Stories tagged good friends

Oct
15
2010

Tasty fish & tomatoes
Tasty fish & tomatoesCourtesy Robert and Mihaela Vicol
Fish and tomatoes compete for resources.

Yep, they do, and that resource is water.

The authors of a new report out in this week's issue of the journal Science are reminding folks of that fact.

John Sabo, a biologist at Arizona State University and lead author of the report told NSF News that "Humans may need to make hard decisions about how to allocate water so that we grow the right food, but still leave enough in rivers to sustain fish populations."

His comments stem from the report's findings that human actions--agricultural irrigation, dam construction, and the collective activities that lead to climate change--alter the natural variability of river flows and in the process shorten river food chains, particularly eliminating top predators like many large-bodied fish.
A now dry Colorado River delta branches into the Baja/Sonoran Desert near the Sea of Cortez
A now dry Colorado River delta branches into the Baja/Sonoran Desert near the Sea of CortezCourtesy Pete McBride

"Floods and droughts shorten the food chain, but they do it in different ways," Sabo explained. "Floods simplify the food web by taking out some of the intermediate players so the big fish begin to eat lower on the chain," Sabo said. "With droughts, it's completely different: droughts eliminate the top predator altogether because many fish can't tolerate the low oxygen and high temperatures that result when a stream starts drying out."

Sabo and co-authors--Jacques Finlay, from the University of Minnesota, Theodore Kennedy from the U.S. Geological Survey Southwest Biological Science Center, and David Post from Yale University--suggest that the fate of large-bodied fishes should be more carefully factored into the management of water use, especially as growing human populations and climate change affect water availability.

According to Sabo, "The question becomes: can you have fish and tomatoes on the same table?"

The Role of Discharge Variation in Scaling of Drainage Area and Food Chain Length in Rivers
John L. Sabo, Jacques. C. Finlay, Theodore Kennedy, and David M. Post (14 October 2010)
Science [DOI: 10.1126/science.1196005]

[It's Blog Action Day 2010, and this year's theme is water.]