20 year study finds that sockeye salmon carcasses boosted tree growth by up to 20%.
For over two decades students in the north-west of the USA have been tossing dead fish from a stream on to a river bank as reported in the BBC. The data showed nutrients from carcesses boosted growth in the area’s trees.
Prof Tom Quinn, who supervised the study told the BBC:
“But we always tossed the carcasses on one side of the stream so effectively we were reducing the density of carcasses on one side and increasing the density of carcasses on the other.
“It was something of a natural fertilisation experiment.”
After taking samples from the surrounding area, the scientists discovered that 300 tons of dead salmon, built up over a 20-year period – had postively affected the growth rate of the trees.
“We took cores from live trees that we estimated to be at least 40 years old,” observed Prof Quinn.
“We saw that the effect of the carcass manipulation was to accelerate the growth on that side.
“There was a significant increase in the growth of the trees on the side that we fertilised relative to how well they have been doing prior to the experiment.”