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Fish Tech and Industry Partners Collaborate to Provide Water Recirculation Workshop


Water covers roughly 71% of earth’s surface. Always a valued resource, water has become particularly prized in recent years as the demands on the supply have increased, while the availability has either been maintained, or in many areas decreased. Why so much concern about a substance that covers the majority of the planet? The answer is simple, yet has no simple solution.

Less than 5% of earth’s water is freshwater. And it is freshwater humans require, for hundreds of applications—including drinking, and caring for crops and livestock. Aquaculture is no exception. Yes, the token Alaskan salmon spends most of its life in the salty oceans of the Pacific, but the fish passes its crucial life stages as an egg, fry, and parr in freshwater. As farmers must troubleshoot how to produce more crops with less water, aquaculturists must brainstorm ways to rear more fish with fewer gallons. Earlier this spring, Fish Tech Professor Jim Seeland, Pentair Aquatic Eco-Systems, and Douglas Island Pink and Chum (DIPAC) partnered to host a recirculation workshop in order to better inform Alaskan fish culturists on how recirculation can be used as a technique to use water more efficiently.

Water is relatively abundant in Alaska, but water conservation may still be necessary depending on required densities, flows, available snowpack, and annual rainfall and each hatchery’s requirements and challenges are unique. Recirculation within a hatchery allows the water to be used an infinite number of times, when water quality statistics such as pH and dissolved oxygen are regulated correctly. When hatchery managers want to rear more fish without consuming more water, they turn to recirculation. “It’s becoming tougher to find new water sources, but there is still a desire to produce more,” Seeland explains. Recirculation allows water resources to be stretched. The technique has been used for years, but the technology is always changing. It’s important to keep up. With diminishing water resources, it’s likely that hatcheries will become even more dependent on recirculation.

Seeland saw a void for training in recirculation for fish culturists in the state, and worked with Pentair, a global supplier for recirculation technology, and DIPAC, a corporation that manages two hatcheries in the Juneau region, to develop curriculum for a workshop that would be relevant to Alaskans. He aimed to provide information relevant to all players in the hatchery workforce, from the people feeding the fish, to the overseeing managers. “I made sure that the presenters understood that this is Alaska. We have to make it relevant to the unique issues Alaskan hatcheries face. Solutions need to be practical for small nonprofits, not for large corporations,” Seeland says.

Pentair responded by sending two recirculation engineers and one representative on their dime. “They really stepped up,” Seeland says. DIPAC hosted the workshop, and helped to facilitate the event at its headquarters in Juneau.

Angie Bowers, director of aquaculture at the Sheldon Jackson (SJ) hatchery in Sitka, attended, and helped to run the workshop. “The presenters were awesome,” says Bowers. At the moment, the SJ hatchery only uses recirculation to place a thermal mark on their fish. This involves exposing developing eggs to a decrease in temperature for a scheduled period of time. This causes a ring to appear on their otoliths, a structure within the inner ear that can be used to track age, and in the case of thermal marks, where the fish originated. Recirculation allows the hatchery to adjust the temperature of the water to mark the fish.

There are other ways Bowers would like to see recirculation incorporated into her operation. “How a hatchery could use recirculation is different for every site. Here, we could use recirculation to improve water quality because during certain times of the year the river water carries a large number of suspended solids,” Bowers explains. “This prevents UV sterilization from being effective, allowing parasites, bacteria and viruses through to rearing fish. It can also suffocate developing eggs and alevin in incubation.” Recirculation would make it possible for Bowers and her team to maintain high water quality, and therefore provide a healthy environment for the fish to grow and thrive throughout the year.

The aquaculture industry is always interested in finding new sources of water, and maximizing the ability to do more with less. Recirculation allows just this. By providing workshops, Fish Tech helps to prepare the aquaculture industry for future challenges. Seeland says, “Supporting the industry is one arm of what we do. It’s our job to provide these programs.”


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