Ketal salmon
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Ketal salmon ( Oncorhynchus keta ) |
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| Oncorhynchus keta | ||||||||||||
| ( Walbaum , 1792) |
The chum salmon ( Oncorhynchus keta , Russian Кета / Keta , from which the scientific name is derived; English salmon Chum ; German and dog salmon ) is a species of the Pacific living salmon .
features
The ketal salmon can be up to 100 centimeters long and weigh over 15 kilograms. In the sea, it is silvery blue-green in color and, unlike other Pacific salmon species, has fewer or no points. Large specimens are steel blue on the back. In freshwater, the males have a dark olive-green to black back, reddish-gray sides with vertical green stripes and a dark-gray belly. The females are similarly colored, but with more indistinct markings.
The undivided dorsal fin has 10 to 14, the anal fin 13 to 17 soft fin rays . There are 12 to 15 cage spines on the first gill arches .
distribution
The ketal salmon occurs on the American coast of the Pacific from Alaska to Oregon , to a lesser extent along the California coast to around San Diego , on the Asian coast in the Bering Sea and Sea of Okhotsk south to Japan and Korea . Relatively few Ketal axis swim through the Bering Strait and reach the rivers that flow into the Chukchi Sea , East Siberian Sea and Laptev Sea as far as the Lena and the Beaufort Sea as far as the Mackenzie .
Way of life
The salmon are born in lakes and sometimes fast-flowing rivers on the mainland, but only stay there for a few months. Then they migrate into the sea, which takes up to three years. They stay there for two to four years until they swim back to their native waters, spawn there and then die. The ketal salmon reaches an age of four to seven years. The long migrations between the waters of their birth and the open sea are attributed to their magnetic sense in the case of ketal salmon, sockeye salmon and king salmon .
The female lays 3,000 to 4,500 eggs, up to nine millimeters in size, in a depression that is up to two meters long and dug with its tail at the bottom of the water, which is then covered by the male with a mound of sand several square meters and guarded for a few days. Some salmon spawn in July to August, others migrate up the rivers (e.g. the Amur and its tributaries) up to 2000 kilometers and only spawn in September to December. It takes 60 to 120 days for the fry to hatch.
Young animals feed on zooplankton and insects, adult fish on mollusks , crustaceans and smaller fish.
use
The relatively common ketal salmon has long been the least economically valued species of Pacific salmon, especially on the American side of the Pacific. Since the 1980s, however, its importance grew, especially again in Japan and Russia . The large-grain, red keta caviar is particularly popular .
In Russia and Japan, ketal salmon fishing is prohibited in rivers.
literature
- William N. Eschmeyer, Earl S. Herald: A Field Guide to Pacific Coast Fishes of North America. From the Gulf of Alaska to Baja California (= The Peterson Field Guides Series. Vol. 28). Houghton Mifflin, Boston MA 1983, ISBN 0-395-33188-9 .
Web links
- Ketalachs on Fishbase.org (English)
Individual evidence
- ↑ Kenneth J. Lohmann, Nathan F. Putman and Catherine MF Lohmann: Geomagnetic imprinting: A unifying hypothesis of long-distance natal homing in salmon and sea turtles. In: PNAS . Volume 105, No. 49, 2008, pp. 19096-19101, doi: 10.1073 / pnas.0801859105 .