They live up to years of age. Food Habits Dogfish have earned a bad reputation among fishermen for their voracious appetites. They are known to drive off commercially caught fish including mackerel and herring, while consuming large numbers of them. Spiny dogfish have been observed biting through nets to get at fishes, releasing many of them in the process. Schooling pelagic fishes make up the majority of the diet of the spiny dogfish.
These include herring, menhaden, capelin, sand lance, and mackerel. Other consumed species include wolffish and flatfishes, as well as squid, jellyfish, shrimps, crabs, octopus, and sea cucumbers.
It is believed that spiny dogfish rarely feed during the winter months when they stay in deeper waters based upon their very thin appearance in early spring in coastal waters.
Reproduction Mating typically occurs in offshore waters with fertilization occurring internally. This is followed by ovoviviparous development.
After month of development, the membrane providing nourishment to the embryo breaks down. This leaves the yolk-sac to provide nourishment during the remaining months of gestation. This species is thought to have the longest gestation period of any vertebrate up to 24 months. The young are born head-first with cartilaginous sheaths on the spines to protect the mother from injury. Litter sizes average but varies between 1 and The newborn pups range from inches cm in length.
Predators Spiny dogfish are been documented in the stomachs of cod, red hake, and goosefish, as well as other spiny dogfish. Larger species of sharks as well as seals and killer whales, although in fewer numbers, also feed on the spiny dogfish. Firsthand observation of a spiny dogfish giving birth in the wild near Rockport, MA August The spiny dogfish was originally described as Squalus acanthias by Karl Linneaus in However, many synonyms referring to this species have been used in past scientific literature.
Discover Fishes Squalus acanthias. Spiny Dogfish Spiny Dogfish. Order: Squaliformes Family: Squalidae Genus: Squalus Species: acanthias Common Names English language common names include spiny dogfish, blue dog, common spinyfish, darwen salmon, dogfish, grayfish, Pacific dogfish, piked dogfish, rock salmon, spiky dog, spotted spiny dogfish, spring dogfish, spur dogfish, spur dog, victorian spotted dogfish, white-spotted dogfish, and white-spotted spurdog.
Importance to Humans Spiny dogfish. In defense, the spiny dogfish can arch its back and inject venom into its predators from its dorsal spines. Males reach maturity after about 11 years; females reach maturity after 18 to 21 years.
In winter, pairs will mate in offshore waters. Once the eggs are fertilized, a protective shell forms and protects the embryo. After 4 to 6 months, the shells are shed and the young gestate for 18 to 20 more months, for a total of 2 years spent in the womb. An average of 6 pups are born at a time. Most spiny dogfish live 20 to 24 years, but some have lived to 50 years old. As the stock began to improve, landings were increased to 21 million pounds in In , commercial landings were estimated at Discards have remained around 11 million pounds over the past decade and have declined in recent years.
Canadian and foreign landings have also decreased significantly in recent years. It is anticipated that the Canadian dogfish harvest will not increase in the near future given the lack of demand for the product and the subsequent closure of Canadian spiny dogfish processors. The Stock Assessment Update indicates the population is not overfished nor experiencing overfishing. The spawning stock biomass estimate of million pounds is slightly above the SSB threshold of million pounds, while the fishing mortality estimate 0.
Despite remaining above the threshold, biomass has declined in recent years, requiring a significant reduction in to ensure that overfishing does not occur.
Both the Commission and federal plans use a fishing mortality rate to set annual quotas and trip limits. The spiny dogfish commercial fishery, which operates from May 1 through April 30, is managed though an annual commercial quota, which is further allocated by state shares.
The southern state shares are allocated as follows: New York 2. Any overages from the previous fishing seasons are paid back by the region or state in the following season.
Atlantic spiny dogfish can be found anywhere from the surface to more than 3, feet m deep. Spiny dogfish were named after their tendency to hunt in dog-like packs. Female spiny dogfish are pregnant for 18 to 24 months, giving them one of the longest gestation periods of any vertebrate.
Spiny dogfish have sharp, venomous spines in front of both dorsal fins. Click here or below to download hands-on marine science activities for kids. Home Marine Life. Fun Facts About Spiny Dogfish 1. Learn More.
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