Sakhalin taimen

What it is

This fish is a large member of the salmon family, often called the Japanese huchen or stringfish. It belongs to the genus Parahucho, distinct from other huchens. Adults are primarily meat-eaters, feeding on other fish, while juveniles consume water insects. The species is one of the most ancient types of salmon. Average caught specimens weigh around five kilograms. An unverified report from 1937 claims a length of over two metres.

Where it lives

Its range covers the Northwest Pacific, including Sakhalin Island and the Kuril Islands in Russia. In Japan, it inhabits Hokkaido. On the Russian mainland, it lives in the Primorsky and Khabarovsk regions. Some groups remain in fresh water throughout their lives. Others are anadromous, meaning they migrate between rivers and the sea. They prefer the lower and middle sections of large rivers and lakes.

How it lives

Young fish feed mostly on aquatic insects. Once they exceed thirty centimetres in length, they switch to a diet of other fish. The species takes about eight years to reach sexual maturity. Individuals can live for approximately fourteen years. During this time, they may spawn multiple times. Fossils of its genus date back to the mid-late Miocene period, found in the Agnevo Formation on Sakhalin Island.

Breeding and life cycle

Spawning occurs in the spring. Females lay between two thousand and ten thousand eggs. They deposit these eggs on the sandy or gravelly bottom of rivers. This process allows the next generation to develop in relatively stable riverine environments. The fish do not die after spawning once, unlike some Pacific salmon, and can reproduce several times during their lifespan.

Fish and people

Commercial fisheries catch this fish as bycatch, and poaching remains a problem in Russia. Recreational anglers in Japan prize it as a trophy. Managed fishing sites in Japan breed the species for sport, and raised fish are sold for release. Despite this farming activity, wild populations continue to decline. It is known locally in Japan as itō.

Status and threats

The International Union for Conservation of Nature lists the species as critically endangered. This status has been in place since 2006. Populations have fallen to less than five percent of their historic numbers. Major threats include logging, oil exploration, and conversion of land for agriculture. Urbanization and gas development have also destroyed more than half of its original habitat.

Relatives and look-alikes

It was previously classified under the genus Hucho but molecular evidence places it in Parahucho. It is closely related to other large salmonids but forms its own monotypic genus. Confusion sometimes arises with other huchen species, but genetic studies confirm its distinct lineage.

Questions people ask about Sakhalin taimen

Good reading and sources

• Sakhalin taimen on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data