STEM for Future Generations

Jessica teaching about salmon

Science, Technology, Engineering, and Mathematics (STEM) schools in our area and across the country are working to improve the way our students learn in these subject areas. These STEM-focused schools offer a more hands-on approach to teaching, from using objects students can physically manipulate to working with resources and companies in the area to bring in experts to teach the students more about these fields.

This is why Jessica Blanchette, a marine biologist at Hart Crowser, volunteered her time to educate the 4th graders of Odyssey Elementary on the life cycle of salmon, a crucial element of the ecological community of the Pacific Northwest.

Using multiple instructional strategies, including hands-on activities and colorful presentation materials, Jessica captivated Mukilteo School District students with her knowledge of fry, parr, and smolt—the salmon life cycle. Students had many questions and Jessica had plenty of answers!

Jessica led a thoughtful discussion about the human relationship with salmon, our impacts on them, and ways in which we can promote a successful co-existence. There was excitement in the classroom as the lesson wrapped up: not only because of the activities and new knowledge, but also because the students were beginning to see that one day they, too, can be scientists.

When scientists like Jessica share their time to promote STEM, it has a positive and lasting impact in the community. Hopefully, with more endeavors such as this, local scientists will make a positive difference in our world and for future generations.

Salmon Life Cycle

Mussels Reveal Impact of Puget Sound Stormwater

Bay Mussels

Native mussels (Mytilus trossulus) like these were used to evaluate the degree of contamination in Puget Sound nearshore habitats. Photo: Brewbooks

The mission of the Washington Department of Fish and Wildlife (WDFW) is to preserve, protect and perpetuate fish, wildlife and ecosystems while providing sustainable fish and wildlife recreational and commercial opportunities. An important initiative is evaluating the impacts to nearshore aquatic areas from stormwater discharges. Mussels sieve the water as they feed, and their tissues absorb and retain chemicals and pathogens, so the WDFW led a study using mussels as an indicator organism. They got help from so many organizations and volunteers, the list fills nearly an entire page. It includes the Snohomish County Marine Resources Council (Mike Ehlebracht, Hart Crowser geochemist, volunteers for the MRC), the Washington State Department of Ecology, other governmental agencies, native American tribes, and various non-governmental organizations. The work was funded under the new Stormwater Action Monitoring (SAM) program that is paid for by municipal stormwater permit holders.

How Was the Study Done?

As part of this study, the WDFW and volunteers placed “clean” caged mussels at over seventy locations across Puget Sound, including highly industrial areas (such as Smith Cove and Salmon Bay), urban areas like the Edmonds waterfront, and rural areas (such as the San Juan Islands). They left the caged mussels in the water for several months, then retrieved them, often in the dark, in cold and blustery weather. They tested them for stormwater-related contaminants including PAHs (produced by burning coal, fossil fuels, wood, and garbage), PCBs (used in electrical apparatuses, surface coatings, and paints; banned in the US in 1979), metals, PBDEs (used in flame retardants), DDTs (insecticides; banned in the US since 1972), and others.

And the Results…

The study showed that stormwater discharges continue to impact the nearshore aquatic environment, particularly in industrial and highly urbanized (paved) areas. PAHs and PCBs were the most ubiquitous, problematic chemicals detected in the mussels, with some of the highest concentrations found in Elliott Bay (particularly Smith Cove).

Puget Sound is a large, complex, and diverse estuary. This data will be critical in determining best management practices and providing recommendations for environmental remediation. The next round of sampling will occur this fall, with updated data available in another year or two.

Download a copy of the Stormwater Action Monitoring 2015/16 Mussel Monitoring Survey: Final Report.

Questions? Contact Mike Ehlebracht.

Placing caged mussels

Snohomish County Marine Resources Council volunteers and staff place caged mussels.

There’s a Volcano on our Project Site

Water is the life blood of any city, but its systems are not always pretty. So the two-million-gallon Forest Park Low Tank was embedded into the hillside to preserve the natural character of the area and leave unfettered views. However, this presented engineering challenges. Overcoming those challenges helped us win a 2017 Grand Award from the American Council of Engineering Companies (ACEC).

Wait—What’s Down There?

The subsurface conditions were quite unusual. Maps showed them as hard volcanic rock, but our geotechnical explorations discovered a new volcanic vent, as yet unmapped. Although of great interest to geologists, volcanic vents are rarely built on. A search of case histories did not find any information to guide the process. We embarked upon an exploration and laboratory testing program to determine if the 100-foot plus pile of cinders would support the tank. We determined that the cinders were fairly uniform across the area, resulting in uniform support for the tank. Our testing further determined the magnitude of loading the cinders could support. With this information we were able to design a foundation that did not require expensive subgrade improvements or pile foundations.

Our high-tech analyses confirmed a low-tech approach would work.

Burying Infrastructure to Preserve the Natural Beauty

In many places, water tanks are constructed within large cuts that many may view as eyesores and which permanently remove natural habitat. This has been accepted over decades as a necessary compromise to provide a robust water supply to our cities. However, this compromise does not need to be accepted. Much like the trend of burying power, communications, and other utilities that were once also overhead, the Forest Park Low Tank demonstrates that water infrastructure can be adapted similarly.

Making the Water Supply Safe

Water is a critical resource in any disaster that disrupts our infrastructure. It’s common knowledge that we cannot survive for more than three days without water. During any natural disaster, it is imperative that our water remain safe and accessible. We completed a site specific seismic hazard (SSSH) as part of our work, so the tank and appurtenant facilities will withstand the next “Big One.”

Defining Ingenuity

Sometimes ingenuity is not devising something new, but applying simple methods to solve a problem. We used performance-based results to guide changes in shoring design, and confirmed landslide mitigation approaches during construction. We avoided designing expensive foundation alternatives, installing bulletproof (and expensive) secant shoring walls, and over-analyzing slope stability prior to construction. And then we buried our best work.

The one thing to remember about this project is that we did not blow our top over an unexpected volcanic vent; instead, we persevered and worked with the design and construction teams to build a successful project…and then buried it out of “site.”Finished project

Preserving Eelgrass While Remediating Legacy Contamination

Eelgrass

What do you do when the State requires you to take action, yet prohibits that action? It’s a conundrum that takes imagination and determination.

The Setup

For over 100 years, several companies used the nearshore at the former Custom Plywood site for processing and manufacturing wood-related materials that would be used nationwide. They filled the tideland with wood, ash, bricks, metal, and sediment. They left a tug, boiler ash, scrap metal, barrels and drums, aluminum cans, scrap wood, paper, sawdust and creosote-treated pilings. As if that wasn’t enough, in 1992 a fire destroyed the mill, adding dioxin (a carcinogen) to the sediment.

The Conundrum

The Washington State Department of Ecology and Hart Crowser removed most of the contamination from the property and tidelands. Despite this, there are many acres of tidelands that are still peripherally contaminated with dioxins, much of which contains healthy eelgrass habitat. The eelgrass is not affected by the dioxin contamination; the problem is that it serves as a potential pathway for human exposure (i.e., shellfish consumption). By State mandate eelgrass must be protected. (See our earlier post about the importance of eelgrass). This means that the State requires that something be done about the contamination but not at the expense of the valuable eelgrass habitat. Our current options for dealing with dioxin contamination are to either dig up the contaminated material, or immobilize/cover it to prevent the exposure to the benthic community. Either action would potentially destroy the eelgrass. What to do?

The New Approach

The solution? Remediate the sediment in place by covering the eelgrass habitat, but not burying it. Eelgrass, unlike other species of seagrass, can only tolerate a very small level of burial. We needed to determine if the eelgrass at the former Custom Plywood site could withstand deposition of very fine layers of sand that would act as a barrier (cap) to the contamination in order to protect the benthic community and the habitat overall. Our team conducted a two-year pilot study to see whether the eelgrass could tolerate a four- or eight-inch layer of sand (applied two inches at a time), rather than a single layer application that would ordinarily be used for remediation. As part of this study, our team also investigated if adding a layer of carbon could increase the cap performance so that the cap could be as thin as possible.

Diver

Diver with eelgrass/sediment sample. Photo courtesy of Research Support Services.

The Result

The data clearly showed that eelgrass at the former Custom Plywood site can survive a four-inch cap if implemented in multiple thin layers. This means that the preferred alternative for cleaning up the residual contamination is potentially feasible. The next step is to design a large scale application using the information and data gathered from the pilot study. Eventually we hope to finally cleanup the former Custom Plywood site while leaving the existing eelgrass habitat in place and functioning.

 

Diving In – The Promise of Social Marketing for Storm Water Education

 

Kapalua Bay on Maui

Kapalua Bay on Maui. The West Maui Kumuwai campaign uses social marketing to protect a sensitive watershed.

Individuals have a direct influence on storm water quality in their communities, and regulators strongly emphasize public education and involvement campaigns in municipal storm water management programs. But how can leaders convince residents to pick up after pets, reduce lawn pesticide use, and wash cars without getting soapy water in storm drains? And how can they discourage commercial and industrial workers from dumping contaminated liquids down storm drains behind shops, and to use drip pans to keep oil off pavement? These behavior changes would have a direct positive effect on the coastal and inland water resources we enjoy.

In traditional environmental education campaigns, the message is often delivered through newsletters, brochures, public service announcements, and social media. Some effort may be made to reach a specific audience, but the focus is producing a good quality educational tool. The hope is that having a good message and delivering it well will make people listen, learn and act.

But experience in educational campaign history indicates otherwise. Simply handing someone a pamphlet does not mean that a person will act on that information.

Enter social marketing. Social marketing integrates marketing concepts and tools from social psychology to influence behaviors that benefit individuals and communities for the greater social good.  While social marketing campaigns sometimes employ social media, the two are not the same. Social marketing can use a variety of tools to influence behaviors. First used in the public health realm, the practice focuses on a specific community. Research and surveys identify real or perceived barriers to change, and campaigns are designed to overcome those barriers and reward desired behaviors.

A great example of social marketing in action is the West Maui Kumuwai (WMK) campaign in a sensitive watershed on Maui. WMK is a non-profit that shines a spotlight on the actions of everyday people to promote ocean health. Through community surveys, WMK identified landscaping activities as a community concern relative to storm water pollution. WMK’s Reef-Friendly Landscaper campaign invites landscapers and gardeners to “Take the Pledge” by agreeing to a set of ocean-friendly landscaping activities. WMK then promotes those companies on its website and through social media, to keep these companies engaged and committed.

If you’ve heard of other successful social marketing campaigns related to storm water education, please let us know with a comment.

For more information about storm water services for municipalities, construction, and industry, contact Janice Marsters at janice.marsters@hartcrowser.com.

Invasions are not just military (Part 2)

 

Butterfly Bush

Butterfly bushes displace native vegetation and in spite of the name, negatively affect native butterflies. We didn’t have to go far to take this photo.

In a previous post about invasive species, we learned what invasion meant and who the invaders look like. Now let’s discuss how invasive species get a foot hold in the first place and what can be done about it.

How Invasions Happen

Invasive species can be introduced intentionally or unintentionally. They may be introduced intentionally to benefit the ecosystem by restoring habitat, increasing fish stock, or controlling pests. Unintentionally, they:

  • Are released in ship ballast;
  • Escape from fish farms;
  • Are used in recreational activities;
  • Are used as live bait;
  • Arrive through canals;
  • Are released/escape from aquariums;
  • Are used in unauthorized fish stocking; and
  • Can be introduced by many other means.

In order to successfully invade a new environment, certain biological characteristics are necessary. Many invasive species have high reproduction rates, short generations, long life, high dispersal rates, broad native range, and broad diet. However, not all species immediately survive in new environments. They can fail multiple times before flourishing. Invasion success is context dependent.

Controlling the Invasion

Strategies to control invasive species include (1) keeping potential invaders out, (2) eradicating potential invaders soon after invasion, (3) biological control, (4) chemical control, and (5) mechanical control.

Keeping potential invaders out

Keeping potentially damaging invaders out in the first place is the most cost-effective method. The danger can be reduced by monitoring the common invasion pathways such as ship ballast water, wooden packing material, and horticultural plants.

 Eradicating after Invasion

It is easier to eradicate invasive species if they are discovered quickly and population levels remain low. Even if it proves impossible to totally eliminate an invader, early intervention can keep the population at acceptably low levels. For example, Giant African Snails were effectively eliminated from Florida. Currently researchers in California are attempting to eradicate the marine green alga Caulerpa, a recent invader.

Biological Control

Biological control involves introducing an enemy of an invasive plant (for example, a disease, parasite, predator, or competitor) in an attempt to lower invader population size.

Sometimes introducing a natural enemy from the native range of the introduced pest can be effective. For example, prickly pear cactus, which invaded Australia from the Americas, has been effectively controlled by introducing a moth from South America whose caterpillar feeds on the cactus. In other cases finding an enemy from a different area (a novel association) works because the invader may not have evolved defenses to a species with which it has never been in contact. For example, a virus from South America has been used to control European Rabbits in Australia.

A disadvantage of biological control is that some agents attack nontarget species, becoming noxious invaders themselves, and it is very difficult to remove a troublesome introduced natural enemy once it is established.

Chemical Control

Although chemical pesticides can effectively control some species (for example, water hyacinth in Florida), it can have problems. Pesticides may affect non target species, can be expensive, and may only be effective for a limited time if pests evolve resistance.

Mechanical Control

Mechanical control involves using machinery or human effort to remove invaders, often manually. Mechanical control has been an effective control strategy for invasive Tamarix (arid climate adapted shrub) in the Southwestern United States. Volunteer convict labor has been used in Florida to cut paperbark trees and in Kentucky to rip out Eurasian musk thistle.

Ecosystem Management

The newest technology for managing invaders is ecosystem management, in which the entire ecosystem is subject to a regular treatment (such as a simulated natural fire regime) that tends to favor adapted native species over most exotic invaders. Because it is so new, the specific ways in which ecosystem management can be employed must be determined in each type of habitat.

Want to learn more?

Invasive species are everyone’s problem. Learn more about what you can do to help prevent them:

Washington Invasive Species Council

Washington Department of Fish and Wildlife Aquatic Invasive Species

US Department of Agriculture, Invasive Species State by State

Invasions Are Not Just Military

Atlantic Salmon

Atlantic Salmon. Photo: Maine Atlantic Salmon Commission

One of the most destructive forces on an ecosystem is a non-native species with no natural predators or other natural controls. These species can overtake their new home in an extraordinarily short period of time by multiplying, consuming prey, and colonizing, crowding out essential local species.

An invasive species is an organism (plant, animal, fungus, or microbe) that is not only foreign to a specific area or habitat but also has negative effects on its new environment and, eventually, on our economy, our environment, or our health. Not all introduced species are invasive; the distinction is how aggressively they interact with their new surroundings.

Why we Care

Invasive species are the second greatest threat to biodiversity (the first is habitat loss). Almost half of the species at risk of extinction in the United States are endangered directly due to the introduction of non-native species alone, or because of its impact combined with other processes. In fact, introduced species are considered a greater threat to native biodiversity than pollution, harvest, and disease combined. They threaten biodiversity by (1) causing disease, (2) acting as predators or parasites, (3) acting as competitors, (4) altering habitat, or (5) hybridizing with local species.

Invasive species are costly to both society and nature by:

  • Costing Americans more than $137 billion a year (Pimentel et al. 2000)
  • Impacting nearly half the species listed as threatened or endangered
  • Possibly devastating key industries including seafood, agriculture, timber, hydro-electricity, and recreation
  • Impeding recreation such as boating, fishing, hunting, gardening, and hiking
  • Spreading easily by wind, water, animals, people, equipment, and imported goods
  • Increasing the frequency of localized wildfires and adversely affect watering availability
  • Destabilizing soil and alter hydrology of streams, rivers, lakes, and wetlands

Washington State Invasive Species Examples

There are over 50 priority invasive species of concern in Washington State. Here are a few examples that threaten Western Washington.

Atlantic Salmon

Atlantic salmon (many genetically modified) are raised along the Washington and British Columbia coasts; escapes from these aquaculture operations concern fishery biologists and others working to restore native Pacific Northwest salmon runs. As of 2006, the Aquatic Nuisance Species Project states that there have been sightings of juvenile Atlantic salmon on the West Coast. The last reported sightings were on Vancouver Island in 2000.

In recent years there has been specific concern about the potential impact on wild salmon stocks from sea lice (Lepeophtheirus sp.), originating from net pens of Atlantic salmon in British Columbia. Sea lice can kill juvenile fish, even at low infestation levels.

Spartina

Spartina

Spartina flowering in estuary
Photo: Washington State Magazine

Spartina species are aquatic grasses that grow on the mud flats and marshes of Puget Sound and our coastal estuaries. The plants tend to grow in circular clumps called ‘clones’ and are bright green. One particular species, Spartina anglica, was introduced either in shipments of oysters from the East Coast or as packing material in ships’ cargo. It creates large monocultures that outcompete native plant species for space, including rare and endangered plant species, reducing marsh biodiversity and ecological functions.

European Green Crab

European green crab

Juvenile green crab began showing up in Washington waters in 1998. Photo: Washington State Department of Fish and Wildlife

The European green crab is a small shore crab that is not necessarily green like its name implies. It typically is found in high intertidal areas and marshes in coastal estuaries and wave-protected embayments, and can live on a variety of surfaces including sand, mudflats, shells, cobble, algae, and rock. It is an opportunistic feeder and aggressive invader. It is native to the eastern Atlantic from Norway to North Africa.

The European green crab is a ravenous predator that eats small crustaceans and many other plants and animals, and can have dramatic negative impacts to native shore crab, clam, and oyster populations. First introduced to the East Coast of the US, green crabs are believed to have caused the collapse of the soft-shell clam industry in New England; their digging habits also have slowed eelgrass restoration efforts. One green crab can consume 40 half-inch clams a day, as well as other crabs its own size. On the West Coast, green crabs were introduced to San Francisco Bay either via ballast water or through the lobster trade. Further invasion north is facilitated by strong advective currents that are associated with El Nino events. The 1998 event brought crabs as far north as Vancouver Island; luckily populations have not established yet. This year’s El Nino may prove strong enough to bring crab larvae into Puget Sound and British Columbia again. How severe the invasion will be, only time will tell.

Scotch Broom

Scotch Broom

A member of the pea family, Scotch Broom has pretty flowers but an aggressive demeanor. Photo: King County

Scotch broom (Cytisus scoparius) is an upright shrub with yellow flowers in the pea family. It grows primarily in open, dry meadows and along roads. It is an aggressive early colonizer and typically shows up in recently disturbed areas. A European native, scotch broom crowds out native species and negatively impacts wildlife habitat by creating vast monocultures. It can form dense, impenetrable stands that displace farmland and/or prevent native species from colonizing. Scotch broom also produces toxic compounds, which in large amounts can cause mild poisoning in animals such as horses.

Coming up: in Part II, we will discuss how invasions happen and what can be done to stop them.

For more information, contact Jason Stutes at jason.stutes@hartcrowser.com.

References: Pimentel, D., Lach, L., Zuniga, R., Morrison, D., 2000. Environmental and economic costs associated with non-indigenous species in the United States. BioScience 50 (1), 53–65.

Applying Net Environmental Benefit Analysis to Contaminated Sites

Exxon Valdez oil spill site

Exxon Valdez oil spill site.

First, do no harm….

Or at least don’t do more harm than good.

That’s the idea behind NEBA—Net Environmental Benefit Analysis—as applied to the cleanup of contaminated sites. As defined by a vintage 1990s Department of Energy paper on the subject, net environmental benefits are:

“…the gains in environmental services or other ecological properties attained by remediation or ecological restoration, minus the environmental injuries caused by those actions.”

Spills like Exxon Valdez Spurred the NEBA
The NEBA concept originated with the cleanup of large marine oil spills. One of the first formal considerations of Net Environmental Benefits was the cleanup of the Exxon Valdez oil spill in Prince William Sound, Alaska in 1989. After the spill, the U.S. National Oceanic and Atmospheric Administration (NOAA) looked at whether high-pressure, hot water washing of unconsolidated beaches might actually do more harm to the intertidal habitat—and the plants and animals that depend on it—than just simply letting the oil degrade naturally.

Since then, NEBAs have been used for a few other types of cleanups, including metals contamination in wetlands and organic contamination in sub-tidal sediment, but only infrequently and on an ad hoc basis.

No current NEBA Guidelines, However…
Formal consideration of net environmental benefits has not been more widespread in cleanup decisions, probably because federal and state cleanup frameworks, such as Washington’s Model Toxic Control Act (MTCA), do not explicitly allow consideration of the harm of the cleanup itself and don’t provide guidelines for when the process would apply and how the benefits and impacts should be evaluated.

But that might be changing. At least it is in Washington State, where the Department of Ecology thinks that the NEBA’s time has come. Ecology is working on new draft Terrestrial Ecological Evaluation (TEE) guidance that, for the first time, lays out the implementation of NEBA at cleanup sites under MTCA.

NEBA and Abandoned Underground Mines
In conjunction with Ecology, Hart Crowser has already “test driven” the NEBA concept as it applies to the cleanup of abandoned underground mines. Many of these sites pose risks to terrestrial plants and animals because of the toxic metals such as copper and zinc left behind in tailings and waste rock.

Although the risks to individual organisms living on the waste material might be high, the overall risk to plant or wildlife populations are often fairly low because the extent of the waste material is so small. Nonetheless, the remedy selection process under MTCA would typically lead to a decision to cap the contaminated material with clean soil or to dig it up and haul it away to be disposed of elsewhere.

Bringing Common Sense into Cleanup Decisions
But what if the cleanup involved building an access road? Through mature forest? Or up a steep, exposed mountain side? Or across a stream or wetland? How are those habitat or ecosystem injuries balanced against the benefits of the cleanup itself? Ecology’s upcoming NEBA guidance should go a long way to addressing these dilemmas and bringing some common sense into certain cleanup decisions.

“Especially Valuable Habitat”
The new guidance is expected to introduce the concept of “Especially Valuable Habitat” and how to use it as a threshold for judging whether or not a NEBA may be appropriate for a particular site. It’s also expected to allow some flexibility regarding how injuries and benefits are quantified and balanced.

In the meantime, check for updates on when the new guidance is expected at Ecology’s website.

eDNA: A Powerful Tool for Scientists and Managers

Sampling eDNA in a stream

Using a pump to filter stream water to get an eDNA sample to determine whether salmon are in the stream.

Detecting the presence or absence of a species of interest is a common challenge for scientists and fisheries managers. Whether you’re interested in protecting an endangered species or removing an invasive species, knowing where they are or are not is crucial. Many techniques can be time-consuming or damaging to the local environment, and they don’t always work on more cryptic species. An emerging technique has the potential to address some of these pitfalls: environmental DNA, or eDNA.

eDNA is DNA fragments found in the environment (usually in soil or water) that come from an animal. Animals shed cells from their bodies through routes such as mucous, feces, or skin flakes. Each cell contains a full set of nuclear DNA and many copies of mitochondrial DNA. As these cells break down, the DNA is released into the environment. A researcher can collect samples (such as water or soil samples) and analyze any DNA present (typically mitochondrial DNA) for a match with the target species.

A useful application of this technology is to learn when and where endangered/threatened salmonids are present. Knowing which drainage systems these fish spawn and rear in is essential to managing and restoring their populations. Scientists can take water samples along river and creek systems where they suspect salmon will be. They then analyze the water samples for salmon DNA, and generate maps of fish distribution. If sampling is repeated over time, temporal trends along with spatial trends in salmon populations can be mapped, providing powerful information to managers and policy-makers.

In the future, eDNA may also help determine how many of each species of interest are in a given area. Research into the relationship between quantity of eDNA obtained and population numbers is ongoing.

For more information on eDNA methodologies, see this USGS factsheet.

Chase the Rainbow (Smelt)

Kuskokwim River

Kuskokwim River

Individual Rainbow Smelt Eggs

Individual Rainbow Smelt Eggs

We got the call at 3:30 in the afternoon that they were 10 miles below Kalskag. At 6 a.m. the following morning we were on plane, bound for the Alaskan Bush on the Kuskokwim River in search of spawning rainbow smelt. These are river spawners and an important subsistence species for remote Alaskan villages. Concerns that proposed increases in barge traffic may disrupt or scour spawning areas prompted a study to identify where fish spawn and the types of habitats they use. And on the Kuskokwim, they travel fast; getting there in time to study them is one of the biggest challenges.

Rainbow smelt begin their spawning migrations shortly after the ice breaks up in spring. Through word of mouth, Alaskan villagers begin fishing as smelt move upstream. In 2014, smelt moved rapidly, moving upstream from village to village for nearly 200 miles at rate of about 30 miles per day. They spawn just as quickly and immediately leave the river for the ocean. Scientists must plug themselves into this word of mouth network and be ready to fly to remote areas on a moment’s notice.

Upon arriving, we began helicopter and boat surveys covering over 50 miles of river to find and follow the fish, and document the uppermost extent of the migration. This lasted a mere two days before the fish were gone, presumably having spawned and moving back downstream. Next, discrete spawning grounds needed to be identified in a river that flows more than 50,000 cubic feet per second. Eggs are also tiny (0.5 millimeter). Sampling included collecting and examining fish for spawn condition, collecting substrate samples, and sieving substrates for eggs and grain size to determine spawning locations and substrate preferences. All studies needed to be conducted in as little as two weeks before the eggs hatched and all traces of the fish were gone.

Despite all of the challenges, field efforts were successful. Results show that fish spawn on large, low gradient gravel bars in water between 5 and 14 feet deep. Gravel to cobble substrates were most commonly used. Data will be used to better define the potential impacts of barge routes and as a tool to help manage the resource. The ultimate goal is to allow the safe transport of commerce in the river while minimizing impacts to this unique resource for native Alaskans in this remote part of the state.

Rainbow Smelt

Rainbow Smelt