A Forage Fish's Wheel of Life
The Need for Shoreline Restoration on Vashon Island
Have you ever heard of forage fish?
If you have eaten sardines, anchovies, or herring then you know some forage fish species!
Forage fish species are vital to the Puget Sound, serving as indicators of ecological health for shorelines and oceans, and as important food source for many marine and bird species.
If you have never heard of forage fish, you are not alone! These important species are often left out of the conversation in the world of marine conversation in Puget Sound, which often focuses on iconic species such as Coho and Chinook Salmon, Orca Whales, and Harbor Seals. However, all of these species rely on forage fish for food and energy! Therefore, without the conservation of these fish species and their habitats, the salmon, seals, and orcas will not thrive. And while forage fish serve as major food sources for species in Puget Sound waters, they are also important species found worldwide!
What Are Forage Fish? & What Species of Forage Fish Are in Puget Sound?
Forage fish is a title given to a collection of species of small silver fishes that generally live and travel in large schools together and are pelagic - meaning that these species live in the water column of oceans and coastlines. This means that schools of forage fish will reside in areas both close to or at the waters surface, or their schools can be over 1,000 feet below the surface!
Examples of iconic forage fish species are anchovies, sardines, herring, and mackerel. The fish seen in this photograph are Pacific Herring.
The title "Forage Fish" is given to these species because of their important role as food for predators in global aquatic ecosystems. Forage fish are especially significant species as they are primary consumers - meaning that forage fish consume phytoplankton and zooplankton and transfer that energy to other species in the ecosystem.
This transfer links the energy from aquatic plants and microscopic zooplankton species to the larger predators in oceans and coastlines, meaning forage fish are vital member of their ecological communities! Without them, the link of energy transfer from primary producers (plants/algae) to consumers (larger species/predators) would be disrupted.
In the waters surrounding Vashon-Maury Island, forage fish feed the iconic predators of our region. The many salmon species of the Pacific Northwest rely on forage fish as they grow from juveniles to adults. Seabirds and whales in Puget Sound rely on forage fish for the main bulk of their food!
Without a healthy population of forage fish species, these predators and the Puget Sound food web would experience detrimental impacts such as reduced populations of both the predators that rely on forage fish for food as well as species that the predators may turn to feeding upon in the absence of forage fish. Retaining and supporting forage fish populations supports their own populations & the predators of this region to result in a resilient and stable ecosystem and food web.
Forage fish are considered "Ecological Health Indicators" because of their complex habitat requirements. These species rely on certain environmental conditions and the overall health of shoreline areas to be intact - so when shorelines are unhealthy, not functioning, and are heavily disturbed: forage fish tend to not be present. Therefore, the presence or lack-thereof of forage fish species in Puget Sound can be a signal for the overall health of our shoreline areas.
This picture is of the restored shoreline area known as Lost Lake on Vashon Island and is monitored to record any presence of forage fish in Puget Sound interacting with the shoreline! There are three species of forage fish that are most abundant in our region, keep scrolling to be introduced to them.
Pacific Herring
Pacific herring are the most common forage fish species found in Puget Sound! Their populations are spread throughout the the entire Puget Sound Basin and their larger yellow-tinted eggs can be spotted in huge volumes on vegetation such as eelgrass, red algae, and kelp from the months of January to April in this region.
Herring have a blueish color along their backs but are bright silver on their stomach and sides! These fish can grow to about 10 inches long in Puget Sound and live for around 7-15 years.
Pacific Sand Lance
Pacific sand lance are sword like forage fishes that are a reflective and vibrant silver (this is the reason for their name, as they resemble a Lance sword!). Sand lance lay their circular eggs that stick to sand and other small sediments in the months of November to February in Puget Sound.
Pacific sand lance live to about 7 years and grow to around 8 inches in length. These fish pierce the sand of shorelines at night, burrowing into the sand to protect themselves from predators!
Surf Smelt
Surf Smelt are a forage fish species found all along the West Coast of the United States! In Puget Sound, this species has a variety of spawning times that is thought to be based off of season and weather conditions. In the south-central sound area that Vashon Island is in, surf smelt are thought to release their small, clear eggs on shorelines in a large and variable spawning time from July to April with the concentration of spawning occurring November-March.
So, What is Going on With Forage Fish Habitat?
A diagram showing the various shoreline zones, from subtidal to upland areas.
Many forage fish species rely on healthy shorelines as critical habitat for reproduction. Specifically forage fish spawn in the intertidal and subtidal zones of our shorelines on Vashon Island. The intertidal zone is the area of a shoreline that is underwater at high tide and exposed beach area at low tide, and this is where Pacific sand lance and surf smelt reproduce! These species spawn on the sediments (sand, rocks, cobble, etc.) that are present on the beach. That's right, these are aquatic fish that spawn on land! Pacific herring spawn in the intertidal zone as well as the subtidal zone but they prefer to spawn on marine or terrestrial vegetation such as eelgrass or kelp.
Healthy intertidal habitat provides shade from sunlight by overhanging native trees and shrubs, a diverse composition of sediment sizes present, proper tidal elevation and slope of the beach itself, diversity of bug species on the shoreline, a distinguished wrack line composed of deposited seaweed from wave activity at high tide that provides organic matter and nutrients to the shoreline, among other characteristics.
Natural processes such as erosion and fallen trees are present on these healthy shorelines and support the ideal habitat for forage fish species to spawn.
Forage fish require very small and fine sediments to spawn within, and each species has their own preferred range of ideal sediment sizes. Sediment diameter sizes that measure outside of normal ranges restrict sand lance and surf smelt from spawning on shorelines. A mix of sand and gravel is preferred by both sand lance and surf smelt with sediment of a diameter around 1 to 7 mm being optimal surf smelt habitat and sediment of a diameter around .2-.4 mm is optimal sand lance habitat. These are drastically different sediment sizes, representing the need for diversity of sand, rocks, and cobble present on shorelines.
Shoreline Armoring on Vashon Island
Bulkhead, Seawall, Riprap
Shoreline armoring is the use of artificial infrastructure such as bulkheads, seawalls, or riprap to stabilize shorelines and prevent erosion. Ocean waves naturally erode beaches but this process is interrupted with the installation of shoreline armoring as it is built to decrease erosion of private or public lands. In some cases, bulkheads have been built where they are not needed and where other approaches could work to maintain forage fish habitat and buffer erosion.
Shoreline armoring is the most significant anthropogenic habitat impact on forage fish as the artificial infrastructure disrupts normal sediment transport cycles. Sediment is typically deposited into the intertidal and sub-tidal areas from the natural erosion of inland areas (think bluffs next to a beach), however an armored shoreline traps sediment behind the structural walls, reducing fine sediments over time in nearshore habitats.
Armoring shorelines results in beaches changing size, sediments, and steepness over time through wave activity eroding away the shoreline naturally. Without continuous deposition of sediment on armored areas, either naturally or through the depositing of dredged sands from the ocean, beaches erode away over time. This impact has major implications for forage fish reproduction, as the smaller sediment sizes these species rely on for reproduction disappear, reducing their reproductive habitat. Due to the widespread use of armoring to protect homes and buildings, the impact of this infrastructure is extensive.
Shoreline armoring in the Puget Sound is pervasive. Anywhere on this map that is red is currently armored with some form or artificial infrastructure that limits healthy shorelines from thriving and performing ecological functions. Anywhere on the map that is green is a shoreline with no armoring infrastructure present.
Armoring on Vashon Island is extremely common with much of the shorelines on the island colored in red. Private properties, public parks, and areas near ferry docks are all a part of the areas that are armored. Many of these structures are old and require replacement or removal.
This map is interactive, if there is an area that interests you (maybe a beach you often visit, the area your home is located, etc) we urge you to explore and see which areas are armored and which are not!
But...What Is the Alternative?
While shoreline armoring clearly causes extremely detrimental impacts to the overall health of shorelines and reduces available healthy forage fish spawning habitat, it is important to protect human lives, homes, and recreational areas. In some cases bulkheads are needed. But, in many cases there are alternatives. If we can work together to replace bulkheads in places where feasible alternatives exist, this could significantly improve habitat across the Puget Sound. Presenting, Living Shorelines ! Living shorelines are excellent alternatives to the artificial infrastructure typically used in shoreline armoring. These structures are an example of ecological restoration, or the idea of returning a disturbed natural area back to a condition that reduces disruptive disturbances and increases the ecological value and function of an area.
The concept of Living Shorelines is based on the idea that healthy and generally undisturbed beaches have properties that support slowed erosion and maintenance of the beach area. That shorelines can typically regulate themselves, even in this time of extreme urban developments. Utilizing materials such as sand, rock, oyster shells, and plants, an armored shoreline can quickly turn into a self-regulating natural shoreline that supports increased water quality, reduced erosion, storing carbon from the atmosphere, and finally increasing wildlife habitat - such as forage fish!
Restoration
Shoreline restoration repairs sediment cycles and improves ecological attributes by removing armoring infrastructure and restoring natural conditions. Living Shorelines are an example of these efforts but even the simple removal of armoring infrastructure can lead to a restoration of some ecological processes on our shorelines!
Fortunately, shoreline restoration has been actively ongoing in Puget Sound from as early as 2005 to the present day. These efforts are completed collaboratively across organizations from government entities, nonprofit organizations, and tribal communities working in tandem to restore and monitor Puget Sound shorelines. Removal of shoreline armoring structures creates the most significant impact on shorelines when restoring them but other restoration activities include planting native vegetation in upper shoreline areas, brining in new sediments (sand, rocks, cobble) to the beach area, and the placement of large boulders or logs for fixation on the beach. All are important activities in shoreline restoration. These actions have proven effective in restoring critical ecosystem functions as well as increasing overall biodiversity, habitat for marine species and insects, and resiliency to disturbances such as pollution, urban development, and rising tides.
Below is an example of one of the 6 restored shorelines monitored by Vashon Nature Center on Vashon Island. These sites are now King County Natural Areas and were purchased by King County from willing landowners with the purpose of restoring these important shoreline sites. The site below, Forest Glen, is on the southeastern side of the island. Use the slider to look at the site prior to restoration on the left side, and after restoration of the site on the right!
Forest Glen before and after restoration project completed in 2018
Below is another restored shoreline area on Vashon Island known as Piner Point, this area is on the southeast shoreline of Maury Island. Once again, the left side is the site prior to restoration of the shoreline, and the right side is after the shoreline has been restored!
Piner Point before and after restoration project completed in 2018
Maybe you notice differences in the slope or gradient from the upper area with plants to the sand and eventually water, or maybe differences in the size of the beach area among other differences. Restoration can drastically shift the vegetation growth and abundance in the upper area of the shoreline, the diversity of sediment sizes on the beach itself, and the angle of the gradient connecting the upper shoreline to water. All of these changes are theoretically important to forage fish, and Vashon Nature Center aims to find out exactly how restoration of shoreline areas has impacted these fish populations around the island.
Community Science!
We are grateful to all the community volunteers of all ages who have helped us with forage fish surveys over the years. We could not have covered as many beaches without your help!
Community science is an opportunity for research methods such as field work, data collection, and analysis to be completed with the support and collaboration of volunteers, students, and interns across local communities. This form of research connects individuals to the natural world around them in a unique way, encouraging a sense of wonder and education while also collecting a greater sum of data across larger geographical areas than scientists can do alone. Without the efforts of community members and the Vashon Nature Center team, the information you see presented here today would not exist!
Vashon Nature Center has been monitoring shorelines on the island prior to and after restoration since 2016 to understand forage fish species use of these areas. These efforts are in collaboration with local community members, volunteers, students, and research scientists among others in a form of community engaged research. Anyone with an interest in conducting surveys such as shoreline assessments, microscope lab work, beach seine surveys, and snorkeling surveys is welcome to join in and collect data on the state of Vashon Island shorelines and forage fish presence around the island. Please visit our events page on our website to view opportunities.
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What Do We Know So Far?
From the surveys and date collected with the help of many community members and volunteers, Vashon Nature Center has accumulated a large number of samples which we analyzed to get a better understanding of how forage fish species are interacting with Vashon Island shorelines and where the gaps in our data currently are.
Below is a dashboard that contains statistics and graphs that represent of 7 years of VNC surveys, from 2016-2023.
Forage fish overall visuals
Forage fish site visuals - navigating to the different site locations on the interactive map will show you the before and after pictures of the restoration areas and provide site specific information about each location.
From our surveys, we observed the highest number of eggs in restored areas, with surf smelt eggs being the most abundant species. In addition, many of the restored sites had an increase in the diversity of eggs found as compared to pre-restoration, armored and natural sites indicating that restoration may increase habitat for more types of spawning to occur. Interestingly, Piner Point and Corbin Beach were the only sites to have sand lance eggs. These two sites are on opposite ends of Vashon-Maury Island which leads us to wonder what habitat features might make these locations particularly favorable for sand lance?
Since 2019, we’ve observed an overall decline in forage fish eggs. However, it is important to note that not all sites were consistently surveyed over the past 7 years, and there has been considerable variation from year to year at certain sites. This could indicate a broader decline in populations on a regional or island wide scale or it could be an artifact of less survey effort in recent years. We will be keeping an eye on this as we ramp up survey efforts across the next few years.
There is still much to learn, which is why it’s essential to continue collecting data over a longer time scale to accurately assess the health of our local populations and the effectiveness of shoreline restoration. This ongoing effort will help fill gaps in our current dataset and allow us to better identify trends in over time.
How Do We Move Forward To Support Forage Fish, Shorelines, & Our Community?
Forage fish are amazing keystone species in the Salish Sea that feed and sustain the vibrant biodiversity present across the region. When their habitat is under attack from overuse and degradation of shorelines, their ability to reproduce and subsist is depressed. The benefit of even understanding those concepts and how we as a community can either harm or support these habitat areas and species is immense. So, how do we as a community, researchers, and nature lovers more forward?
"Our mission is to create transformative nature experiences through community science, research and education for the benefit of our island home and the entire Salish Sea."
Our work is centered in the belief that when we work together as a community, we achieve transformative experiences with and for the nature around us. Forage fish species and their habitat quality are as much a community and human issue as homes being protected from shoreline erosion - and it just so happens they are deeply connected. It is important to have both healthy, safe homes and healthy fish habitats.
If you are a beachfront owner or an island resident interested in learning more about shore friendly techniques and living shorelines, please see the links on the learn more page. There are county programs to help you assess whether alternatives to bulkheads are possible for your property.
We will continue to involve our community (that means you and anyone, anywhere reading this) in the surveys, research, and education around forage fish as we are all learning together. We are dedicated to our community, the forage fish & the health of our shorelines. In order for this program to run it is contingent on funding & resource availability as well as our community actively engaging in our programs. If you work in community with Vashon Nature Center, either through the donation of your time and presence at our community science surveys or through a direct financial donation - we are so grateful for you and excited to continue to create deep connections together to the nature around us through research and community.
If you would like to get involved with our community science programs or if you would like to donate to Vashon Nature Center, please follow the links below.
