Dogfish Shark
The Dogfish Shark has the greatest population of any shark in the world. Because it is the most common shark, it is also the most well-known to people who live near oceans. It is one of the few sharks processed by commercial fisheries. If you order fish and chips in Europe, the chances are good that you will be eating the meat of this shark. They are also marketed by the names of rock shark, rock salmon, and rock cod.
The Dogfish Shark got its name from the fact that it travels together in large schools of hundreds and even thousands of fish. The Spiny Dogfish is the most common among dogfish. They grow to be around five feet in length and weigh around twenty pounds. Scientists estimate that a dogfish shark will live anywhere from twenty-five to one hundred years. Spiny Dogfish do not mature enough for reproduction until they are quite old--estimates range from twenty to thirty-five years of age. Females are larger than males and they produce eggs which hatch in their bodies, then giving birth to live young. It is known that baby Dogfish Sharks are between eight and twelve inches young, and that there are on average seven pups in a litter. The mother Dogfish Shark is pregnant for 24 months.
Because it takes so long for a Dogfish Shark to reproduce, there is some concern among conservationists that if certain areas get fished out, it will be easy for this breed of shark to be endangered. Right now there are so many of these sharks in some locations, especially in British Columbia and Alaska, that they are regularly caught in nets designed to catch other fish. On the Eastern Atlantic Coast of the United States, a law was passed limiting the amount of Dogfish Sharks that can be taken each year.
This shark lives in temperate and sub-Arctic waters, with especially high numbers between Baja, California and Alaska. They are a nuisance to fishermen, often damaging fishing equipment, destroying hooked fish or chasing fish away. The Dogfish Shark is often caught by those trying to catch pollock, halibut, Pacific cod or Greenland turbot. The greatest amount of commercial fishing for the Dogfish Shark is in the waters off Washington State and Alaska.
The sharks themselves prey on herring, smelt, sand lance, and young salmon. Their diet is known to include a minimum of twenty-seven different fish and thirteen kinds of invertebrates. They are very aggressive predators and young Dogfish Sharks have been seen pursuing much larger fish. Because they travel in such large schools, they often feed on huge groups of other fish entering an area and cleaning it out very quickly.
These sharks travel long distances, usually in pursuit of ideal water temperatures and large schools of fish to eat. It was reported that one radio-monitored Dogfish Shark swam all the way from the State of Washington to Japan, almost 5,000 miles.