The link between what happens in the forest, on dry land, and how fish are eating might not be immediately obvious, but scientists have found a clear link between forest conservation and healthy freshwater fish populations. This is because up a lot of what fish eat actually comes from forest biomass (tree leaves and such) that falls in the water and not just from aquatic ecosystems.
"We found fish that had almost 70% of their biomass made from carbon that came from trees and leaves instead of aquatic food chain sources," said Andrew Tanentzap from the University of Cambridge's Department of Plant Sciences. "While plankton raised on algal carbon is more nutritious, organic carbon from trees washed into lakes is a hugely important food source for freshwater fish, bolstering their diet to ensure good size and strength. Where you have more dissolved forest matter you have more bacteria, more bacteria equals more zooplankton. Areas with the most zooplankton had the largest, fattest fish."
Eight areas around Daisy Lake, in the boreal forest of British Columbia in Canada, were studied, and the fish were bigger in areas where the tree cover was healthy than were there were fewer trees. The scientists are confident that their findings will apply in other regions around the world too.
Yet one more reason to fight deforestation and ensure that our ecosystems, both on land and in the water, are protected and healthy.