In July 2018, NOAA Fisheries issued a paper on priority Chinook salmon stocks for Southern Resident killer whales. The following questions and answers provide more information about the priority Chinook salmon stocks.
A: The paper, “Southern Resident killer whale priority Chinook stocks,” describes a model that analyzes how much endangered Southern Resident killer whales likely depend on different West Coast Chinook salmon stocks. At the end of the paper is a list of West Coast Chinook salmon stocks, according to their importance to the Southern Resident killer whales. Several of these stocks are also listed as endangered or threatened under the federal Endangered Species Act (ESA).
One of the key actions in NOAA Fisheries’ Species in the Spotlight Action Plan for Southern Resident killer whales is “target recovery of critical prey.” Understanding the specific stocks of Chinook salmon that Southern Resident killer whales rely on for food will help NOAA Fisheries and our partners target recovery actions to provide the greatest benefit to both native West Coast salmon and steelhead and the Southern Resident killer whales.
A: NOAA Fisheries' West Coast Region and Northwest Fisheries Science Center worked with the Washington Department of Fish and Wildlife to develop the list and model using the best and latest research on Southern Resident killer whales and their prey. That research includes sampling of the whales' prey and scat to understand which types of fish they rely on during different times of the year, as well as analyzing high-resolution aerial photographs that reveal their body weight and condition.
Salmon and whale biologists, managers, and recovery partners reviewed the model and initial list of the priority Chinook salmon stocks and discussed it at a recent workshop sponsored by the National Fish and Wildlife Foundation. The workshop included representatives of the Northwest Indian Fisheries Commission, Columbia River Inter-Tribal Fish Commission, Fisheries and Oceans Canada, Puget Sound Partnership, Long Live the Kings, and the Skagit River System Cooperative. We then shared the list with the working group that is looking for ways to improve the availability of prey for the killer whales as part of the Governor's Task Force for Southern Resident killer whale recovery.
A: NOAA Fisheries and Washington Department of Fish and Wildlife used their most current data and other relevant peer reviewed research to develop a model to identify which Chinook salmon runs are most important to these whales. The model weighs salmon stocks based on how much their ranges overlap with the Southern Resident killer whales. The model also incorporates the latest research identifying which salmon stocks the killer whales eat based on fecal samples and scraps of their prey collected by biologists. The model gives extra weight to salmon runs that support the Southern Resident killer whales when their access to food is limited, such as in winter when aerial photographs show some whales to have poorer body condition.
In summer, the whales feed mainly on Chinook salmon returning to the Fraser River in British Columbia and Puget Sound. In other months the whales expand their diet to include other types of salmon like chum, coho, and steelhead as well as small amounts of bottomfish including halibut and lingcod. Switching to other prey items may be an indicator that there is not enough of their preferred Chinook salmon. The framework and initial priority list were shared with state and tribal co-managers, stakeholders, and non-profit groups to get feedback and make improvements.
A: Southern Resident killer whales range from central California to Southeast Alaska and eat Chinook salmon from many different runs within this area. Southern Resident killer whales eat all year long and need access to a variety of salmon with different run timing and distribution. NOAA Fisheries is committed to recovery of all threatened and endangered West Coast salmon stocks. We jointly created the priority list to help scientists and managers understand where we can focus salmon recovery efforts that will also help Southern Resident killer whales. In addition, there are some Chinook salmon runs that were historically important to the Southern Resident killer whales, but have been significantly reduced or extirpated and are no longer available. While these runs are not reflected in the priority list, they may provide potential for increasing the whales’ prey though future recovery or reintroduction of these populations.
A: The availability of prey is one of three main threats to Southern Resident killer whales. The Southern Resident killer whales are also adversely affected by vessel noise and traffic which can interfere with the whales’ echolocation, making finding their prey harder. When prey is hard to find and they are not eating regularly, it causes the whales to dip into their blubber stores for energy. Often, that fat is contaminated because of pollution in coastal waters. This contamination in their tissues threatens the whales’ long-term health and reproductive success. Given the myriad of threats, we’ve created a comprehensive recovery program for Southern Residents killer whales to address all of these threats.
A: The prioritization will inform recovery actions such as habitat restoration and perhaps production of fish at hatcheries, which are designed to increase the abundance of salmon overall. That will benefit salmon populations, killer whales, and fishing opportunities. Benefits of healthy habitat may well extend to other species of salmon and steelhead that support commercial and recreational fisheries. We assess all fisheries to make sure threatened and endangered salmon are protected, and in doing so also take into account their significance to Southern Resident killer whales.
A: The list can help inform funders in making decisions about a variety of salmon recovery actions and they may prioritize actions that benefit both salmon and Southern Resident killer whales. Connecting salmon recovery actions to recovery of Southern Resident killer whales could increase awareness and bring new partnerships and funding sources to the table. Already, the National Fish and Wildlife Foundation has dedicated more than $2 million in funding toward projects, including habitat restoration, that will benefit Southern Resident killer whales. That money has leveraged more than $2.75 million in matching grants, for a total of nearly $5 million worth of impact on the region, which in turn benefits the local economy.
A: Identifying and implementing actions to improve abundance of the priority stocks requires consideration of various factors including:
These considerations were not factored into the model and are not reflected in the list. However, we will be weighing these and other considerations as we identify and implement actions to benefit both the salmon stocks and Southern Resident killer whales.
A: Adjustments to hatchery production of high priority salmon runs may increase the prey available to the Southern Resident killer whales. However, any increase in hatchery production of Chinook salmon stocks needs to carefully consider the impacts hatchery fish may have on threatened and endangered salmon runs. Hatchery fish can compete with and affect the genetics of natural-origin salmon, which may impact their recovery. Managing recovery of multiple species will require an ecosystem approach that considers food web interactions.
A: NOAA Fisheries is committed to recovery of all threatened and endangered West Coast salmon stocks. Access to quality habitat is a limiting factor for most salmon runs. The priority list can help inform and garner support for salmon habitat projects that benefit both salmon and Southern Resident killer whales.
A: The U.S. Bureau of Reclamation, U.S. Army Corps of Engineers, and Bonneville Power Administration (the Action Agencies) are currently developing an Environmental Impact Statement (EIS) in accordance with the National Environmental Policy Act (NEPA) that will assess and update the approach for long-term Columbia River System operations, maintenance, and configuration, as well as evaluate measures to avoid, offset, or minimize impacts to resources affected by the management of the Columbia River System. Based on scoping, the range of alternatives being considered is broad and will likely include evaluation of potential large-scale changes such as breaching the lower Snake River dams.
NOAA Fisheries is coordinating with the Action Agencies during the NEPA process and ultimately intends to complete ESA Section 7 consultation on the final preferred alternative to assist the Action Agencies in ensuring that their action is not likely to jeopardize the continued existence of ESA-listed species, including Southern Resident killer whales, or result in destruction or adverse modification of critical habitat. During the EIS and ESA Section 7 consultation processes, the federal agencies will consider the effects of operating the lower Snake River dams on prey species currently relied upon by Southern Resident killer whales and any associated measures to avoid, offset, or minimize those effects will be considered during that process.
A: Since Southern Resident killer whales need a variety of Chinook salmon prey throughout their range throughout the year, they can obtain sufficient prey in many ways. Restoring habitat and recovering threatened and endangered Chinook salmon stocks to natural, abundant, and sustainable levels are important long-term goals which may take decades. In the near-term we can take actions that support prey for the current number of killer whales and allow for growth of both salmon and killer whale populations.
A: The growing abundance of California sea lion numbers along the West Coast has raised concern about predation on threatened and endangered salmon and steelhead in the Northwest. Sea lions are protected under the Marine Mammal Protection Act. Salmon is one of their favorite prey when they visit the Northwest, and some of the salmon runs they feed on are protected under the ESA. While balancing the competing laws is challenging, NOAA Fisheries has taken the step of authorizing Oregon, Washington, and Idaho to remove a small number of individually identifiable sea lions near the Columbia River’s Bonneville Dam that have been spotted repeatedly preying on salmon. We are also evaluating another request for similar action in the Willamette River.
A: The model remains a work in progress. It will be updated as we gather additional data and increase our knowledge of where Chinook salmon overlap with the Southern Resident killer whales, what Chinook salmon runs are important to the killer whales’ diet, and where and when the killer whales are food limited. For example, we used a detailed analysis of available data of fall-run Chinook salmon distribution to inform the model. A study to analyze spring-run Chinook salmon movements is now underway. This new information will be included in future runs of the model to improve its accuracy. Another potential next step is to identify stocks that have been more historically important but are not currently reflected in the Southern Resident killer whales’ diet and so may not be reflected on this current list.
Dereka Chargualaf, Fish Biologist with NOAA Fisheries West Coast Region in the California Coastal Office records data during a site visit on the Sacramento River.
Chinook salmon jump in frothy white water. Credit: Laura Mahoney/USFWS
