Rare catfish discovered in Kotka may represent extinct species in Finland

Last Friday, a catfish discovered in a fisherman’s trap is doing well. Since Saturday, it has been swimming in a quarantine tank at the Maretarium aquarium in Kotka. “It is still very lively and active. It has a small injury on its fin edge, and it is important to monitor its recovery,” said Sari Saukkonen, the managing director of Maretarium.

If the catfish recovers and remains healthy, it will be displayed to the public after a two-week quarantine. “The catfish is opportunistic and has a large mouth. It cannot be placed in the Baltic Sea tank. A suitable habitat for it would be the river tank, which houses rainbow trout and brook char,” Saukkonen explained.

The catfish, caught off the coast of Kotka, is significant as it may belong to a species previously believed to be extinct in Finland. “This is an extremely rare find. It is part of Finland’s native fauna, which we thought was lost,” Saukkonen exclaimed. The catfish measured 63 centimeters in length and weighed 2,290 grams.

Saukkonen doubts that this catfish is the only one remaining in Finland. “It would be unusual for the only catfish in Finland to have been caught in Halonen’s trap. It would be interesting if other fishermen reported any catches,” she remarked.

The fish will not be returned to the wild due to its value as a research specimen at Maretarium. “It’s crucial to obtain a genetic sample and determine if it belongs to an extinct lineage or if it is a descendant of introduced species,” Saukkonen noted.

Teemu Tast, a fisheries biologist from Kotka, mentioned that catfish have not been seen in Finland since the early 1960s. According to Saukkonen, the catfish likely entered Finnish waters during a warm climatic phase. The cooling climate and water pollution have been cited as reasons for its decline. “With the exceptionally long summer we have experienced, could conditions now be more favorable for the catfish?” she pondered, noting that the water quality in the eastern Gulf of Finland has improved over the past 15 years. The importance of this discovery spans various research avenues related to catfish genetics and the environmental factors contributing to their recent appearance in Finnish waters.