Many species of fish are threatened by changes in environment, habitat or overfishing that are threatening the existence. Kokanee salmon and sockeye salmon are two types of such fish and experts are applying conservation efforts to help save the population.
Kokanee and sockeye salmon are two forms of the same species — and that species has been deemed endangered by the U.S. Fish & Wildlife Service in 2005. The species rank third in population in the seven species of Pacific salmon, behind the pink salmon and the chum salmon.
The Differences Between Kokanee and Sockeye
Both forms are of the species oncorhynchus nerka.
The primary difference between the two is that sockeye salmon evolve into kokanee salmon. Some experts described kokanee as a land-locked version of the sockeye because the sockeye spawns in lakes and migrates into waters of the Pacific Ocean while do not migrate and spend all their lives in the freshwater lakes.
The sockeye can grow to nearly 3 feet and weigh an average of 8 pounds; the kokanee are smaller, growing up to 2 feet and weighing about 4 pounds.
Spawning and Habitat
The name “sockeye is thought to be a variation of the Native American word “sukkai.” The sockeye can be found in waters in western Alaska and in waters near Siberia south to Japan. Adult sockeye salmon migrate to freshwater lakes only to mate. They die after they spawn, leaving the juveniles to migrate back to Pacific Ocean waters after one to three years in the lakes.
An observer can spot a spawning sockeye by the unique way it looks. The fish’s body will turn bright red but the head is green. This is a change from the standard bluish black color with silver stripes the adult sockeye sports in the ocean. During the spawning phase, the sockeye have been nicknamed the “red” salmon in Alaska while they are commonly “bluebacks” during their normal migratory phase.
The kokanee siblings of the sockeye are essentially the fish that do not migrate back out to the ocean after spawning. Experts have observed the two forms of fish interacting.
The kokanee also sport reddish coloring and a green head. The name “kokanee” comes from a Native American word for “red fish.” But for the sake of identification, only salmon living in the ocean as referred to as sockeye.
What’s Killing Them
There is reportedly no one thing that is threatening to send sockeye and kokanee salmon into extinction. A combination of factors caused by humans and by nature are to blame. Some of those threats include:
● Changes in temperature caused by modification in the natural flow of water
● Introduction of non-native species to Pacific waters, causing an increase of predators
● Altered habitats from floods and droughts
● Altering of the environment for hydropower purposes
Researchers are trying to re-introduce sockeye and kokanee salmon back into the waters through hatcheries, removing dams that hamper migration and improving and developing habitats for the salmon to thrive.