Whale poop ups productivity of ocean fisheries
By ANIWednesday, October 13, 2010
WASHINGTON - A new study from Harvard University and University of Vermont has revealed that whale faeces is rich in nutrients, and has a huge positive influence on the productivity of ocean fisheries.
Most whales actually deposit waste that floats at the surface of the ocean, “very liquidy, a flocculent plume,” said University of Vermont whale biologist, Joe Roman.
Whales, they found, carry nutrients such as nitrogen from the depths where they feed back to the surface via their faeces. This functions as an upward biological pump, reversing the assumption of some scientists that whales accelerate the loss of nutrients to the bottom.
Roman and McCarthy found that phytoplankton in the Gulf of Maine in the western North Atlantic has a brake on its productivity when nitrogen is used up in the otherwise productive summer months.
“We think whales form a really important direct influence on the production of plants at the base of this food web,” said McCarthy.
“We found that whales increase primary productivity,” Roman said, allowing more phytoplankton to grow, which then “pushes up the secondary productivity,” he said, of the critters that rely on the plankton. The result - “bigger fisheries and higher abundances throughout regions where whales occur in high densities,” Roman said.
Another implication is that culls and bounty programs would reduce nitrogen and “decrease overall productivity,” Roman and McCarthy noted.
Countries like Japan argue that whales compete with their commercial fisheries.
“Not only is that competition small or non-existent, but actually the whales present can increase nutrients and help fisheries and the health of systems wherever they are found. By restoring populations we have a chance to glimpse how amazingly productive these ecosystems were in the past,” Roman said.
The study is published in the journal Plos ONE. (ANI)
