American Oceans

Spiny Dogfish

Spiny dogfish, also known as Squalus acanthias, are a type of shark that many people have heard of.

Spiny Dogfish (Squalus acanthias) at the south coast of Norway

They are a common species of the Squalidae family of sharks and are part of the Squaliformes order. These sharks are known for their distinctive features, including two spines (one anterior to each dorsal fin) and no anal fin.

Spiny dogfish are slim and have a narrow, pointed snout with characteristic white spots. They are gray above and white below, with two dorsal fins that have ungrooved large spines.

Males grow up to 3.3 feet, and females grow up to 4 feet. Like all sharks, dogfish grow slowly, mature late in life, and live a long time (35 to 40 years). These sharks are found in waters all over the world and tend to live in deep, offshore habitats.

The spiny dogfish is one of the most widely known species of the Squalidae family. These sharks are abundant along northern Atlantic and Pacific coasts and are caught primarily with otter trawls and sink gill nets.

They are used in the popular British dish “fish and chips” as well as marketed for their oil and as fish meal. While these sharks can cause tremendous damage when entangled in commercial nets, they pose little if any threat to humans.


Spiny dogfish (Squalus acanthias) is a shark species that belongs to the Squalidae family of sharks, which is part of the Squaliformes order.

spiny dogfish shark

This shark species is also known as spurdog, mud shark, or piked dogfish. It is one of the best-known types of dogfish species due to its unique physical characteristics.

Physical Characteristics

Spiny dogfish has a pointed snout and two dorsal fins with sharp spines, one anterior to each dorsal fin. It does not have an anal fin, which distinguishes it from other shark species.

The shark’s coloration is dark gray or brownish on its back and white on its underside. The spiny dogfish’s body is covered with small, sharp scales called dermal denticles that are used for protection against predators.

The shark’s tail is slender and elongated, which helps it swim through the water with ease. Spiny dogfish can grow up to 4 feet in length and weigh up to 20 pounds. They have a lifespan of up to 100 years, making them one of the longest-lived shark species.

Behavior and Habitat

Spiny dogfish is a highly migratory species that can be found in shallow waters, the continental shelf, and further offshore habitats.

spiny dogfish shark

They are known to travel long distances, and one individual tagged in Washington made a 5,000-mile journey to Japan. Spiny dogfish is a viviparous species, meaning that they give birth to live young. The shark’s gestation period is the longest of any vertebrate, lasting 22 to 24 months.

Spiny dogfish feeds on a variety of prey, including small salmon, sea eel, red hake, goosefish, crabs, and crustaceans.

They are also known to feed on jellyfish, cod, and smaller sharks. Mature females are known to migrate to shallower waters during the summer months to give birth to their young.

Spiny dogfish is a prey species for larger sharks, orcas, and whales. They are also hunted by humans for their meat, which is commonly used in Europe as the fish in “fish and chips.” Spiny dogfish has venomous spines that can cause wounds if not handled properly.

Scientific Classification

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Chondrichthyes
  • Order: Squaliformes
  • Family: Squalidae
  • Genus: Squalus

Common Names

  • Spiny dogfish
  • Spurdog
  • Mud shark
  • Piked dogfish
  • Rock salmon


Spiny dogfish are opportunistic feeders, which means they eat a variety of prey depending on what is available in their habitat. They are known to feed on bony fishes, smaller sharks, octopuses, squid, crabs, and shrimp.

The diet of spiny dogfish varies based on their size, with smaller individuals primarily feeding on crustaceans and larger dogfish preferring jellyfish, squid, and schooling fish.

Cod is one of the predators of spiny dogfish, but spiny dogfish are also known to prey on cod. Spiny dogfish are also preyed upon by red hake, goosefish, other spiny dogfish, larger sharks, seals, and orcas.

Spiny dogfish are important economically for humans, as they are used for their oil and as fish meal. They are also a popular laboratory animal. In some areas, such as Europe, spiny dogfish is a popular food fish.

In general, spiny dogfish consume around 3% of their body weight each day. They are known to be highly migratory, with one individual tagged in Washington making a 5,000-mile journey to Japan.

Spiny dogfish have the longest pregnancy of any vertebrate, lasting 22 to 24 months, or two years. During this time, eggs develop in the female, gaining nutrients from yolk sacs.

Overfishing and Fishery Management

History of Overfishing

The Atlantic Spiny Dogfish (Squalus acanthias) has been overfished for decades due to its slow growth and low reproductive rate.

spiny dogfish fishing

In the 1990s, the population of Atlantic Spiny Dogfish declined to critically low levels, leading to the implementation of a fishery management plan to rebuild the population. Despite the efforts to rebuild the population, the fishery was reopened in 2000, leading to a decline in the population once again.

Fishery Management Plan

The Atlantic Spiny Dogfish Fishery Management Plan is jointly managed by the Mid-Atlantic and New England Fishery Management Councils.

The plan aims to rebuild the population of Atlantic Spiny Dogfish while allowing for sustainable commercial and recreational fishing. The National Marine Fisheries Service (NMFS) oversees the implementation of the plan and sets regulations to ensure the goals of the plan are met.

Commercial and Recreational Fishing Regulations

The NMFS sets commercial quotas and trip limits for the Atlantic Spiny Dogfish fishery. In 2023, the commercial quota was decreased by 59% compared to fishing year 2022 to prevent overfishing.

The possession limit for commercial fishing is 4,000 pounds per trip, and the use of gillnets is prohibited. Recreational fishing regulations vary by state, but the Atlantic States Marine Fisheries Commission recommends a possession limit of one Atlantic Spiny Dogfish per person per day.


The NMFS requires fishermen to report all Atlantic Spiny Dogfish catches and discards. This information is used to monitor the population and ensure that the fishery is sustainable. The NMFS also conducts stock assessments to determine the health of the population and adjust regulations as necessary.

Overall, the Atlantic Spiny Dogfish fishery is heavily regulated to prevent overfishing and rebuild the population. While the fishery has faced challenges in the past, the implementation of the Fishery Management Plan and strict regulations have led to improvements in the population.

However, continued monitoring and adjustments to regulations will be necessary to ensure the long-term sustainability of the fishery. The Atlantic Spiny Dogfish can be found in the Eastern Atlantic, Iceland, Greenland, and Argentina.

Conservation Status

The conservation status of spiny dogfish is a topic of concern due to their vulnerability to overfishing. The International Union for Conservation of Nature (IUCN) lists the species as “Vulnerable” globally. In the North Atlantic, the stock is considered to be overfished, and the population is at historically low levels.

Stock Assessment

According to NOAA Fisheries, spiny dogfish are managed as a single stock in the North Atlantic. The Mid-Atlantic Fishery Management Council and the New England Fishery Management Council jointly manage the species through the Interstate Fishery Management Plan for Spiny Dogfish. The stock is assessed regularly using a variety of methods, including surveys, commercial landings data, and scientific studies.

Conservation Efforts

Conservation efforts for spiny dogfish are focused on reducing fishing pressure and protecting their habitat. The commercial and recreational fishing of spiny dogfish is regulated to prevent overfishing.

The Atlantic States Marine Fisheries Commission and NOAA Fisheries have implemented measures to reduce the catch of spiny dogfish, including size limits, trip limits, and quotas.

In addition to fishing regulations, efforts are being made to protect spiny dogfish habitat. The species is known to form large schools and is migratory, making it difficult to protect their habitat. However, some areas have been designated as Essential Fish Habitat (EFH), including areas in the North Atlantic and North Pacific.

Overall, the conservation status of spiny dogfish is a concern, and efforts are being made to protect the species from overfishing and habitat degradation. The collaboration between government agencies and the fishing industry is crucial to the success of conservation efforts for this chondrichthyan species.


Spiny dogfish, also known as Squalus acanthias, are a type of shark that are commonly found in the Atlantic Ocean. They are often considered a nuisance by fishermen, but they have a variety of uses that make them valuable in different industries.

Commercial Uses

Spiny dogfish is a commercially important species that is used for a variety of purposes. Its meat is sold fresh or frozen, and is often used to make fish and chips in Europe.

In the United States, spiny dogfish is not commonly consumed, but it is used as bait for other commercial fisheries. The liver of the spiny dogfish is also used to produce oil, which is used in the production of cosmetics, lubricants, and leather tanning.

Culinary Uses

Spiny dogfish is a popular ingredient in fish and chips in Europe. Its meat is firm and white, and has a mild flavor that is similar to cod. It is also used in stews, soups, and other dishes.

In some countries, such as France, spiny dogfish is considered a delicacy and is served in high-end restaurants.

However, it is important to note that spiny dogfish is a slow-growing species that is vulnerable to overfishing. As a result, it is important to consume spiny dogfish responsibly and to support sustainable fishing practices.

Other Uses

In addition to its commercial and culinary uses, spiny dogfish has other uses as well. Its skin is used to make leather, while its fins are used to make shark fin soup in some cultures.

However, it is important to note that the practice of shark finning is controversial and has been banned in many countries due to its impact on shark populations.

Overall, spiny dogfish is a versatile species that has a variety of uses in different industries. However, it is important to consume spiny dogfish responsibly and to support sustainable fishing practices to ensure the long-term viability of this species.

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