Scientists have examined this using the example of char
Scientists from the Krasnoyarsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences and Siberian Federal University have discovered how the shading of rivers affects the nutritional value of char, which serves as one of the main sources of beneficial fatty acids.
The researchers noted that char inhabiting rivers without shading from trees along the banks has significantly greater nutritional value, especially in terms of omega-3 polyunsaturated fatty acid content, compared to those in shaded rivers. It was found that char from unshaded water bodies contains twice as many of these fatty acids. Scientists attribute this difference to the peculiarities of the fish’s diet in different water currents.
The study included an analysis of the diet of char in forested rivers such as Tamasule, Kache, and Bazaiha, as well as in the unshaded Mana River. In rivers with forested terrain, a significant portion of the fish’s diet consisted of terrestrial invertebrates (from 30% to 40%), while in unshaded rivers, about 95% of the diet consisted of aquatic organisms.
Char, belonging to the salmon family, is a valuable target for fishing due to its high content of physiologically important polyunsaturated omega-3 fatty acids.