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Redfish (Ocean Perch)

The Prince of Wales, later Edward 1 VII, feasted on redfish in 1883 at the great international Fisheries Exhibition. The London Times reported on the luncheon he gave at the Royal Pavilion where:

...The greatest success was a well prepared impromtu, not on the card. It so happened that in the fish market was a consignment from Hull, of the Norwegian 'bergylt', little known in London but quickly identified by the Earl of Ducie, a leading authority on the subject of Norway fishing.... After being marinated for three hours with fine oil, this Norwegian fish was expertly treated with yolk of eggs and cream, fried in a light batter, and served at the moment of perfection. It remains to be said that nothing was left of the fish.

If redfish, members of the family Scorpaenidae, were virtually unknown in England in 1883, they were hardly more so in the Canada of that day. Yet in the twentieth century, redfish were to become the basis of an important fishery of Canada's Atlantic coast, with the United States currently acting as our most important customer for redfish products.

Description

Swimming in the deep waters at the edge of the great fishing banks and in deep channels carved in the ocean floor, redfish are mainly noted for the brilliant scarlet colour from which they take their name.

Aside from its deep colour, which ranges from orange to flame-red, sometimes with a brownish cast, the beaked redfish is distinguished from other spiny-rayed fish by a bony protrusion on the lower jaw, by a fan of bony spines that radiate out from around the gill cover, and by its large eyes.

Two types of redfish are known in the Northwest Atlantic, Sebastes mentella being the more common. It is found at depths of greater than 200 m, has a bright red colour, a relatively large eye and a long, well developed beak. Recent studies indicate that this species may, in fact, be further subdivided to include S. fasciatus. The S. marinus, usually found at depths of less than 240 m, is orange in colour rather than red, has a smaller eye and a small, blunt beak that is relatively weak. It generally grows to a much larger size than its close cousins. As far as the commercial fishery or fisheries management is concerned, the two (or three) species are managed together as a single unit.

Distribution

Although approximately 350 different kinds of scorpion fish are found throughout the world, including some commercially exploited species in the northern seas of the Atlantic and Pacific, diverse members of the family are more common in the shallow waters of tropical seas, particularly the Pacific and Indian oceans. These fish take their family name from poisonous spines found on tropical varieties.

In the North Atlantic, the family is most significantly represented by the redfish, also known as ocean perch or rosefish. These fish live in cool, northern waters (3° to 8°C) on both sides of the Atlantic. The commercial fishermen of Norway, Iceland and Greenland had been fishing for redfish long before they became of interest to Canadians, but now most of the northern nations exploit them.

The deep waters off New Jersey form the southern limit of the redfish range in the West Atlantic. Redfish usually inhabit waters from 100 to 700 m in depth in the Gulf of Maine, off the Nova Scotia and Newfoundland banks, in the Gulf of St. Lawrence, along the continental slope from the southwestern Grand Banks to Hamilton Inlet Bank, and in the area of Flemish Cap. They are also known off the southern coast of Baffin Island and off West Greenland, but they occur there in less abundance. Occasionally, in some areas of Maine, Newfoundland and the Bay of Fundy, where the waters are very cool, redfish have been caught in shallow waters near shore and around wharves. However, this is unusual.

Redfish generally are stratified by depth, with smaller fish being found in shallow and larger fish in deep waters. Redfish are known to move upward from the bottom at night, returning downward during the day. This movement is exploited by commercial fishermen who, using bottom trawls, get larger catches during the day than at night.

Because of the depth at which most of these fish live, tagging operations to study migration patterns are impractical in Canadian waters. The tagging of a shallow-dwelling population in the Gulf of Maine, however, indicated that there is probably very little migration. Seasonal surveys in the Gulf of St. Lawrence, on the other hand, indicate a possible winter migration to the mouth of the Gulf between Cape Breton and Newfoundland, with a spring return to the Gulf.

Reproduction

Redfish are viviparous, which means that the eggs are fertilized internally, and the eggs develop within the female's body. After hatching, some 25,000 to 40,000 young are retained in the ovaries of the female until the yolk sac of each is absorbed. Then the young fish are born, alive and freeswimming. Mating generally occurs in September or October, and the young are born sometime between April and July. The young are about 7 mm at birth and swim freely in the surface waters until they reach a length of approximately 25 mm, at which time they move into deeper waters over rock and mud bottom.

Growth

Redfish are slow growing and long-lived. Growth varies somewhat from population to population, but generally fish have reached some 15 cm by about the age of four, 25 cm by 10, 32 cm by 20, and 38 cm by the age of 30 years.

Redfish commonly live to be about 40 years old, although one unusual specimen is known to have survived to 84 years. During the first six to seven years, males and females grow at about the same rate, but afterwards the growth of males slows somewhat. Thus, females become larger at any given age than males.

The maximum size of S. marinus, the largest of the redfish, is 50 to 55 cm for males and 65 to 70 cm for females. S. mentella males reach a maximum length of only 40 to 45 cm and the females 45 to 60 cm. Much as the age of a tree is calculated by counting the rings in its trunk, the age of a redfish is determined by counting the rings on the otoliths (small bones in the fish's middle ear).

Redfish reach sexual maturity at eight to 10 years of age on the Grand Banks, but slightly later in the northern part of their range. Thus, on the continental slopes off Labrador the age of maturity lies somewhere between 10 and 12 years of age.

Food

Redfish feed on a combination of small invertebrates, and small fish. They are in turn preyed upon by such species as cod and Greenland halibut (turbot). However, the effect of predation on redfish stocks is not yet well understood.

Fishery

Redfish in the West Atlantic first became commercially important in the Gulf of Maine around 1935. Since then, the fishery has expanded greatly with the discovery of other stocks, such as those in the Gulf of St. Lawrence, the Grand Banks, Hamilton Bank, and on Flemish Cap.

These discoveries were mostly made between 1947 and 1952 from the deck of the research vessel Investigator II that worked out of the Biological Station in St. John's, Newfoundland. The commercial fishery expanded extensively in those years to reach a maximum weight of 389,000 metric tons (t) in 1959. The Canadian landings decreased from 103,000 t in 1975 to 82,000 t in 1979 as a result of quota regulations introduced because of over-fishing in earlier years.

The economic value of redfish to the Canadian industry has increased at a very fast pace over the last few years. The landed value in 1975 was $12 million; in 1979, that value had increased to 15.6 million, even though landings had decreased by more than 20,000 t over the same period.

At first, redfish were caught in large cone-shaped nets, (bottom trawls) dragged along the sea floor during the daytime. Subsequently (with the discovery of off-bottom movement by redfish at night), the commercial fishermen found they could make large catches at night by using a midwater trawl. A midwater trawl is shaped like a bottom trawl but the fisherman is able to adjust the depth at which the trawl is pulled through the water. In recent years, combinations of bottom and midwater trawls have been used so the fishermen can work a full 24 hours, as they do for other species like cod. A few redfish are caught in deepwater gillnets, line trawls and occasionally in deepwater cod traps.

The minimum commercially acceptable size of redfish landed in Canada is approximately 25 cm. Most of the catch is destined to be turned into fillets, skin on or off, which is the major product of shore-based plants, and they are marketed as ocean perch throughout North America. Some redfish are frozen into blocks either round (that is, as they emerged from the sea) or dressed (with the head and entrails removed). Foreign vessels fishing in our waters also produce frozen fillets onboard large factory trawlers, while some countries - the USSR, for example - package small redfish after removing the head and entrails

Management

Redfish are distributed throughout a wide area of Canada's eastern coastal waters. The resource is divided into seven separate stocks, each of which is managed separately. Since 1974, all of these stocks have been regulated by a Total Allowable Catch (TAC) which sets the upper exploitable limit for each stock.

Beginning in 1974 the TAC was set each year and was based upon scientific advice provided by all fishing nations to the International Commission for the Northwest Atlantic Fisheries (ICNAF). Since the establishment of the 200-mile zone in 1977, the TAC is set either by the Canadian Atlantic Fisheries Scientific Organization (CAFSAC) or by the Northwest Atlantic Fisheries Organization (NAFO), the authority depending on whether the stock lies inside or outside Canada's economic zone. In 1983, the various stocks were fished.

The process of gathering scientific data for CAFSAC or NAFO is a careful and painstaking one. Federal research personnel from the Northwest Atlantic Fisheries Centre in St. John's, Newfoundland, and the Marine Fish Division of the Bedford Institute of Oceanography in Dartmouth, Nova Scotia, conduct annual research cruises to study and monitor these stocks. Information concerning age and growth is collected, and estimates of abundance are made. In addition, commercial catches are sampled for size, weight and age in order to keep pace with trends that become apparent within the industry. This information is carefully assessed and decisions are taken so that the fishery may be managed wisely and remain healthy over the long-term.

The seven redfish stocks are in good condition at the moment, except for St. Pierre Bank. However, as more younger redfish become large enough to enter the commercial fishery, the St. Pierre stock is expected to show some recovery after a period of low abundance. The Gulf stock has also been at very low levels until very recently, but in the last two to three years the evidence points to a significant increase in young redfish reaching commercial size than was the case during the latter part of the 1970s.

The Canadian redfish fleet shares the fishery with other foreign nations, although the bulk of the catch is now Canadian. Controls imposed by the Canadian government restrict the catches of redfish by other countries fishing within 200 miles of the coast. There is still room for expansion in the catch by the Canadian fishing fleet if the depressed stocks continue to recover, or if the Canadian apportionment of the total catch is increased.

But in the end, it is market conditions that dictate the size of the fishery.

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Last updated: 2006-06-06

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