Saffron Cod fish identification, its habitats, characteristics, fishing methods.
The saffron cod is a commercially harvested fish widely distributed in North Pacific from the Yellow Sea, North Korea, in the southwest to Sitka, Alaska in the southeast. They found beyond the Bering Strait in the Chukchi Sea, Cape Lisburne, and east to Dease Strait (south coast of Victoria Island). The saffron cod normally occurs in shallow coastal waters at less than 60 m depth but may also be found at depths up to 200 m. It is dark grey-green to brown, with spots on its sides and pale towards the belly. It is very sensitive to temperature during reproduction period: spawning takes place under ice at a temperature of 1.6-1.8 °C below zero. It may grow to 60 cm and weigh up to 1.3 kg, age of life – up to 15 years.
Saffron cod, Eleginus gracilis, also known as Far Eastern navaga, Wachna cod, Pacific saffron cod, Morue boréale in France, Bacalao boreal in Spanish, Komai in Japanese, Навага Дальневосточная or Вахня in Russian, is a fish of the cod family Gadidae, closely related to the true cods (genus Gadus). It is widespread in the seas of the North Pacific Ocean from the Chukchi Sea on both sides of the Bering Strait to the Yellow Sea, North Korea in the West and to the Sitka (Gulf of Alaska) of the American coast, occurs almost everywhere in Kamchatka coastal waters, from Penzhin Bay (north-west coast) to the western part of the coast of the Bering and Okhotsk seas, and Japanese seas. This species inhabits the Western Arctic from Cambridge Bay to the Beaufort Sea.
This species is distinguished from other cods by its upper projecting jaw, a shortened caudal fin, and a chin barbel that is the same length as the diameter of its eye. Its dorsal fin is split into three sections, the first of which is the shortest. The second and third are pyramidal in shape and approximately equal in size. The anal fin is separated into two sections, both of which are pyramidal and equal in size. The pelvic fins are reduced and located below the head, while streamlined pectoral fins are located behind the gill slit. Lateral line curved in front, ending under the second dorsal fin; head with no lateral line pores. Expanded parapophyses are swollen and hollow.
The first 4 vertebrae without transverse cross-section processes, the following four are short and without swellings. Starting on about 9th or 10th vertebral the transverse processes are elongated and end with small bulges, which developed considerably weaker than that of Navaga, Eleginus nawaga. Front swim bladder appendages slightly curved. Second pelvic ray is produced; caudal truncate or slightly emarginate. The length is usually 25-35 cm, rarely up to 50 cm, max length 63cm, and a weight of 1 kg.
Distinguished by a lower jaw that is shorter than the upper, a chin barbel that is no longer than half the eye diameter, and a space between the second and third dorsal fins that is equal to or longer than the eye diameter. Bulbous snout. Upper jaw protruding beyond the lower jaw. Truncate caudal fin. Back and upper sides brown to gray-green with mottling. More or less pronounced yellow wash on body and pectoral fins. Juveniles (to 6-7 cm) have large dark blotches on sides.
The back is dark olive, the sides above paler, sometimes with silvery-violet shading yellowish below, often mottled with indistinct darker blotches. The belly is yellow to a silvery-white. The back and sides indistinct dark spots, which are more pronounced in winter. Fins dusky, the edges of the caudal and dorsal fins bordered with a white stripe.
44-59 (11-15, 15-23, 18-21) dorsal soft rays
39-47 (20-24, 19-23) anal soft rays
57 – 64 Vertebrae
14-25 Gill rakers
Max. Length 60 cm
Max. Weigh up to 1.3 kg
Max age of life – up to 15 years
Saffron cod prefers the upper levels of the ocean and occurs in shallow coastal waters at depth less than 60 m in the Arctic and western Pacific, and at depth less than 50 m in the northeastern Bering Sea and western Alaska, Norton Sound, on the continental shelf edge at 200 m depth off northern Japan. The Saffron cod also enters brackish and even fresh waters in a mouth of the rivers and into lakes, may go quite far up rivers and streams, but remaining within regions of tidal influence. The most numerous groups are met near firths of big rivers, sometimes the fish goes up into the lower courses of the rivers. It constantly keeps in the coastal zone, approaching to the coast in the winter for spawning and a little migrating in the summer for fattening in the exposure of the water off the coast at a depth of 30-60 m.
The juveniles stay in shallow water throughout the year, while adults undertake limited seasonal migrations related to spawning, feeding and water temperature changes. In early winter, the fish move inshore from the coast or estuaries into adjacent sand-pebble areas for spawning. After spawning, they return for feeding to silty bottoms or estuarine areas. They spend the winter under the ice cover and in early spring, when the water warms up, they move offshore to the cold and highly saline waters of the open sea. However, the southern Kuril population spends the autumn-winter period in the open sea at depths of 100 to 200 m because the absence of temperature conditions necessary for spawning in August-October in the coastal shallow zone compels the fish to migrate into colder waters.
Juveniles and adults are opportunistic epibenthic feeders, feed on fish, small crustaceans, mysids, decapods, amphipods, polychaetes; juveniles feed on fish and small benthic crustaceans. Feeding starts in summer and goes on until the winter spawning. It is then reduced and resumes in mid-winter after reproduction.
Saffron cod makes annually an inshore migration into shallow waters under the coastal sea ice in winter. They begin to mature during their second to third year of life. Saffron cod spawn once a year, 5 to 7 times in its life, and sometimes even 9-10 times for those fish that live up to l0-14 years. Spawning occurs during December - March in coastal zones of bays, gulfs and inlets, over sand or gravel bottoms and in strong tidal currents, in low from -1.6 up-to -1.8 °C bottom temperature, at depths of 2-10 m, with the exception of the Gulf of Terpenie stock that spawns at depths of 25-32 m. Saffron cod is very sensitive to temperature during reproduction period.
Fecundity is 5,000-680,000 eggs laid per female but depends on body length, weight, and age and by region. A two year-old female (17 cm length) has 4 900 eggs while a 9 year-old (47 cm length) can lay a maximum of 680 000 eggs. 20-35 cm females can have from 29 000 to 124 000 eggs. Fecundity increases from west to east in the European Arctic and from north to south in western Pacific waters. After spawning, saffron cod disseminates in the coastal waters, but doesn’t go far into the sea and occurs in the disseminated state; it is unlikely to form colonies
Eggs are benthonic, adhesive, slightly sticking, spawned on sand-gravel substrate. Larvae are pelagic mature over the winter and hatch out in early spring (April-May) in the Arctic or North of the western Pacific, and somewhat later (during warming) in waters farther south, such as the Sea of Japan. Hatching larvae conduct a planktonic lifestyle; young saffron cod often associate themselves under a bell of jellyfish (Cyanea ferruginea) for two to three months. They do this likely for protection. Once they are old enough to feed on their own, young saffron cod consume a variety of prey, including crustaceans, worms, and fish. Juveniles and adults are opportunistic epibenthic feeders; juveniles feed on fish, mysids, decapods, and amphipods. The growth rate is relatively slow and differs by sex and depends on the amount of forage available. Highest growth rates occur in fish that mature earlier.
Saffron cod are taken commercially throughout the winter season in many areas of the western North Pacific: Peter the Great Bay, Sakhalin region, and Sea of Okhotsk and Kamchatka waters. The country with the largest catch is Russia. It is used for human consumption in the Russian Federation and Japan, fresh or frozen. Fishing is carried out during late autumn and winter by the USSR and, in Norton Sound, by Alaskan fishermen. Fishing gear used are not highly mechanized and include hook and line, float bottom gear, beach and danish seines, gill nets, hoop-nets, fyke nets, and trawls. The fish tries to strike, giving the attacker to the ground, which is passed on the nod as the bite, and the angler can fish for catching stomach, gills, etc.
Cod meat is white in color, is moist and lean, medium- to firm-textured, and delicately flavorful with a mild taste. Tender, thick fillets with large flakes that "gape" (separate) when cooked. It is a good source of low fat protein, phosphorus, niacin, and vitamin B12 with a mild flavor and a dense, flaky white flesh. Cod livers are processed to make cod liver oil, an important source of vitamin A, vitamin D, vitamin E and omega-3 fatty acids (EPA and DHA).
Cod is excellent for poaching, broiling, baking, braising, and frying. A popular main ingredient in chowders, which are creamy and binding enough to support the big flakes of meat that fall apart when cooked. Whole cod are often stuffed and baked. Heads and bones make fine soup stock.