within three miles from shore). Continued state fisheries have undermined the federal plan ever since. Most notably, Massachusetts, the Atlantic state with the largest directed dogfish fishery, adopted a 2000 state quota at nearly twice the Federal allotment for the entire Atlantic and excessive possession limits that allowed for continued directed dogfish fishing. Under the federal plan, overages are not deducted from the subsequent year?s quota.

In late 2002, the Atlantic States Marine Fisheries Commission (ASMFC) adopted a federally compatible dogfish rebuilding plan for state waters. In early 2003, however, the ASMFC rejected scientific advice and accepted a Massachusetts proposal to more than double the quota (to 8.8 million lbs) and increase trip limits by an order of magnitude (to 7,000 lbs) to allow directed dogfish fishing. The ASMFC did impose scientifically defensible limits for the 2004 fishing year (beginning in May), but rejected the 2005 advice for a 50% quota cut for 2006 in favour of the status quo (4 million lbs). This advice, from a joint state and federal technical committee, was also rejected by the New England Fishery Management Council, but adopted by the Mid-Atlantic Fishery Management Council (MAFMC). The decision on catch limits for the 2006 fishing season now lies with the NMFS, but pressure to relax recovery efforts is increasing due to the movement of a larger percentage of the population to nearshore waters and therefore fishing gear. The ability to set catch limits for a multi-year period (3 to 5 years) is currently being considered by both state and federal authorities and may be realized as soon as this year.

Canada began restricting Atlantic dogfish catch in May of 2002, following a significant increase in landings in years just prior. The government capped 2002 commercial landings at 2,500 metric tons for the fixed gear groundfish sector off Nova Scotia and in the Bay of Fundy, based on landings history at the time. In addition, bycatch caps for other fisheries consistent with historical landings and an additional 700 mt for a cooperative industry sampling program were granted. The Canadian government has stated that the caps are aimed to limit harvest while future sustainable catch levels are investigated. The Canadian government intends to maintain dogfish catches at roughly 3,200 mt for directed fishing and research while they collect data and develop their own population assessment, expected by 2007 (Campana 2002, pers comm).


Citation: Fordham, S., Fowler, S.L., Coelho, R.P., Goldman, K. & Francis, M.P. 2016. Squalus acanthias. The IUCN Red List of Threatened Species 2016: e.T91209505A2898271. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T91209505A2898271.en. Downloaded on 22 September 2017.



After decades of mismanagement, almost all governing bodies (with the exception of New Zealand) have proven themselves completely incapable of protecting spiny dogfish stocks.

Organizations such as the Shark Alliance continue to lobby for change. Please support their initiatives however possible.

Although the issues may seem too large to tackle on a personal level, you can create change:

  1. Never order dogfish. In British fish and chip shops, spurdog is marketed under the name FLAKE or ROCK SALMON.

  2. Politely suggest that restaurants remove shark from their menu and explain why.

  3. Never buy medications or supplements that contain shark cartilage.

  4. Never buy cosmetics that contain shark products.

  5. Encourage your friends to follow your example.