Salmon have serious swimming skills—some travel thousands of miles to return to their original homes to breed. But even though they can jump as high as 12 feet in the air, they can't manage to get over massive concrete dams that we have built to block their journeys back to their homes. Now one new idea could give them a boost. The plan involves whisking the fish through a long vacuum tube at speeds up to 22 mph and then shooting them out the other end like a cannon.
Though the technology is fast, it's also gentle on the fish; the long flexible tubes were actually first developed to automatically move delicate fruit without bruising it. When the engineers that created the device happened to be visiting an orchard in California and saw barren fields that water had been redirected from to help fish travel upstream, they started to wonder if their technology could help.
"I think everybody had really tried to solve the problem with concrete and water—saying the fish has to be in water, and how are we going to help them up," says Vincent Bryan III, CEO of Whooshh, the company producing the new fish cannons.
Many dams have so-called fish ladders, a series of concrete steps with pools that try to guide migratory fish to the top. But the fish ladders, which can cost millions of dollars and take years to build, don't always work—one recent study of some Atlantic salmon found that only 3% actually made it over the dam.
"We were coming from a different discipline," Bryan explains. "We don't work with concrete, and it seemed to us from simple observation that fish leave the water when they run into danger or when they run into a barrier." The designers learned that it would be safe for fish to be out of the water for a few seconds, and after successfully testing the tubes on some unsuspecting tilapia, spent the last few years modifying their technology for fish.
The fish are attracted to the flow of water in the device, swim inside, and then get catapulted out the other end. Research has shown that fish seem to be able to learn from each other, so when one salmon makes it through, others will quickly follow.
Fish can also be placed inside by hand in fish rescue operations—currently happening in drought-stricken places like California—where fish biologists currently have to struggle to get slippery, strong fish safely into trucks for transportation. The company is making mobile versions of their tech along with devices that would be more permanently attached to dams.
Of course, another way to solve the fish transportation problem is to take down dams. But while Whoosh agrees that some dams may be unnecessary, they argue that most play an important role as a renewable energy source that can complement intermittent solar and wind power.
"I think from a practical perspective we can't afford to take down the 80,000 dams that exist in the United States," says Bryan. "If we did, we would flood ourselves out and we would lose power. Really, things are going in the opposite direction. In the last year, the federal government reemphasized hydropower to double hydropower production by the year 2030."
Right now, only about 2,000 dams have hydropower. As the government starts to add power plants to some of the other 78,000, it will add requirements for fish passage.
"If they do that, then they allow the fish to get up into these areas where they haven't been able to get to for years, and won't be able to short of taking down the dam," says Bryan. "From a very practical standpoint, we look at the situation and we say is there a solution here that can benefit all parties? Fish have really slowed hydropower growth in the United States over the last number of years, but it's the cleanest energy that we could have. Hopefully we can help make it happen."
After slowly working through government approval processes and independent testing for safety, the technology is beginning to be tested in pilot projects. At the Washougal River in Southern Washington, pictured above, the technology is ready and waiting for a run of salmon expected in the next few days.