NOAA Fisheries announced Wednesday that it will convene a multi-session science workshop to discuss killer whale recovery.
The series of workshop follows completion of preliminary analysis that shows that killer whales depend to a substantial degree on large chinook salmon as a high-calorie food source, and concludes that killer whale productivity is affected by chinook abundance.
“We have not yet made any final conclusions about the significance or use of this new information. We want to conduct our analysis in a transparent and scientifically rigorous manner, and believe we can best accomplish this in a process that engages scientists with a broad range of scientific specialties,” according to a statement this week from the federal agency.
Although the full details have not yet been worked out, Canada’s Department of Fisheries and Oceans will join NOAA Fisheries in the killer whale recovery process.
The Puget Sound chinook salmon are listed under the Endangered Species Act as threatened and the killer whales are listed as endangered. The orcas, known officially as Southern Resident killer whales, are also listed as endangered under Canada's Species at Risk Act.
The agency's preliminary analysis came in preparation of a review of proposed harvest resource management plan for Puget Sound chinook.
The chinook management plan, submitted by the state of Washington and Puget Sound treaty Indian tribes for the fisheries agency's approval under the ESA, would govern Indian and non-Indian sport and commercial chinook harvests through 2014. Because the results of the science review are not yet known, any approval of the proposed harvest plan would likely not be effective beyond 2012.
NOAA Fisheries is obligated under the ESA to determine whether its approval of the fishing plan would jeopardize any listed species or result in the adverse modification or destruction of designated critical habitat of any listed species, including the endangered killer whales.
“If warranted as a result of the scientific review, the management response will be preceded by or include a re-initiation of ESA consultations on salmon fisheries coast-wide,” the statement says of the planned workshop process.
The first of the science workshops will be held this spring. The meetings will share and develop all available scientific information pertinent to the effects fishing has on the whales and ways in which the quality of scientific information can be improved. Results of the workshop will help NOAA Fisheries implement its ESA recovery plan for killer whales.
Envisioned are three workshops in all that will be led by an expert panel comprised of a chief scientist and up to six other scientific professionals not affiliated with NOAA Fisheries or DFO. The panel would include scientists specializing in salmon abundance estimation (modeling), killer whale ecology, and predator/prey relationships. Additional scientific experts will be invited to assist in the review and provide a challenge function (peer review) of scientific information presented at the workshops.
The workshops would be open to observation by the public, but not to public participation.
The panel would produce a report that (1) summarizes the status of the available science pertinent to the effects on SRKWs of reductions in prey abundance resulting from fishing and (2) identifies potential means for reducing data gaps and scientific uncertainties.
“At the conclusion of the scientific workshop process, NMFS and others will be better able to determine what recovery actions are appropriate and, more specifically, whether and under what conditions additional constraints on salmon fishing may be necessary,” Will Stelle, NOAA Fisheries Northwest regional administrator, said in a Jan. 26 letter to constituents.
For purposes of the preliminary analysis, NOAA Fisheries “considered all salmon fisheries that cause mortality of Chinook salmon that would otherwise have been available to Southern Resident killer whales within their known range . This includes fisheries that occur in Southeast Alaska, the inland waters of Washington State and British Columbia (‘inland waters’) and coastal waters off British Columbia, Washington, Oregon and California (‘coastal waters’).
The analysis did not include fisheries that occur in terminal areas, such as the Columbia River, where the chinook are migrating to their spawning grounds and have exited the range of the killer whales. NOAA estimates that Southern Resident killer whale population has only 88 members, and a variable productivity rate. Fisheries are one of several factors identified that may be limiting recovery.
Research has shown that the killer whales have a decided preference for chinook, even when other species are more abundant. In inland waters from May to September, Southern Residents’ diet consists of a high percentage of chinook, with an overall average of 82 percent chinook across the timeframe and monthly proportions as high as greater than 90 percent Chinook (i.e., July: 96 percent and August: 91 percent).
Less is known about the whales’ diet in the Pacific Ocean.
“To date, there are direct observations of two predation events (where the prey was identified to species and stock from genetic analysis of prey remains) when the whales were in coastal waters. Both were identified as Columbia River spring Chinook stocks,” the analysis says.
The preliminary analysis says that “Observational information from the Center for Whale Research suggests that the Southern Resident population may be nutritionally stressed and that malnutrition may have contributed to recent killer whale deaths.”
In addition, “recent demographic modeling demonstrates strong correlations between chinook abundance and resident killer whale survival and birth rates.”
“Considering this information and based on the most conservative, risk averse, scenarios in our analysis, there are times and places where chinook prey available to Southern Resident killer whales is likely insufficient to meet their metabolic needs. There also are chinook fisheries that cause a measurable reduction in prey available at times when the amount of prey available compared to the whales’ needs is already low.”
Supporting documents, including the preliminary analysis, can be found at NOAA Fisheries’ Northwest Region web site: