MOSCOW, November 7. /TASS/. Biologists from the Siberian Federal University (SFU) and several RAS institutions have analyzed the nutritional value of seven commercially harvested types of whitefish (cisco species) inhabiting the rivers and lakes of Russia’s northern regions. The most nutritious fish species are cisco from Lake Sobachie in Taymyr and omul from Yenisey.

The nutritional value of these species surpasses all freshwater species studied globally as demonstrated by comparisons to previously published data of other studies. The new study was published in the journal Lipids.

"In general, the most studied species have been shown to have high nutritional value for humans but unfavorable ecological conditions can substantially diminish this (nutritional) value," the authors of the study noted.

The researchers took the fish samples from their natural habitat during periods when commercial fishing is permitted. They studied seven species of freshwater fish: omul (Coregonus autumnalis), Siberian cisco (Coregonus sardinella), peled (Coregonus peled) or northern whitefish, tugun (Coregonus tugun), broad whitefish (Coregonus nasus), cisco (Coregonus lavaretus), and vendace (Coregonus albula). All these fish belong to the cisco species.

To start with, the scientists focused on the content of omega-3-polyunsaturated fatty acids (PUFA), one of the essential components of a healthy human diet. The largest content of healthy PUFA was found in omul (about 17.6 mg per 1 g of biomass) and cisco (about 16.6 mg/1 g of biomass). These numbers surpass analogous ones of all freshwater fish studied globally and approach those of sea fish.

As all studied species are genetically very close, the differences in PUFA content could be attributed to ecological influences according to scientists’ opinion. In particular, the peculiarities of migration, nutrition, and the state of water ecosystems, in which the species inhabit can change its nutritional value. The fact is that the fish get omega-3 acids by consuming maxillopods and other smaller dwellers of water ponds, which in turn consume algae synthetizing these acids. In this manner, the nutritional value of fish that land on a person’s dinner plate is influenced by the state of the whole ecosystem.