Salmon Steward is the official publication of the Pacific Salmon Foundation in British Columbia, Canada
Issue link: http://digital.canadawide.com/i/300930
S salmon Steward magazine 19 INNOVATIVE TECHNOLOGY A fresh twist on some high-tech tools helps study salmon in the Salish Sea BY ELAYNE SUN C urrent salmon management and recovery efforts are based on freshwater data, but little is known about factors affecting salmon in the near-shore estuary environment before salmon enter the ocean – particularly the impact of growing harbour seal populations. Thanks to the innovation of doctoral student Austen Thomas, a twist on some high-tech equipment will shed new light on this subject. Thomas got involved with the Pacific Salmon Foundation through a research grant for his doctoral work with the UBC Marine Mammal Study. The research was co-funded by the Pacific Salmon Foundation and the Pacific Salmon Endowment Fund. For the study, Thomas developed a new dietary analysis technique using DNA sequencing to identify the species and percentage of salmon in seal waste. "DNA analysis is the best tool that we have available to us for estimating the impact these seals are having on salmon abundance, so that is what is typically done," says Thomas. "However, if we had a method that could literally count fish as they were being consumed, and tell you exactly where that fish originated, and how old it is, that would take us leaps and bounds forward in terms of the quality of the data we have." So Thomas came up with the idea of combining two existing technologies to do exactly that. PIT tags (Passive Integrated Transponders) are a popular technology that places microchips in fish for tracking purposes. "And I knew that handheld remote scanners were already being used for scanning micro-chipped cats and dogs. We just needed a way to make these technologies communicate." With his new design, every time the seal swallows a fish with a PIT tag, the tag number is registered by a scanner mounted on the seal's head. The use of the PIT tag means that fish can be identified by species, origin and age. Once Thomas had built an appropriate model, he worked with Albert Franzheim, an engineer at Wildlife Computers, to integrate his new design into one of their existing seal beanies – used to track the movements of marine animals. "Finding the right antenna for the scanner was one of the biggest challenges, because it dictates the type of PIT tag that can be used. The smaller the PIT tag, the more species we can test for." To date, Wildlife Computers has donated all of the equipment for the testing phase of the project. The Vancouver Aquarium also donated space and resources to help test the technology. Once fully developed, this new seal beanie will detect a tagged salmon while the seal captures it, read the tag number and store it, and once the seal pops its head out of the water, transmit the captured data via satellite back to UBC. The Salish Sea Marine Survival Project is designed around the notion that no one part of the project functions independently. Determining the factors that limit salmon production will require consideration of all factors. The Salish Sea Marine Survival Project groups factors into three categories: environmental conditions, bottom-up effects on salmon and top-down effects on salmon (for details, see centrefold.) "The Strait of Georgia is home to the highest concentration of harbour seals anywhere in the world, and we know they feed on both juvenile and adult salmon. As a predator of salmon, seals could be creating significant top-down limitations on salmon abundance, but the feeding rate of seals on juvenile salmon is not easy to determine," says Dr. Brian Riddell, CEO and president of the Pacific Salmon Foundation. "Austen's new technology will provide the first direct measure of seal predation on a marked [tagged] group of juvenile salmon, particularly during the critical first few weeks in the coastal marine environments." n Austen Thomas testing the ability of the PIT tag to send a signal through his head and register with the scanner using a homemade antenna. restoring salmon in the Salish Sea Click: Salish Sea Marine Survival Infographic