Brown Trout (GIZ)

Reintroduction of the Brown Trout in Armenia’s Rivers Studied by AUA Acopian Center for the Environment 

bigtroutOverfishing in the 1990s has led to a collapse of Brown Trout (Salmo trutta morpha fario) stocks throughout Armenia. This species, once available abundantly in all of Armenia’s provinces, is currently found in fewer than 20% of surveyed rivers. To determine the suitability for its reintroduction, the AUA Acopian Center for the Environment with support from GIZ, the German Organization for International Cooperation, has conducted an extensive survey of physical and chemical properties of 22 rivers and streams in 7 provinces of Armenia. 

“The results of the survey are promising,” says Dr. Karen Aghababyan, chief scientist of the AUA Acopian Center and the study’s principal investigator. “Most rivers studied are suitable for reintroduction of the species. Their oxygen and pH levels were within the range preferred by the Brown Trout, and most sites had appropriate levels of ammonia and carbon dioxide, as well as enough benthic invertebrates to serve as food for the reintroduced fish,” explains Dr. Aghababyan. 

In addition to scouting river sites, the AUA Acopian Center researchers found an appropriate brood stock with which to populate the rivers in question. To this end, the Center has collaborated with a fish farm that had Brown Trout captured wild in the Arpa River in 2009. This trout, which has not interbred with other fish species and has not gone through artificial selection, caries all the genes of the wild population and is suitable for introduction into the native stocks. 

For many decades, the Brown Trout has been a staple fish in diets worldwide. In most parts of the world, Brown Trout is interbred with local populations, resulting in fish that is genetically different from their ancestors. Very few places on Earth are home to genetically pure Brown Trout. Armenia is one of these places, its mountainous rivers providing protection from interbreeding with non-indigenous species. 

A successful reintroduction of a fish species needs more than adequate water conditions and pure breed. “We also need to ensure that the site is protected from poachers. Communities close to these fish populations have to have economic incentive to protect them. Local stewardship of the fish stock has to be worked into the reintroduction,” says Dr. Aghababyan.