Harbor seals are protected by the Marine Mammal Protection Act (MMPA). At the same time, they are believed to be a significant predator of threatened Chinook salmon and could be competing with endangered southern resident killer whales. This poses a challenging management trade-off and data describing harbor seal’s historic impact on our food web, which would help guide this trade-off, is limited. By using old bone specimens stored at local museums and the scientific methods, researchers at University of Washington are uncovering more information.
Harbor seals experienced exponential growth in Puget Sound following the implementation of the MMPA, from historic lows of approximately 2,100 in 1972 before leveling off at the current population size of 18,000 (Jeffries et al. 2003). This change in predator abundance has been correlated to declines in forage fish and salmonid survival across the WA coast, which suggests harbor seals pose a threat to the recovery of endangered and vulnerable species in the region, including Chinook salmon and southern resident killer whales (Thomas et al. 2017).
However, this change in predator abundance also coincided with a broad-scale environmental regime shift known as the Pacific Decadal Oscillation in 1977/78, a phenomenon that has also been linked to productivity of fish species in WA, including salmon. Teasing apart these ecological drivers is challenging yet important for management of the Sound as an integrated system.
At the University of Washington, members of the Holtgrieve Ecosystem Ecology Lab, led by gradate student Megan Feddern, are trying to better understand the interactions between harbor seals, their prey and environmental changes to better inform management decisions from an ecosystem-based approach. They aim to do this by:
- Creating a dataset of where harbor seals have been feeding in the coastal WA food web over the past 100 years from museum skull specimens.
- Combine this dataset with other historic datasets of environmental drivers (Pacific Decadal Oscillation, El Niño Southern Oscillation, sea surface temperature) and important harbor seal prey species (herring biomass, salmon populations, Pacific Hake biomass) to identify what ecological components drive harbor seal food web position.
The research is made possible using a recent methodological advancement called compound specific stable isotope analysis of amino acids. Scientists are able to measure the nitrogen isotope ratio (15N/14N) of eleven different amino acids preserved in bone collagen. A small piece of bone (50 mg) is decalcified to access preserved collagen and measure the 15N/14N of the amino acids contained within that collagen and calculate the food web position of the harbor seal that collagen came from. Certain amino acids, called trophic amino acids, show an increase in 15N relative to 14N as an animal feeds higher in the food web. In other words, they’re able to get a better idea whether seals are eating, for instance, more herring or salmon.
During the study, 150 museum harbor seal skull specimens from seals from 1920-2017 have been obtained and the 15N/14N of their collagen has been measured. Scientists now have estimates of harbor seal food web position from the Hood Canal and Puget Sound during that time period, which they are currently comparing to data sets describing different environmental drivers.
Stay tuned for the full results!
This article was created using a flyer from the University of Washington. View it here.
The Washington Sea Grant State Fellowship (formerly the Marc Hershman Marine Policy Fellowship) offers a unique educational opportunity for soon-to-graduate or recently finished graduate students engaged in studies pertaining to ocean and coastal policy issues. This one-year, paid marine policy fellowship matches highly motivated, qualified individuals with host agencies, nonprofits or tribes throughout Washington State. The Washington Sea Grant State Fellowship offers students first-hand experiences in crafting marine and natural resource policies and allows them to share their academic expertise with their host offices.
Applicants must apply through the Washington Sea Grant application process. Fellowship applications due May 10. More information.
Position at Long Live the Kings
Long Live the Kings (LLTK) is a 35-year-old 501(c)3 nonprofit dedicated to the restoring wild salmon and steelhead and supporting sustainable fishing in the Pacific Northwest. The primary role of the fellow will be to help accomplish specific tasks at the interface of science and management related to LLTK’s Salish Sea Marine Survival Project. The project seeks to determine why certain species of juvenile salmon, and steelhead, are dying as they migrate through the combined marine waters of Puget Sound and the Strait of Georgia. The fellow will participate in synthesizing the results and disseminating the findings, tools, and programs established by this project.
Anthony’s and Long Live the Kings began building a partnership in 2014. The restaurant’s founder, Budd Gould and his son Herb (CEO of Anthony’s), found that their vision to preserve the health and well-being of the seafood industry aligned perfectly with Long Live the Kings’ mission to recover wild salmon and steelhead. Budd’s other son, JJ, who is a retired Chief of Wildlife for the Idaho Fish and Game and a certified Wildlife Biologist, was nominated to join the Long Live the Kings’ Board of Directors in 2016. Our partnership has grown ever since.
When we introduced Survive the Sound to the team at Anthony’s, they wanted to help make this innovative campaign a reality. They were excited for opportunity to bring information about salmon recovery to students and the public. We’ve both known that passionate salmon conservationists are often born after enjoying and learning about this precious resource. Anthony’s saw the opportunity to help create this experience for their guest.
“Providing our guests and the rest of the public with accurate information on salmon and our environment is an important step to making better decisions that benefit future generations,” says Budd. “It is an honor and a privilege to be able to partner with an organization like Long Live the Kings that are so dedicated to this very mission.”
Long Live the Kings is thrilled to have a partner like Anthony’s to help bring our mission to a broader audience. The generosity and dedication from companies like Anthony’s allows us to push the boundaries of salmon recovery; to explore new ideas and take on new challenges. Anthony’s is a leader among the growing number of local companies who are setting a high bar for investments in their local environment, empowering us to protect and restore the Pacific Northwest we want to leave for our children.
Salmon are an important part of our life and diet, but we share this resource with many other species. Birds, seals, sea lions, bears, porpoise, whales, and other fish all depend on salmon for a portion of their diet. With salmon and steelhead populations at risk, many people are asking if too many mouths are at the salmon buffet.
In Puget Sound and the Strait of Georgia, Long Live the Kings and our partners are looking at the whole ecosystem to figure out what’s killing young salmon and steelhead on their migration through Puget Sound. In some cases, as few as 10% of the fish survive to reach the Pacific Ocean. Scientists refer to this problem as high juvenile marine mortality.
One aspect of our research considers whether salmon predators are contributing to high rates of juvenile marine mortality, but we’re finding that the story is much more complicated. Interestingly, human harvest of salmon isn’t a significant factor in the case of high juvenile marine mortality because humans aren’t allowed to harvest juvenile salmon and steelhead. That’s not to say that humans aren’t a major factor contributing to these salmon deaths. There is evidence to suggest that human activity and decisions are driving a number of problems: limited prey for young salmon, a lack of estuary habitat, contaminants, and disease.
Humans have even facilitated the increase in marine mammals through the passage of the Marine Mammal Protection Act. This important law has worked well to protect many marine mammals from harassment and death, but people are wondering if it’s worked too well for some species.
Current research suggests harbor seals are eating many salmon. In Puget Sound alone, the harbor seal population has increased three-fold since the 1980s, a time when our salmon survived at much higher rates (Jeffries et al. 2003). While we are still working to better understand their impact on salmon recovery, initial studies suggest seals and sea lions may be consuming two times as many Puget Sound salmon as are caught by humans, with seals being the primary consumer (Chasco et al. 2017).
If a seal boom is contributing to the further decline of already-threatened salmon and steelhead populations in Puget Sound, we need to answer more questions to address the problem. How many seals should there be? What should they be eating? Who’s eating them, or isn’t eating them? Are there factors that make it easier for these predators to hunt salmon? While we don’t have complete answers to these questions, and continued research is absolutely critical to making thoughtful decisions, our work has uncovered some new ideas which give us options to start investing in solutions.
Seals are opportunistic predators, but by analyzing their scat, we know their diets rely heavily on forage fish. Young salmon, steelhead, and forage fish often swim amongst each other in the areas where seals hunt. With declining forage fish populations, some scientists hypothesize that seals may end up eating more salmon and steelhead to compensate. This indicates that rebuilding forage fish populations could help rebalance the food web and take some pressure off of salmon and steelhead.
Transient killer whales are the primary predators for seals and they have been spending more time in the Salish Sea (Puget Sound, Strait or Georgia, and Strait of Juan de Fuca). Estimates suggest that transients eat about 1,090 seals from the Salish Sea each year. Their presence is helping to naturally control seal populations. Reducing noise pollution, contaminants, vessel collisions and preventing oil spills will help ensure that our waters are safer for these whales.
A number of factors may also make salmon and steelhead predators more successful.
- Barriers like the Hood Canal Bridge, Ballard Locks, and dams can slow the progress of migrating fish. Smart predators learn to take advantage of these situations.
- Consolidated releases from hatcheries may be acting like a dinner bell for predators. Studies have shown predators can change their behavior in response to large hatchery releases. Most Puget Sound hatchery Chinook are released during the same two-week window.
- Salmon and steelhead that are affected by contaminants or contract diseases may be slower and easier targets for predators. Just like humans, unhealthy fish have trouble operating at their best, which is very important during their arduous migration.
Long Live the Kings and our partners are working to address these factors, which could give salmon and steelhead a better chance of avoiding predators and making it to the Pacific Ocean.
Our research and approach to recovery looks at the big picture to implement lasting solutions that restore our ecosystem – an ecosystem that will thrive if given the chance. This approach requires thorough planning, considerable funding, and cooperation from others. But, if we’re going to save salmon and steelhead, we’re going to need to restore our ecosystem, and that starts by understanding it better.
Chasco et al. (2017) Estimates of Chinook salmon consumption in Washington State inland waters by four marine mammal predators from 1970 – 2015. DOI: 10.1139/cjfas-2016-0203
Jeffries et al. (2013) Trends and Status of Harbor Seals in Washington State: 1978-1999, Journal or Wildlife Management 67(1):208–219
Image Credit: Vancouver Aquarium. LLTK use “seal-packs” that help us research predator-prey interactions.
The Ray’s team including owners, managers, chefs, servers and hosts all joined together this week to restore critical salmon habitat along the Snoqualmie River.
We teamed up with our non-profit partner Long Live the Kings to volunteer for a day with Stewardship Partners, a local non-profit committed to habitat restoration in the Snoqualmie Valley to help maintain economic viability of farms and forestland while helping landowners restore fish and wildlife habitat.
We worked to remove invasive plant species and install native trees and shrubs to enhance salmon habitat and restore the riverbank on an 80-acre farm in Carnation. The plants will eventually provide shade for the river that will help keep water temperatures low, providing an optimal environment for salmon to thrive.
It was a great day working outside as a team to help keep our local salmon habitats alive and well! Check out some photos from the day below.
Learn more about Stewardship Partners and how to get involved at stewardshippartners.org.
Salmon and steelhead face many obstacles on the road to recovery – sometimes quite literally. In order to better understand how physical obstacles impact the survival of salmonids, it’s important to remember that salmonids depend on intact habitat spanning thousands of miles. When human-made structures block, delay, or reduce even a relatively small part of their habitat, it can significantly impact their whole migration.
Two of the most well-known obstacles are dams and road culverts, which can both restrict access to habitat. Other human-made obstacles can also have big impacts on fish. The Hood Canal Bridge is one local example of an obstacle to salmonid migration.
Steelhead traveling through Hood Canal towards the Pacific Ocean encounter the Hood Canal Bridge which carries State Route 104 across the Canal’s northern outlet, connecting the Olympic and Kitsap Peninsulas. The bridge floats on pontoons that span 83% of the width of Hood Canal and extend 15 feet underwater. The same fish tracking data used to create Survive the Sound show that over half the juvenile steelhead that reach the bridge do not survive to reach the Pacific Ocean. There is strong evidence that the bridge is acting as a migration barrier and contributing to increased. This level of mortality is alarming, and observations indicate that other salmonids, including Chinook and chum salmon, may also be affected by the bridge.
Compared to dams and culverts, it’s less obvious how a floating bridge could affect the survival of migrating fish. Most ask: why don’t they just swim under it? To answer this question, LLTK and our partners are conducting an assessment to pinpoint how steelhead are dying at the bridge. By gathering data on noise and light levels, predator densities, and water currents and comparing those data with the tracking data seen in Survive the Sound, we are able to isolate variables contributing to mortality. Preliminary findings indicate that the bridge creates conditions and habitat that gives a substantial advantage to predators – steelhead that reach the bridge are at high risk of being eaten before they can navigate around or underneath the physical structure.
We have long understood that human-made structures can have unintended consequences on the environment. The trouble is, we keep discovering new ways this is happening. Realizing that this cycle will continue, it’s important for us to constantly research and test innovative solutions.
Luckily, many people are stepping up to the challenge of balancing human and fish habitat. The new Seattle seawall aims to improve salmon survival by mimicking the shallow mudflats that used to exist in that area. By creating an artificial sea floor, glass sidewalk panels, and habitat for plankton (salmon food), the new construction may improve juvenile salmon survival. Projects like these may help decrease the number of obstacles salmon face during their lives while still allowing humans to enjoy the same area.
Photo: Hood Canal Bridge, Hans Daubenberger – Port Gamble S’Klallam Tribe
Sand lance, herring, and surf smelt are called ‘forage fish’ because many larger animals forage (feed) on them, including marine mammals, birds, salmon, and humans. Forage fish are generally small, silvery fish and can be found in large schools throughout Puget Sound. Research monitoring the health of forage fish populations is limited, but the information that is available shows a tragic downward trend for some important populations.
For instance, Cherry Point, an area north of Bellingham, once hosted the largest number of spawning herring in Puget Sound. Cherry Point herring abundance has plummeted 93% since 1973; there are very few Cherry Point herring left. This is bad news for the health of Puget Sound and the prospect of salmon recovery because these small fish hold an important place in our ecosystem.
Recent research from the Salish Sea Marine Survival Project indicates that forage fish are especially important to the success of Chinook salmon in Puget Sound. Not only are they a source of food for Chinook, but they also provide food for birds and marine mammals that might otherwise feed on juvenile salmon. This information suggests that to recover salmon, we have to look at problems more broadly across our ecosystem, especially forage fish health.
Herring need kelp, eelgrass, and other substrates lower in the tidal zone to lay their eggs on and cumulative human development activity is decreasing the prevalence of this habitat. Overwater structures, such as docks, prevent aquatic vegetation from growing by not allowing in enough sunlight. Some structures are also coated in toxic chemicals that kill herring eggs. Pollutants that aren’t associated with docks can also affect forage fish. For instance, PAHs (polycyclic aromatic hydrocarbons) generated primarily during the incomplete combustion of organic materials (e.g. coal, oil, petrol, and wood) can enter marine water directly or through stormwater inputs. Research shows that these pollutants can lead to reduced growth and cardiac defects in larval herring.
Sand lance and surf smelt depend on healthy, natural beaches to provide a place to spawn and protect their eggs until they hatch, but residential and commercial shoreline development has reduced the availability of spawning grounds. For instance, shoreline armoring or bulkheads, designed to protect property from erosion and flooding, can eliminate habitat by restricting access to spawning areas on the beach. They can also prevent natural sediment processes from occurring where erosion from the land replenishes the beach gravel needed for spawning habitat. Despite efforts by many organizations and landowners, we are still struggling to remove or replace bulkheads with engineered ‘natural shorelines.’
Sea level rise and ocean acidification are likely to reduce spawning habitat even further. As sea levels rise around our developed community, tidal habitat and marine vegetation available for spawning will decrease.
Forage fish spawning habitat is currently protected through regulatory documents, which take a “no net loss” approach. This means that shoreline development should not change the ecological function of the shoreline. It’s unclear whether this standard will be enough to protect forage fish habitat given the pressures of rapid development and our changing climate. This standard must be strictly enforced and complemented by restoration activities to be effective.
To improve the health of Puget Sound and salmon runs, an abundance of forage fish is critical and there are a number of complicated issues that threaten the health of these populations. Addressing these problems requires intensive monitoring efforts, stewardship from shoreline owners, strict regulations, and a willingness to try creative ideas. Long Live the Kings is exploring new ways to protect existing spawning habitat and advancing science so that we may uncover even more solutions.
Photo: Pacific Herring, Steve – Flickr
Zooplankton are tiny animals that float freely in the water column. They can move very short distances on their own, but are so small that they are mostly carried around by ocean currents. There are many types of zooplankton in Puget Sound, including copepods, amphipods, crab larvae, and euphausiids (krill) (Zooplankton in Puget Sound ID sheet). These animals are important food for juvenile salmon and forage fish like herring and anchovies.
Because zooplankton comprise the base of the marine food web and support healthy juvenile salmon populations, scientists need to understand what kinds of zooplankton and how many zooplankton are in Puget Sound. To meet this need, Long Live the Kings created a Puget Sound-wide zooplankton monitoring program through the collaboration of local governments, state agencies, and tribes. Researchers sample the zooplankton community twice a month during the juvenile salmon outmigration period (March through October).
Zooplankton are very sensitive to environmental change, so they are excellent indicators of ecosystem health. The metrics developed from data collected by the monitoring program are used to understand changes in the Puget Sound food web that might impact juvenile salmon and to provide guidance towards improved salmon harvest management and Puget Sound stewardship.
The zooplankton monitoring program has been extremely successful, collecting crucial data on environmental health and salmon survival indicators. For example, an environmental index developed from copepod abundance data has been closely linked to salmon survival. This new index is being used to improve forecasting models, which predict how many adult salmon will return to Puget Sound each year.
We need to continue collecting information on the Puget Sound zooplankton community over the long-term. Datasets that span many years allow researchers to understand environmental patterns and track ecosystem responses to changes in many factors like temperature, water chemistry, and pollution. Zooplankton data also show us how much food is available for juvenile salmon and whether that food is healthy for the fish. Continuing to collect Puget Sound zooplankton data is one crucial piece of successful salmon recovery.
Photo: Zooplankton, NOAA
It’s no secret that healthy habitat is critical to healthy salmon and steelhead runs, but restoring habitat is a daunting challenge and expense, often conflicting with human development ambitions. Despite the incredible resilience of salmon, habitat destruction is one of the most significant causes of their population decline. Humans have negatively impacted virtually every part of their vast habitat and we’ve been trying to correct past wrongs for decades.
Since 2005, there have been almost 6,000 salmon and steelhead restoration projects in Washington State. Those projects have worked on over 4,000 acres of estuary habitat, corrected 3,100 passage barriers, and improved over 10,000 acres of riparian land.
We’ve invested almost $982 million in habitat restoration projects since 1999. These efforts have created thousands of construction jobs, poured millions into local economies, and improved the safety and health of many communities. Yet, fewer than half of Washington’s 15 populations of salmon and steelhead listed under the Endangered Species Act are showing signs of improvement. That may not come as a surprise considering that our population has grown 30 percent since 1998 and salmon restoration efforts have only received 16 percent of the estimated funds needed to restore their habitat.
Acknowledging the large task of habitat restoration and restricted funding availability, Long Live the Kings (LLTK) conducts research to understand where best to focus our efforts to maximize effectiveness. The Salish Sea Marine Survival Project, an international research effort led by Long Live the Kings (U.S.) and the Pacific Salmon Foundation (Canada) to investigate poor survival of juvenile salmon and steelhead in the marine environment, has shed light on the importance of estuaries and nearshore habitat for juvenile Chinook salmon.
Estuaries, including the wetlands that surround them, are areas where freshwater meets saltwater. These areas are considered one of the most productive types of ecosystems in the world, providing critical habitat for many species. Nearshore habitat in the saltwater environment refers to the shallow waters near the shoreline, including the beach, intertidal, and subtidal zones. Estuaries and nearshore areas are important for juvenile salmon to rear, feed, migrate, and find shelter from predators.
Salish Sea Marine Survival Project researchers studied Chinook salmon populations in several Puget Sound watersheds. They looked at the scales of juvenile and adult fish to measure their growth and survival in Puget Sound and the Pacific Ocean. These data showed that in watersheds without intact estuaries, smaller fish disappeared from the population. This suggests that healthy estuaries protect small fish and allow them to survive better, which may improve overall adult returns to a watershed.
Estuary and nearshore habitats often fall victim to human development activities such as shoreline armoring, overwater structures (dock, piers, etc.), diking, dredging, and other activities which significantly reduce ecosystem functionality. Human infrastructure is necessary and valuable but we have prioritized easy development over environmental preservation for too long. It is important to remember that humans can improve the efficiency of our infrastructure, while the needs of our ecosystem are relatively unwavering. Adapting to our environment is a challenge that will pay off for generations.
Photo: Nisqually Estuary and Olympics, Eric Hall
LLTK’s Deputy Director, Michael Schmidt, made comments during a science update to the Washington State Departement of Fish and Wildlife Commission regarding the impact of pinnipeds in Puget Sound. This forum was considered a learning opportunity for the Commission and it was not making policy decisions or choosing a course of action. The session was officially described as: “Department staff will brief the Commission on recent analyses examining pinniped consumption of salmonids in Puget Sound and the Outer Coast. In addition, Department staff will brief the Commission regarding management options within the Marine Mammal Protection Act and associated pros and cons.”
Schmidt made the following comments:
Mr. Chairman and the rest of the Commission,
My name is Michael Schmidt. I’m the Deputy Director of Long Live the Kings, a nonprofit devoted to salmon recovery and sustainable fisheries. Since 2014, Long Live the Kings and the Pacific Salmon Foundation of Vancouver, BC have been coordinating the Salish Sea Marine Survival Project. This international effort is to determine why juvenile Chinook, coho and steelhead are dying as they traverse the Salish Sea marine environment. This is a collaborative effort, with 60 state, tribal, federal, private, academic and NGO’s involved, including the Washington Department of Fish and Wildlife, who plays a major role. We reported to the Commission on the steelhead portion of this effort a couple of years ago. To date, over $20M has been invested in 90 ecosystem studies occurring throughout the Salish Sea. This includes some of the seal research you will hear about today.
The science is suggesting harbor seals are playing a substantial role in Chinook mortality in Puget Sound, and we agree it’s an important issue to contend with; however, we ask that you keep in mind the following as you listen today:
We are learning there are likely several factors affecting Chinook survival, and their impacts are likely cumulative. Limited estuary habitat, contaminants, variation in prey, low abundance of herring and pacific sand lance, competition with pink salmon, and hatchery rearing and release strategies all may be playing a role.
When considering how to address the impacts of harbor seals, we ask that you maintain an ecosystem perspective. Past and new research have brought additional hypotheses to the forefront, suggesting that the low abundance of forage fish, migration barriers like the Hood Canal Bridge or Ballard Locks, artificial haulouts, and the consolidation of hatchery release timing across the Salish Sea could be exacerbating seal predation.
We agree we must not wait too long to act, but we ask that you support the Department and their partners in their process to collect and refine the data that will help define a path forward. Ongoing and proposed studies will help clarify the level of impact seals are having, where we should be most concerned, and what options, from an ecosystem perspective, we may have for addressing the issue.
Finally, we ask that, with any action you pursue to increase the number of Chinook returning to Puget Sound, you continue the science, you monitor the effectiveness, and you adjust accordingly based on results. In ecosystem management, all actions are experiments.
The full session can be viewed on TVW.
Featured image from the Encyclopedia of Puget Sound.