When one imagines cannons, images of human cannonballs at circuses or military warfare come to mind. Not a fish being ejected into the air!
Recently, I attended the American Fisheries Society (AFS) Conference in Portland Oregon, where I learned about this incredible new invention known as the “salmon cannon” that helps migratory fish overcome human-made boundaries such as dams.
For centuries, we have dammed rivers for the purpose of water supply, irrigation, flood control, navigation and energy, with over 80,000 dams in North America alone. Despite many of these societal benefits provided by dams, we’ve destroyed the migratory patterns of many fish and prevented adults from reaching critical, spawning habitat.
One of the most critical species hit hard by damming projects is salmon. Pacific salmon spend most of their early life in freshwater before migrating to the ocean as adults. However, once reaching sexual maturity, salmon make the arduous journey back to their freshwater stream of origin to spawn (to release eggs). The migration itself is dangerous, but human-made hazards such as dams hinder these migration patterns, severely reducing stocks to the point that many species of salmon are now deemed endangered.
For decades, researchers and engineers have worked to create alternative ways to help the fish return to their natural spawning grounds (i.e. even flying salmon upstream by helicopter!) However, most of these methods are inefficient and not economically feasible.
Except for the “salmon cannon.”
The “salmon cannon,” more formally known as the WhooshTM Fish Transport System, is a device that uses pressure differentials to pull a fish into the tube, transport it through the tube at speeds up to 22 mph, and then “shoot” it above obstacles such as dams and out on the other side. Even though the fish might look like they are being shot out of a cannon, the fish land safely and easily in water without danger of actually hitting the bottom.
This unique device provides a fish-friendly, safe alternative to transport migratory fish over artificial barriers, rather than what had been previously used: fish ladders. In the past, fish ladders have been used to aid migratory fish in reaching their critical habitat, but fish ladders require large quantities of water to move the fish. Alternatively, the “salmon cannon” is a more efficient and affordable option, providing effective water resource management.
So you might be thinking, how in the world is it even safe or healthy for a fish to be shot out of the cannon? Well, physiological studies on the Whoosh transport system reveal fish being transported in the cannon do not undergo elevated stress levels. Additional external and internal studies on migratory species from trout to salmon show no evidence that fish health has been compromised during cannon transportation. Overall, the “salmon cannon” provides a safe, rapid movement alternative to be used at hatcheries and fish handling facilities, and for overcoming passage obstacles.
Fish enter the “salmon cannon” through either direct handling or voluntary entry, where the fish are attracted to the cannon entry through water flow and various barriers. The fish are only out of the water for a maximum of 5 to 10 seconds depending on the length of the tube, and the tube is kept “misted” so the fish are kept moist during transport.
So how in the world did this invention come about? In a NPR interview, CEO of Whoosh Innovations Vince Brian explained that the “salmon cannon” started with fruit. The Whoosh tube was initially designed to transport fresh fruit, which is very susceptible to bruising and damage at processing facilities. Fruit pickers would drop the apples and pears into a vacuum tube attached to their waist, which would suck up the fruit and safely transport it to the end of the line with no damage to the fruit. With hindered migratory fish passage becoming a larger issue, the inventors decided to try applying their fruit tube to safely transporting fish. The rest is history.
Today, Whoosh works alongside several government groups including the U.S. Geological Survey’s Western Research Center as well as Tribal entities such as the Yakama nations, for research and development of the most effective and safe fish transport systems. Most recently, the Washington State Department of Fish and Wildlife purchased a “salmon cannon” to be used on a tributary of the Columbia River, where wild Chinook salmon will be separated from hatchery-raised salmon. This separation will preserve the DNA of wild salmon and prevent crossbreeding in these unique spawning habitats.
With today’s modern, innovative technology, it’s refreshing to see researchers and developers creating inventions to help reverse anthropogenic effects on wildlife. What will they think of next?
By: Kristin Foss
Mesa, Matthew G., et al. “Physiological responses of adult rainbow trout experimentally released through a unique fish conveyance device.” North American Journal of Fisheries Management 33.6 (2013): 1179-1183.