Atlantic Spiny Dogfish (Squalus acanthias)

• Spiny dogfish abundance is rising, and overfishing is no longer taking place. Dogfish are no longer overfished.
• There is currently no large-scale, directed commercial fishery for spiny dogfish in the U.S. Small-scale directed fishing is permitted in east coast state waters. In federal waters, dogfish are only landed in fisheries that are targeting other species of fish and through recreational fishing.
• Shark is a low-fat source of protein and is high in selenium and vitamins B6 and B12. Shark may contain amounts of methylmercury in excess of the FDA's recommended limit for moms, moms-to-be, and young children. For more information, see EPA and FDA advice on what you need to know about mercury in fish and shellfish.
• Spiny dogfish is commonly used as the fish in "fish and chips" and is one of the world's most abundant species of shark.

Sustainability Status

Biomass: Biomass continues to increase, and as of 2006, large female biomass was about 60% of the level needed to support maximum sustainable yield (B_MSY). Management decisions are based primarily on assessment results for large females (greater than 31 inches).
Overfishing: No
Overfished: No
Fishing and habitat: Most Atlantic spiny dogfish is caught by bottom gillnets, with lesser amounts caught by trawls and hook gear.
Bycatch:  The Northeast Region Bycatch Priorities and Implementation Plan identified harbor porpoise, large cetaceans, bottlenose dolphin, pilot whale, common dolphin, and sea turtles as bycatch concerns for gillnets used to catch dogfish. The Dogfish FMP includes direct and indirect management measures aimed at reducing bycatch.
Aquaculture: There is currently no commercial aquaculture of spiny dogfish in the U.S.

Science and Management

The spiny dogfish fishery is jointly managed through the Mid-Atlantic and New England Fishery Management Councils' Spiny Dogfish Fishery Management Plan (FMP). The FMP covers the entire spiny dogfish population along the Atlantic coast of the U.S. and seeks to conserve spiny dogfish in order to achieve the optimum yield from the resource. Since the FMP was implemented in 2000, the quota has been set at levels intended to rebuild the stock. IN addition, trip limits have been set at low levels to discourage a targeted fishery. Recent information on the status of the stock shows that spiny dogfish is likely at or above its target biomass level. Therefore, the quota and trip limits may increase in the future. Currently, the Federal commercial fishery for spiny dogfish is an open access fishery. However, a Federal permit is required to participate. Recreational fishing only accounts for 3 to 4 percent of total landings.

Life History and Habitat

Life history, including information on the habitat, growth, feeding, and reproduction of a species, is important because it affects how a fishery is managed. Since sharks take many years to mature and only bear a small number of live young after a long gestation period, they are especially vulnerable to overfishing. Directed fisheries, which tend to catch mature females, appear to have had a significant impact on recruitment. NMFS has ended the directed fishery in federal waters to rebuild the stock.

• Geographic range: In the western North Atlantic from Greenland to Argentina (but most abundant from Nova Scotia to Cape Hatteras); in the eastern Atlantic from Iceland and the northern Russian coast to South Africa, including the Mediterranean and Black Seas.
• Habitat: Dogfish prefer temperatures from 45 to 55 degrees Fahrenheit. They are located inshore and offshore of the continental and insular shelf and upper slopes and are usually found near the bottom (but also in mid-water and at the surface). Dogfish are often found in enclosed bays and estuaries.
• Life span: Dogfish are long-lived - males live up to 35 years and females live up to 40 years.
• Food: Spiny dogfish eat a wide variety of prey. Herring, mackerel, squid, silver hake, and comb jellies constitute the major portion of their diets. Cod, haddock and flatfish are relatively uncommon by comparison. Spiny dogfish also prey on flatfishes, blennies, sculpins, jellyfish, polychaetes, sipunculids (group of marine worms), amphipods (small, shrimp-like crustaceans), shrimp, crab, snails, octopods, squids, and sea cucumbers.
• Growth rate: Slow; females grow larger then males
• Maximum size: Males grow up to 3.3 feet, and females grow up to 4 feet.
• Reaches reproductive maturity: Males reach maturity at 6 years and 23 inches; females reach maturity at 12 years and 30 inches.
• Reproduction: Females each have 2 to 12 eggs per season. They bear live young, after a gestation period of about 18 to 24 months, and typically produce 2 to 15 pups, with an average of 6.
• Spawning season: Winter
• Spawning grounds: Offshore waters
• Migrations: Related to water temperature. Dogfish are found in North Carolina and southern New England during spring and autumn but migrate northward to the Gulf of Maine-Georges Bank region and into Canadian waters in summer and southward in autumn and winter. Mature dogfish also school by size and sex.
• Predators: Predators of dogfish include a variety of shark species including sixgill, sevengill, leopard, and great white; a variety of larger fishes such as lancetfishes and some rockfish; and some marine mammals.
• Commercial or recreational interest: Both, although recreational only when preferred target species are unavailable
• Distinguishing characteristics: Dogfish are slim, with a narrow, pointed snout and characteristic white spots. They have two dorsal fins with ungrooved large spines and are colored grey above and white below.

Role in the Ecosystem

Spiny dogfish are top level predators. They are an opportunistic feeder, taking whatever prey is available. Smaller dogfish have been reported to feed primarily on crustaceans, while larger individuals tend to feed on fish. Fish, mainly schooling pelagic species, constitute 50% of their diet.

Despite possessing venom-delivering spines on each of its two dorsal fins, spiny dogfish are preyed upon by cod, red hake, goosefish, other spiny dogfish, larger sharks, seals, and orcas.

Additional Information

Dogfish are frequently caught as bycatch and discarded during groundfish operations, particularly in the Mid-Atlantic/southern New England area. Discard survival is high. Due to their low price per pound and need for special handling onboard, dogfish is often discarded if more valuable species are present.

Market name: Dogfish, Shark
Vernacular names: Spring dogfish, Spiked dogfish, Grayfish, Spur dog, Picked dogfish

Biomass

Biomass refers to the amount of spiny dogfish shark in the ocean. Scientists cannot collect and weigh every single shark to determine biomass, so they use models to estimate it instead. These biomass estimates can help determine if a stock is being fished too heavily or if it may be able to tolerate more fishing pressure. Managers can then make appropriate changes in the regulations of the fishery.

Spiny dogfish was classified as overfished in 1998. The targeted fishery for dogfish was ended in order to rebuild the stock. Spawning stock biomass has begun to increase over the past few years. The estimated biomass of spiny dogfish pups is much lower now than before the large-scale directed fishing that caught many of the largest and most productive females. Abundance of these large-sized females is increasing.

Landings

Landings refer to the amount of catch that is brought to land. Spiny dogfish was once considered to be an "under-utilized" species of relatively minor value to the domestic fisheries of the U.S. East Coast. With the decline of more traditional groundfish resources, some commercial fishermen directed their effort onto dogfish, thereby resulting in a nearly 10-fold increase in landings from 1987 to 1996. After the stock was declared overfished in 1998, management measures, including a quota and trip limits, were implemented to rebuild the stock, and landings subsequently decreased dramatically.

Note: The landings presented are domestic commercial landings.

Biomass and Landings

Are landings and biomass related? Landings are heavily dependent on biomass, management measures in the fishery, and fishing effort. This stock continues to be managed conservatively through a low fishing mortality rate target and no directed fishery in federal waters. Small-scale directed fisheries in state waters are permitted by the Atlantic States Marine Fisheries Commission (ASMFC).

Data sources:
Biomass and landings from 43rd Northeast Regional Stock Assessment Workshop (SAW) Assessment Report (2006)

Important Dates

Late 1980s – Fishery develops rapidly as international markets opened due to a rapid decline in European dogfish stocks
1990 – Landings at more than 30 million pounds (13,608 metric tons), tripling the landings in 1989
1995-1999 – Landings average 50 million pounds (22,680 metric tons) annually
1998 – Spiny dogfish classified as overfished as a result of an increased directed fishery, due to the decline in abundance of traditional groundfish
2000 – Spiny Dogfish FMP implemented, establishing management of Atlantic spiny dogfish fisheries and initiating stock rebuilding
2006 – Framework 1 to Dogfish plan implemented creating a mechanism for specification of multi-year management measures
2008 – Spiny dogfish estimated to be above the target biomass level

Notes and Links

General Information:
NOAA Northeast Fisheries Science Center Status of Fishery Resources off the Northeastern United States Spiny dogfish species information

NOAA's National Marine Fisheries Service (NMFS) Sustainability Species Identification for Spiny dogfish

NMFS Project Title: "Juvenile Bycatch and survival assessment of spiny dogfish (Squalias acanthias) in a Western Atlantic trawl fishery" (2006)

NOAA Technical Memorandum NFMS-NE-150: Essential Fish Habitat Source Document: Spiny Dogfish, Squalus acanthias, Life History and Habitat Characteristics (1999)

Gray's Reef National Marine Sanctuary Shark information

Fishery Management:
Mid-Atlantic Fishery Management Council Dogfish Fishery Management Plan History of Development

Code of Federal Regulations, Fisheries of the Northeastern U.S., Management Measures for the Spiny Dogfish Fishery

Stock Assessments:
43rd Northeast Regional Stock Assessment Workshop (SAW) Assessment Report (2006)