Vancouver, Washington – June 01, 2007 – Smith-Root, Incorporated (SRI) has developed a non-lethal electric barrier to deter seal and sea lion predation on Pacific Northwest salmon, steelhead and sturgeon.

“This system was tested in British Columbia, Canada, during March and April of 2007. It deterred seals from preying on salmon juveniles in the Puntledge River in Courtenay, B.C., and it prevented seals from moving upstream to favorite feeding areas,” according to Jeff Smith, the company’s CEO. Results showed that marine mammals are extremely sensitive to an underwater electric field, at levels far below those at which fish could be injured. “The levels of direct current (DC) we used in the British Columbia tests are 15-30 orders of magnitude lower than those capable of causing injury to fish, based on published studies in the literature,” added Carl Burger, the company’s senior scientist.

Smith-Root Electric Barrier Demonstrates Potential to Deter Seal Predation on Salmon in British Columbia, Canada

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Vancouver, Washington – June 01, 2007 – Smith-Root, Incorporated (SRI) has developed a non-lethal electric barrier to deter seal and sea lion predation on Pacific Northwest salmon, steelhead and sturgeon.

“This system was tested in British Columbia, Canada, during March and April of 2007. It deterred seals from preying on salmon juveniles in the Puntledge River in Courtenay, B.C., and it prevented seals from moving upstream to favorite feeding areas,” according to Jeff Smith, the company’s CEO. Results showed that marine mammals are extremely sensitive to an underwater electric field, at levels far below those at which fish could be injured. “The levels of direct current (DC) we used in the British Columbia tests are 15-30 orders of magnitude lower than those capable of causing injury to fish, based on published studies in the literature,” added Carl Burger, the company’s senior scientist.

Smith-Root was invited to British Columbia to partner with scientists at the Pacific Salmon Commission (Vancouver, B.C.) and Canada’s Department of Fisheries and Oceans (Nanaimo, B.C.) to test novel technology for marine mammal deterrence. Scientists could not locate any previous studies of the effects of an underwater electric field on pinnipeds. Thus, initial tests were performed on two captive seals at the Vancouver B.C. Aquarium, to examine threshold responses. Under close scrutiny by marine mammal physiologists and veterinarians, each animal (tested independently) stopped at mid-pool and would not go near the electrode end once the field was activated. “One animal was deterred four times and the other was deterred 18 times; they wanted nothing to do with the electrified end,” noted Burger.

Smith-Root also deployed an underwater electrode array in the Puntledge River, Courtenay, B.C., for real-time, in-situ evaluations on seals in the wild. The goal was to determine whether seals could be deterred from a favorite salmon feeding area, and whether upstream movement by seals could be controlled. “In two deterrence trials, 4-5 seals reacted when a very mild electric barrier was turned on, and their response was instantaneous during the last trial when they vacated the area immediately,” stated Burger. An additional evening of testing showed that 10-12 seals could be prevented from moving upstream past the barrier, at a very low level of power. “These results are promising,” added Burger. “They provide the first data on threshold and deterrence responses by marine mammals to underwater electric fields.” Burger summarized the findings as follows:

1. Seals are quite sensitive to a very mild, underwater electric field. (This suggests the potential for a selective barrier application — one that can deter marine mammals without affecting fish.)
2. Seals can be deterred from established fish predation areas in rivers using non-lethal, low-level electric fields. Also, this system can limit upstream movements of marine mammals.
3. This innovative technology can help resource managers recover endangered fishery resources without injuring fish or marine mammals, and can supplement other selective management strategies presently under consideration.
4. The British Columbia results are a scientific first (no previous published accounts of effects of electricity on pinnipeds exist).

What is the next step? Smith-Root has proposed a more comprehensive demonstration project in a Columbia River Basin tributary, where pinniped predation on fish is substantial. The concept for the Columbia River would design, test and evaluate an integrated electric barrier that would employ sonar to turn on the passive array. This system would operate only when the sonar component detected the presence of a marine mammal (based on lung and swimming pattern morphology), while allowing fish migrations to proceed unimpeded. The sonar component could provide side benefits for salmon enumeration in the Columbia River Basin. The vision is to help stakeholders and co-managers resolve controversial resource conflicts where marine mammal predation is complicating salmon recovery efforts.

A report to Congress on marine mammal predation on salmonids prepared by the Department of Commerce in 1999 identified a pressing research need for the development and evaluation of deterrence technologies. The report stated “all potential deterrence options should be considered” (to address increased predation by marine mammal populations following passage of the Marine Mammal Protection Act). It is believed that 4% of the Columbia River’s salmon are lost to marine mammal predation each year (with sturgeon losses also on the rise).

SRI currently operates an electric barrier in the Chicago Shipping Canal (heavily used by boat and barge traffic) that has successfully prevented Asian carp populations from reaching the Great Lakes. Smith-Root has also manufactured electric barriers to control sea lamprey and carp in many other locales. Similar technology would be applied to the marine mammal predation issues in the Columbia. The very brief electric pulses, while capable of causing discomfort, would not be lethal to marine mammals, humans or fish, and would only occur when a seal or sea lion “target” was detected by sonar in the deployment area. The design criteria include considerations for sturgeon migration and the ability to control pulsed currents when sturgeon are detected by the array. Similar to the Chicago Barrier, this system will have no effects on boats or boat traffic.

SRI plans to pursue the development and testing of this concept. “Complex resource conflicts often require multiple approaches and strategies,” Burger stated. “We think we have a viable option to help resource managers address this difficult issue.” Smith-Root is a Vancouver, Washington-based company with over 40 years of experience in the design of innovative conservation tools and electronics for fishery scientists and managers.