Trinity River in Douglas City. [Kiana Abel, Trinity River Restoration Program]
For the year ahead the Program will continue with both short and long-term monitoring projects. Long-term monitoring projects include,
outmigrant monitoring (tracking the number and size of young fish heading out to sea)
adult escapement monitoring (tracking the number and size of adult fish returning from the sea).
Shorter duration studies to examine the flow changes include;
acoustic monitoring of rock movement,
and investigating the benthic macroinvertebrate (fish food) response to the flows.
Also, this year we will wrap up a review of our long-term monitoring and modeling efforts and bring recommendations forward on how to better measure our progress.
We will complete the adult Chinook Limiting Factors Analysis, which should give us insights regarding what factors are limiting the return of adult Chinook salmon along with gaming the associated scenarios to help us understand how to improve the use of our tools.
Lastly, we will continue to support the development of a new approach to long-term operations of the Trinity River Division, which should give us better protection of river temperatures in drought years and give us more flexibility with managing environmental flows.
Publications to look out for in 2026
Lindke, K. T., Video monitoring of fish passage at Willow Creek weir: feasibility of validating mark-recapture run size estimates.
Bridegum, J., D. Goodman, T. Daley, R. Smit, J. Boyce, O. Black, J. Alvarez, and K. De Juilio. The Effects of Restoration Actions on Juvenile Salmonid Rearing Habitat in the Trinity River Restoration Reach at an Index Streamflow, 2009 to 2017.
Martel, C. J. Alvare, Z. Reinstein, and K. T. Lindke, Fall Chinook Redd Environmental Conditions and Egg Survival to Emergence in the Trinity River.
Gaeuman, D., K. De Juilio, and C. Laskodi. Efficacy of two-dimensional modeling for assessing spatial variability in stream temperatures.
The Trinity River Restoration Program will work toward the completion of three Trinity River channel rehabilitation projects along with five watershed grantee projects all slated to be implemented in the next year.
In 2026, the Trinity River Restoration Program will be closing out our long-term gravel processing site (Sawmill) in Lewiston in tandem with implementing floodplain restoration and side channel maintenance work at the site. The project aims to significantly improve habitat conditions for aquatic and riparian wildlife in this important area close to Lewiston Dam.
Additionally, the Implementation Branch will be diving into the design phase for most of the remaining 47 sites identified in the 2000 ROD. Closest to implementation are the channel rehabilitation projects in Junction City at Evans Bar and Sky Ranch, and the Rush Creek Confluence in Lewiston, likely to enter work phases beginning in 2027. At Evan’s Bar, TRRP intends to enhance habitat availability for juvenile fish, along with maintaining access to private parcels in the area while improving access at the public boat launch. The remaining site designs, which include Sky Ranch, McIntyre Gulch, and middle Steiner Flat, will start to paint the picture of what the 40-mile restoration reach will look like as the program of work identified within the 2000 ROD nears “completion”.
Watershed Grantee Projects
Through our Watershed Grantee Program, the Implementation Branch will continue to collaborate on five projects to improve conditions in Trinity River tributaries in 2026.
Deadwood Creek Sediment Reduction Project – Northwest California Resource Conservation & Development Council (5Cs)
This project intends to improve sediment delivery in Deadwood Creek, the first major Trinity River tributary below Lewiston Dam. The project will remove legacy mine tailings from Mill Gulch, decommission Thorne Gulch Road, install and enhance 12 rolling or critical dips, remove abandoned vehicles and debris from stream channels and floodplains and build stream enhancement features in Thorne Gulch.
Salt Creek Floodplain Restoration – The Watershed Research and Training Center
This project aims to improve 2,000 feet of heavily degraded salmonid habitat along Salt Creek, a South Fork Trinity River tributary, by reconnecting the creek to its historic floodplain using engineered and process-based restoration techniques. The project will increase aquifer recharge and storage for slow release to temper a thermal barrier for salmonids, restore geomorphic functions that will improve salmonid spawning gravels, create pools for summer cool water refugia, increase habitat heterogeneity for winter flow high-velocity refugia, and improve native riparian flora, all of which will increase the resilience of aquatic species from the impacts of climate change. Implementation is scheduled for summer 2026.
Water Resiliency in the Greater River Trinity Watershed for Aquatic Ecosystem and Human Domestic Needs – The Watershed Research and Training Center
The organization is tasked to plan and implement storage tank arrays and establish long-term forbearance agreements to reduce annual water withdrawals from key tributaries to the Trinity River during the summer low-flow period. The project will increase the quality and quantity of natural habitats crucial to the survival of anadromous fishes and aquatic organisms in the Trinity River Watershed. Implementation for two landowners along Brown’s Creek is scheduled for spring 2026.
East Branch East Weaver Creek Migration Barrier Removal – Northwest California Resource Conservation & Development Council (5Cs)
This project will replace an aging culvert that has become a fish passage barrier on the East Branch of East Weaver Creek. The new infrastructure placement will open nearly 2 miles of habitat for anadromous species of the Trinity Watershed.
Weaver Creek Habitat Restoration Implementation – The Yurok Tribe Fisheries Department
The Yurok Tribe Fisheries Department will complete the NEPA process and work towards rehabilitation along the upper section of Weaver Creek, a tributary to the Trinity River. The project will control the spread of invasive plant species, establish habitat connectivity during summertime baseflow conditions, and support populations of threatened Coho Salmon through enhanced floodplain an instream habitat conditions. The Yurok Tribe is collaborating with the Nor Rel Muk Wintu Nation, Federal land managers, the Weaverville Sanitary District, and adjacent landowners for this restoration project.
Drone photo of the Oregon Gulch site in the summer of 2025. [Elliot Sarnacki, TRRP]
As we enter 2026, let us pause to reflect on this past year, which was the 25th year of the Trinity River Restoration Program. I’m sure that most will agree that 2025 felt decidedly tumultuous, but we managed to overcome a lot of hurdles and get important work done.
Although we said goodbye to an unprecedented number of TRRPers from across our partnership, the pace of our work did not slow down. While we cannot replace the friendships and personalities of our colleagues who no longer roam our meetings and hallways, those that remain have showed great resolve in their dedication to this program and its mission.
Last year, we completed the Watershed Restoration EA, an ambitious document that will dramatically streamline the environmental compliance process for not just the TRRP’s restoration work, but also for other partners in the watershed. The document was a collaboration with the Bureau of Land Management, the US Forest Service, and our office, and was a heavy lift by many dedicated individuals over several years. We are already seeing the benefits of their hard work with the 2026 construction season approaching.
We abruptly lost our long-term outreach grant with the Trinity County RCD late last spring, but our relationship with them endures. We are actively working on ways to share capacity and continue the work that we do together. Popular events like Science on Tap and youth outreach camps such as the Weaverville Summer Day Camp will continue into 2026.
The Upper Conner Creek restoration Project was completed in 2025. [Elliot Sarnacki, TRRP]
We completed the Upper Conner Creek restoration project. The project rehabilitated nearly 15 acres of floodplain habitat and filled a final puzzle piece of a patchwork of channel restoration projects both up and downstream of the area. The design was the third largest design we have ever implemented in terms of excavation volume. This project saw a significant amount of input from partnerships and stakeholders, leading to a project that met the needs of many while keeping the goal of habitat enhancement for fish and other wildlife at the center. Watching flows from these last several December storms spread out on all that new floodplain has been very exciting – the site looks great and we look forward to watching it evolve.
Speaking of flows, we are now in our second year of implementing the full winter flow project ruleset to better manage and study our environmental flows. For a second year in a row the atmosphere delivered a Christmas storm triggering a synchronized storm pulse. This flow gave the river a healthy scrub (especially up by Deadwood Creek) and set the stage for a vibrant food web to develop as salmon emerge from the gravel.
In the broader Klamath-Trinity watershed, we saw an incredible, unhoped-for number of adult salmon pass the former Klamath dam sites and make it into the upper watershed. Partners in the program were instrumental in making that happen, and there is little doubt the dam removals will pay dividends for the Trinity as well – a rising tide lifts all boats.
On the left is poison oak, and the right is skunk brush. Notice the distinct ‘stem’ on the central leaflet on the poison oak plant. Skunk brush leaflets do not have this feature. [Simone Groves, Hoopa Valley Fisheries Department]
Editor’s note: The shrub with the common names which include skunk brush, basket bush, fragrant sumac, lemon sumac, and lemonade bush is known across North America as both Rhus trilobata and Rhus aromatica. The nomenclature in this document follows McBain and Trush (2005) and refers to the plant as Rhus trilobata.
Have you ever walked in the woods and tried to identify poison oak along the path? Some folks walk with extreme caution as soon as they step from pavement and defined trails, driven by fear of injurious rash caused by this plant. The most common way that I hear folks identify poison oak is through a common rhyme “leaves of three, let it be.” This is an easy phrase to remember, but there are some loopholes in this simple rhyme. There are several look-alike species that cause no harm, and are in fact quite tasty, and can be eaten. Let’s start with the commonly defined ID features used in the Jepson manual to distinguish the two genera.
Poison Oak (Toxicodendron diversilobum) has axillary flowers which appear between the leaf axles with a pedicel, or stem at the base which causes the flowers and fruit to be spaced apart; leaflets adaxially shiny or oily-looking on the top; fruit creamy white or papery looking.
Skunk brush (Rhustrilobata) (also called basket bush, lemon sumac, fragrant sumac, and lemonade bush) flowers appear on the ends of the branches, also called “terminal”; flowers are often nearly sessile or appear tightly packed; leaflets dull, not very shiny; fruit red and often sticky. There’s an interesting additional flower mannerism in skunk brush – the flowers often are only male or only female on individual plants, but sometimes bisexual flowers can also be found on plants, this term is called polygamodioecious. This is why a whole area will have no fruit, and then a patch of plants might be loaded full of fruit.
Speaking of its red fruit, skunk brush’s other common names, lemonade bush and lemon sumac, refer to the berries. They have a sour, lemony flavor to them. It is said that early pioneers steeped the berries in water, and then added sugar to make lemonade. The berries are also eaten directly and are considered an important food source by some Native American tribes. Many wild animals consume the berries of both poison oak and skunk brush, particularly birds and small mammals, although they are not a preferred food source. Their tendency to stick to the stems through the winter makes them good emergency food for animals when other foods are scarce.
Skunk Brush (Rhus trilobata) with fall berries. [Simone Groves, Hoopa Valley Fisheries Department]
Expanding beyond the features that the Jepson uses for ID there can be a lot more subtlety of distinguishing observations between the two species. The more that you look at these two, the more you will learn to differentiate between them in your own way! Here are a few more features that I have noticed over the years.
Leaves
Remember “leaves of three, let them be”? Well the more accurate saying should be, “leaflets of three, let them be” because according to plant anatomists, the three “leaves” on a poison oak plant are actually a single leaf, divided into three leaflets. Poison oak appears to have a stem on the terminal leaflet which separates it from the basal lobes. The leaves often have 3-dimensionality to them, either with ruffled edges, or a central crease along the midrib of the leaf, with venation standing out as slightly white when viewed from above. Any leaf features on poison oak can be highly variable and thus expect it to surprise you at times. As field botanists often joke that poison oak will often take on the look of nearby plants.
Skunk brush tends to have the front leaflet be a little larger and the back appear slightly reduced in size. These leaves do not have a stem attaching the leaflets together. The leaves tend to be extraordinarily flat or could be described as “2D.” Often times the venation is only distinctly visible from the abaxial or underside of the leaf. Sometimes there is a little trench-like crease from the topside but the veins don’t stand out looking down on it.
The last feature that is helpful for differentiating these two species, is the color and mannerisms of the stems of each plant, even when dormant. Poison oak tends to have yellowish stems, often times with hibernating buds that look like little pink primordial hands. Poison oak is also known for making little adventitious roots on the branches which helps it climb trees and spread aggressively over the ground. It isn’t unusual to see poison oak growing as either a shrub or a vine (but it’s not the same as ‘poison ivy’, which is not found in California.
The “yellowish” stems of poison oak. [Simone Groves, Hoopa Valley Fisheries Department]
Skunk brush has branches that look ashy grey or pinkish purple and in early spring they tend to be layered in a tender fuzz that is reminiscent of the velvet covering a young deer’s antlers. Also, the smell of skunk brush is distinctly pleasant, both when cut and when burned. One might imagine these sticks being used for incense, or something similar.
The tender fuzz covered stems of skunk brush. [Simone Groves, Hoopa Valley Tribal Fisheries]
Both species tend to come out of winter dormancy around the same time. However the first features to awaken in poison oak are its new shiny leaves, whereas the first feature to appear for skunk brush, are the flowers. Often times the timing of this awakening from dormancy is highly variable year to year and can track the warmth changing around the landscape in a very intimate way.
Comparison of the two species in early spring when poison oak shows leaves first and skunk brush’s flowers are first. [Simone Groves, Hoopa Valley Fisheries Department]
Initially, botanists placed both poison oak and skunk brush in the same genus- Rhus. This name is Greek for ‘rhous’ which means flow, or stream. Some have thought that this might refer to the sticky sap that is excreted when cut, but others have rejected this claim. The reclassification of poison oak to its own genus “Toxicodendron” occurred in the early 20th century as the genus was given definition and separated out those representatives within Rhus that caused skin irritation. Toxicodendron means “poison – tree” in Greek which was also a contentious definition because technically the plant is not poisonous, but is an irritant, and in fact has many medicinal and beneficial properties. In Hupa language the word for poison oak is k’e:k’ilye:ch’. In Yurok the word for poison oak is me’yk’welep’. The Karuk word for poison oak is kusvêep.
Urushiol is the chemical present in the Toxicodendron genus that is renowned for irritating the skin. This oil is described as similar to machine oil in its difficulty to remove. Some recommendations suggest removing it using a sudsy soap and an abrasive scrubbing surface under cold water. Also, some home remedies recommend rubbing clay or dirt on fresh oils as it can absorb the oils and reduce the interactions with your skin cells. According to the National Library of Medicine, the reaction caused by urushiol is a Type IV Hypersensitivity reaction which is often stimulated in 48-72 hours after exposure and is a T-cell mediated immune reaction, suggesting that it is the between-cell interactions that cause the body’s immune response to the oils.
Urushiol is the chemical present in the Toxicodendron genus that is renowned for irritating the skin. This oil is described as similar to machine oil in its difficulty to remove. Some recommendations suggest removing it using a sudsy soap and an abrasive scrubbing surface under cold water. Also, some home remedies recommend rubbing clay or dirt on fresh oils as it can absorb the oils and reduce the interactions with your skin cells. According to the National Library of Medicine, the reaction caused by urushiol is a Type IV Hypersensitivity reaction which is often stimulated in 48-72 hours after exposure and is a T-cell mediated immune reaction, suggesting that it is the between-cell interactions that cause the body’s immune response to the oils.
As with many plants in the California landscape, both poison oak and skunk brush have a fire relationship. Although poison oak burning can aerosolize the urushiol, if the fire develops to just the right amount of heat and time of day, a completely safe fire can “stand up” and send the toxic smoke harmlessly into the upper atmosphere. Some indigenous descriptions report that the current prevalence of poison oak in forest understories is due to the lack of short fire return intervals on the landscape. Skunk brush was used by many tribes in California as a basketry stick. These stems were burned, just as hazel was for its shoots. In my personal experience burning with North Fork Mono led by cultural fire practitioner and Tribal Chairman, Ron Good, when the color of the ash turns purple, it can indicate that the fire and embers are the right intensity and is cool enough to cultivate the healthy regrowth of the plant. With burning and fire intensity, ash color and burned soil color as well as charcoal remains can all be an indicators of the temperature of the flames and their effects on the plant and soil communities. For more information dig into the resources at the FRAMES federally hosted fire effects resource page.
A common medicinal concept held by many of the tribes in our northern California region is that the medicine can be found near the cause of the problem. Poison oak is the classic example of this. Mugwort is a strong medicine for neutralizing poison oak, in particular salves made from it, but also a tea, taken internally can soothe the body’s reaction. Other common medicines include manzanita and madrone bark which a cooled tea of these can soothe the blisters and calm the body’s reaction. This idea can remind us that rather than thinking of the world as full of dangers and poisons that lie just beyond the edge of the path, rather that medicines and foods are always near to provide support and soothe the ails that arise along the way.
Simone Groves, Riparian Ecologist, Hoopa Valley Tribal Fisheries
Simone is first generation California transplant of Scottish descent raised in the unceded territories of the Raymatush in the rural west peninsula of the SF Bay where farmers, farm workers and hippies form the heart of the small town. She graduated in 2016 from Humboldt State University with a BS in Botany and has worked in the outskirts of rural Humboldt county on Natural Resource and Land management since 2013. She is passionate about plants and their interactions with dynamic systems as a mechanism for relearning our human-landscape interdependence.
Oak woodlands near Weaverville in 2020. [Kiana Abel, Trinity River Restoration Program]
As the weather starts to warm, California’s hillsides turn golden as grasses dry and take on a reflective sheen. Not only does California’s nickname “the Golden State” refer to it’s historic connection to the gold rush, it also refers to the rolling golden hills of native flowers, like the California golden poppy and less distinct but no less important the native grasses of California. California’s grasslands are a subtle and complex community of individuals which each invite the passerby to slow down and look carefully. One can also trace the last vestiges of water and see where the moisture lingers on the landscape. These last little patches of green show photosynthetic organisms reluctant to take shelter from the summer heat.
Historically it was farmers who were in touch with the detailed eye and mind tuned to the life cycle of grasses. To be a farmer who makes hay, is to understand the boom-and-bust lifecycle of being a grass. As many ranchers will say – being a rancher is really learning to be a grass-farmer. It is an intimate relationship to learn the rhythm of grass growing, to slow down and tap into the cycle. There is a critical threshold in the season, where all the grasses race at a break-neck pace to produce seed. As part of a grass’s strategy, it tracks day-by-day weather in a race to produce and distribute seed in the heat of summer. As a hay producer, it’s best to harvest your hay before all the energy has gone up into the seed and hardened off. This will allow some of the sugars to be readily available for consumption when an animal goes to eat it. If the grass is too far along towards producing its seed, the sugars in the grass become all locked up and stored into their long term, harder to digest form.
If you’ve ever been curious about grasses, Trinity County has some beautiful remnant examples of grasslands clinging on to the edges of areas where mining did not bury their seeds beneath the sorted rocks. When identifying grasses, I find that it can be easiest to start with the things that you’ll see a lot of and try to find “friends” in the population. Each person relates to plants differently, but I find that it can help to try to find a few native grasses and a few non-native grasses to learn to train your eye to their differences. Knowing a handful of native and a handful of non-native grasses is a great place to start.
Here is Bromus diandrus or “rip gut brome” [iNaturalist John Lynden] so named for its ability to get the long awns of the plant (the bristle or hairy growth that helps carry a seed) all tangled and poking into the skin, mouth or gut of herbivores munching in grasslands. Rip gut brome was introduced to California from European Mediterranean areas and is considered invasive and harmful to crops and foragers alike.
Because grasses are difficult to discern, I’ve noted to visit and reexamine them as the season progresses. With each stage of development from flower to seed each species can change significantly showing their true colors. As Bromus diandrus develops it changes colors and can look quite purple.
Here’s a common native grass that looks quite similar to Bromus diandrus. A cousin to B. diandrus, this is Bromus carinatus or California brome [Rob Irwin via iNaturalist] which is a native bunch grass that can be found in many types of habitat.
California brome pollinates via wind, is a great asset in erosion control and is well adapted to survive under a regime of frequent fire. It is also an important food for bear, elk, black tailed deer and seed eating bird species of California.
Look closely when comparing these two brome species by looking at the hair-like awns sticking out of the flower.
In this photo B. carinatus is on the Left and B. diandrus is on the right. [Simone Groves, Hoopa Valley Tribal Fisheries Department]
Non-Native Grasses
As livestock were introduced to California, farmers often seeded grasses as forage so their animals would be well-fed where they landed. The easy and short list of these species is a great starting place to begin to recognize grasses. These species include orchard grass (Dactylis glomerata), rye grass (lolium perenne), wild oats (Avena sp). Avena or wild oats are the same oats that we eat for oatmeal or give to our horses for grain.
And now for some of the native species of grasses! There are three classics to get to know in our area which are blue wild rye (Elymus glaucus), California oatgrass (Danthonia californica) and purple needle grass.
Blue wild rye (Elymus glaucus)
This grass is a tall hearty looking grass with a large seed. It’s very hard to photograph the whole seed head because it is so long and tall, but once you get to know this plant it’s quite distinct. Blue wildrye provides excellent habitat for birds, mammals and waterfowl, can be used to stabilize streambanks, and is very tolerant to fire. Early in the season it provides forage and the seed is an excellent summertime food source for native mammals and birds [USDA Blue Wildrye (Elymus glaucus) Plant Guide].
California Oatgrass(Danthonia californica)
Danthonia as the genus that represents a variety of native oats, and when you tune your eye you’ll notice slight variation within the group along with some similarities. Their inflorescence (arrangement of the flowers on a plant) is composed of 3-5 spikelets and it is a pretty distinct recipe once you start to recognize it. They have relatively short peduncles (stalks that hold the flower or seed), only about 1-2 feet above the ground and their most distinctive feature are their “hairy arm pits.” Danthonia tends to have very hairy leaves and sometimes particularly long hairs right where the leaf separates from the stalk. Danthonia also looks to me like a little field of tiny stars, as they stand in such a distinct pattern along the ground.
California Oatgrass (Danthonia californica). [iNaturalist]
Lastly, Stipa pulchra, recently renamed to Nassella pulchra and commonly known as purple needlegrass is a grass that I – personally as a plant person – have heard a lot about throughout the state. Purple needle grass is the most widespread native grass in California and was named the “state grass” in 2004. In my experience I’ve have never seen it doing quite as well as the populations you can find here in Trinity County. This plant has long awns similar to rip gut brome but is soft to the touch while brome is typically quite coarse and harsh.
Purple needlegrass is drought tolerant and produces a lot of seed which helps to suppress non-native grass species. This grass supports native oak habitats and provides nursery habitat for caterpillars and butterflies of California.
Getting to know grasses is a process of revisiting them frequently to see the way that they change through the year. Touching and observing their basal leaves versus their flowering stalks can help you get to know the ways that they are similar and different from each other. To me, the jovial angle that each grass holds its seed is an expression of its personality and projects attitude. As the seeds mature, usually the stems of the grass start to grow heavy, and once the seeds are dispersed, they’ll spring back up again.
Grasses are a huge part of the plants that we see in our daily lives. Their role creating tiny holes for insects to live in and deep roots which hold our soils together are foundational to a healthy landscape. It’s easy to overlook the niche of grasses when we all spend much of our time trying to weed whack them down. I encourage you to try to take that extra moment to see if you can identify if a grass is native or non-native, bunchgrass or annual grass. These little details are small pieces of history that we used to know in times long past.
iNaturalist see individual links for details for each species
Simone Groves, Riparian Ecologist, Hoopa Valley Tribal Fisheries
Simone is first generation California transplant of Scottish descent raised in the unceded territories of the Raymatush in the rural west peninsula of the SF Bay where farmers, farm workers and hippies form the heart of the small town. She graduated in 2016 from Humboldt State University with a BS in Botany and has worked in the outskirts of rural Humboldt county on Natural Resource and Land management since 2013. She is passionate about plants and their interactions with dynamic systems as a mechanism for relearning our human-landscape interdependence.
Wait, bats? Of the river? Yes! A river is more than its bed and banks, it is also intricately tied to the valleys, canyons, and forests through which it flows. Many North American bats are tightly associated with proximity to both forest cover and water (e.g. Dixon 2012), and the bats of the Trinity River watershed follow suit. In fact, some of our bats do almost all of their foraging over and near water, which in a dry, mountainous landscape like ours, means over the Trinity River and its tributaries.
Bats fly into a Texas sunset. [US Fish and Wildlife Service]
Bats are the second largest order of mammals in the world, with >1,400 species on every continent except Antarctica, though a majority of those species are in the hyper-diverse tropics. The Klamath Mountains, through which the Trinity River flows, are home to at least 18 species (Reiss, Kauffman, and Feldman 2022). Some of these are year-round residents and are known to hibernate locally, whereas others migrate to warmer climates during the winter. All of our local bat species echolocate, meaning they essentially “yell” in very high frequency sound and then listen for the echoes (the same concept as sonar), which helps them navigate and feed in a dark world.
While the incredible worldwide diversity of bats includes many unique feeding styles such as nectar-feeding flower pollinators, fruit eaters, and (a bat fan favorite) bats that fish for food like the super cool fish-eating myotis, all of the bats in the Trinity watershed eat invertebrates like insects and spiders. That said, there’s a remarkable range of ways that they do that. Let’s take a look at a few of the species that call the Trinity River watershed home.
Myotis species
A little brown bat. [USFWS/Ann Froschauer]
Of the bats discussed here, the five or more small, brown, round-eared species of Myotis in our area are perhaps the closest to what people think of when they think of a “bat”. Their appearance exemplifies the German word for bat, Fledermaus or “flutter mouse”, though bats are much more closely related to deer, whales, and carnivores than to rodents.
Yuma myotis (Myotis yumanensis) are among the most frequently encountered species in the region and are “aerial insectivores”, meaning they forage on flying insects. They can be found flying along forest edges but most commonly over slow-moving water, typically only a couple feet above the river. This is because while they will also take things like moths and beetles, they are strongly predisposed to hunting emerging aquatic insects like caddisflies and midges. They make low, repeated passes over water smooth enough for their echolocation to detect the disturbance of insects on the waters’ surface. In areas where few large trees are found, they will form maternity roosts in buildings; these are where large groups of females gather together to raise their pups until they are old enough to disperse. However, in areas of the West including parts of the Trinity River where there are healthy riparian areas with large, old trees, they will roost in things like hollowed-out old cottonwood trees. This is one of the reasons that the Trinity River Restoration Program attempts to avoid impacts to mature riparian forests when building our restoration projects.
Another Myotis worthy of note is the little brown bat (Myotis lucifugus). While they are less abundant than Yuma myotis in the Trinity River region (Pierson and Rainey 2007), they are strongly predisposed to roosting in buildings and thus relatively commonly encountered. They are noteworthy in that, while fairly generalist in their feeding habits, they eat disproportionately large numbers of mosquitoes, making them allies of their human neighbors (Wray et al 2018). They have quite a large range, extending from the subarctic to the southern US, and through the late 2000s were among the most common bats on in North America. However, they are now classified as endangered by the International Union for Conservation of Nature because of the catastrophic impacts of an introduced disease called white-nose syndrome; it is estimated that the eastern and midwestern populations of the species have declined by 90% since 2010.
Little brown bat (Myotis lucifugus) in a historic building. [Mike Dixon, Bureau of Reclamation]
Pallid bat
A pallid bat (Antrozous pallidus). Photo originally posted on ANAMALIA by Michael Durham/Minden Pictures, BCI
In contrast to the myotis bats described, pallid bats (Antrozous pallidus) are quite large, with a wingspan of up to 16 inches. Beyond their large size, they also have enormous ears that can be a third of their body length. This is because rather than catching insects on the wing, they are gleaners, meaning they hunt prey on structures or, in their case, the ground. They are still capable of echolocation, but their over-large ears also allow them to listen for the sounds of their prey and target them that way. They are particularly fond of scorpions, of all things. Their inconsistent use of echolocation and ground-hunting behavior also means they tend to hunt in more arid or open areas, but they still stay relatively close to water. They frequently roost in trees in northern California (Baker et al. 2008) but can also be loyal users of strategically located buildings as night roosts. Night roosts are places that bats hang out for a variety of reasons including rest, digestion, picking apart large prey items, and various social interactions including information sharing (Ormsby et al. 2007). For several years, I have observed congregations of 5-20 pallid bats in the same corner under my eaves almost every night when overnight lows temperatures exceed 45oF. I appreciate them keeping the front of my house scorpion-free!
Pallid bats (Antrozous pallidus) have frequently used this night roost on a cabin next to the East Branch of East Weaver Creek. [Mike Dixon, Bureau of Reclamation]
Hoary bat
Hoary bats (Lasiurus cinereus) are striking in appearance. Rather than the shades of brown with which bats are often portrayed, the hoary bat has dark fir with brightly frosted tips and a yellowish face. Also unlike many bats of the temperature regions, it doesn’t hibernate – rather, it spends its summers from the northern U.S. (including northern California) well into Canada, and then in the fall migrates sometimes over 2,000 km south to a winter range that extends from the Southwest into Central America (Cryan et al 2004).
A hoary bat (Lasiurus cinereus) roosting on the branch of a tree. [Paul Cryan USGS]
Rather than flying low over the water or ground or on the edges of forest, the hoary bat is a high-flying moth specialist that makes long passes over open water or the top of the forest canopy, sometimes flying almost 25 miles in a night of hunting. The coevolution of bats and moths has been a subject of long study, as there is evidence that echolocation by moth-hunting bats drove the evolution of ears and evasive behaviors in moths, which in turn changed how moth-specialist bats echolocate (Ter Hofstede and Ratcliffe 2016).
Hoary bats are more solitary than most of our bats and tend to roost individually by hanging from tree branches like dead leaves, but they can form large aggregations around landmarks during their long southward migrations. This means that after they leave our Klamath Mountains, they are often recorded in what would seem to be pretty unusual places for a bat – they have been observed swarming ships at sea and commonly recorded over the Farallon Islands 30 miles off the coast of San Francisco. These long, sometimes over-water migrations also presumably led to one of the more unlikely events in the history of bats – the colonization of the Hawaiian Islands over 1.3 million years ago by hoary bats from what is now the west coast of the U.S. In this single founder event, wayward bats established the most isolated bat population in the world, which has since diverged significantly into its own species, the critically endangered Hawaiian hoary bat (Lasiurus semotus).
Bats and people
I have already mentioned how a couple of our native bats benefit people by controlling pests, and that topic has been the subject of many publications. Suffice it to say, bats are very important to the ecology of the Trinity River watershed and provide services to its people here and throughout the world, but they can also be inconvenient and, occasionally, dangerous to people. Here are a few suggestions for living with bats.
First and foremost – while bats don’t “carry” rabies (it is also deadly to them), the abnormal behavior of rabid bats is what often brings them into contact with people. NEVER pick up a bat that you encounter. It is unlikely that it has rabies, but the consequences of contracting rabies are so serious that it is not worth the risk. If you encounter a bat in your house, shoo it out but do not handle if it all avoidable – you’d be surprised how thick of a glove a bat can bite through!
If you have the space for it, embrace an untidy yard. Long grass provides a home for large insects like crickets that are preyed upon by our gleaning bats. Leaving fall leaves until the following spring allows many types of caterpillars and beetle grubs to use them as winter cover, providing food for our aerial insectivores the following summer. Trees with loose bark cavities or large are used by many species for roosting and can be left as habitat where they do not cause a hazard.
Many species like to use buildings for day or night roosts or for hibernation. Sometimes this isn’t a huge deal – I already mentioned that I appreciate the night roost above a seldom-used door at my house, and even use their guano as a garden amendment. However, in confined spaces like the walls and attics of buildings, the guano can become smelly and damage walls, and bats roosting in those places sometimes find their way into parts of those buildings with people (not a good thing, as already discussed). Many pest control companies have experience with excluding bats in a humane way (essentially letting them fly out but not back in). If you need bats evicted from your home, try to wait until late summer when the pups have fledged, so as not to separate foraging mothers from their flightless pups.
If you’d like to encourage bats to use your property, you can build or buy prefabricated bat houses. The trick in a climate like that of the Trinity watershed with sometimes intensely hot days and cool nights is to find the right sun exposure. Nursing mothers and pups want a spot that will gather and retain heat into the evening but will not get so hot during the day as to be uninhabitable. There’s an element of trial and error (and luck) to getting bats to move in, but it’s a great way to provide wildlife habitat and help keep your bugs down. For more resources on gardening and bat houses, this is a great place to start: Bat Gardens & Houses – Bat Conservation International.
References
Baker, Michael D., Michael J. Lacki, Greg A. Falxa, P. Lee Droppelman, Ryan A. Slack, and Scott A. Slankard “Habitat Use of Pallid Bats in Coniferous Forests of Northern California,” Northwest Science 82(4), 269-275, (1 September 2008).
Dixon, Michael D. “Relationship between land cover and insectivorous bat activity in an urban landscape.” Urban Ecosystems 15 (2012): 683-695.
Ormsbee, Patricia C., James D. Kiser, and Stuart I. Perlmeter. 2007. Importance of night roosts to the ecology of bats in Michael J. Lacki, John P. Hayes, and Allen Kurta, eds. Bats in Forests – Conservation and Management. The John Hopkins University Press: pp 129-151.
Pierson, Elizabeth D. and William E. Rainey. 2007. Bat distribution in the forested region of Northwestern California. Report for California Department of Fish & Game, Contract #FG-5123-WM.
Reiss, Karen, Michael Kauffman, and Chris Feldman. Mammals in Michael Kauffman and Justin Garwood, eds. (2022). The Klamath Mountains – A Natural History. Backcountry Press. Pp. 428-430.
Ter Hofstede, Hannah M., and John M. Ratcliffe. “Evolutionary escalation: the bat–moth arms race.” Journal of Experimental Biology 219.11 (2016): 1589-1602.
Mike Dixon is the Executive Director of the Trinity River Restoration Program and a northern California native. He fell in love with the Trinity River and Klamath Mountains while assigned to his first duty station at Coast Guard Air Station Humboldt Bay. He received a Ph.D. in Conservation Biology from the University of Minnesota, Twin Cities, where his dissertation focused on the landscape ecology and population genetics of bats. He lives on a small, perennial tributary of the Trinity River near Weaverville.
Photo: The [much younger] author with a little brown bat in Voyageurs National Park
The northwestern pond turtle (Actinemys marmorata) has lived in the waters of the Trinity River for thousands of years. This species has undergone several taxonomic revisions since first being first described in 1841 (1, 2, 3). It was originally considered a single species with the southwestern pond turtle (Actinemys pallida) and called ‘Emys marmorata’. Then both species were renamed ‘Clemmys marmorata’. The northwestern and southwestern groups were more recently split into two species based on genetic and physical differences between them. So, you may read our local turtles described with different common and scientific names depending on when the document was published (3). But no matter when it was published, there is only one native freshwater turtle known to the Klamath Mountains and the current name is “northwestern pond turtle” (Actinemys marmorata).
Photo: A female northwestern pond turtle. [Don Ashton]
Actinemysmarmorata
actin = ray or beam // emys = turtle // marmorata = marbled
As its common name suggests, the northwestern pond turtle is known to inhabit ponds and lakes, but within the Klamath Mountain ecosystem they are commonly associated with riverine habitats. Northwestern pond turtles are poikilothermic, meaning that they regulate their temperature by basking in the sun when they are cold, and seek cool water or shade when they are too warm. They distribute in sunny, slow water reaches with boulder lined pools that, importantly, have connectivity to broad floodplain habitat (5, p. 353).
A male Northwestern Pond Turtle in underwater refugia on the Southfork Trinity River. [Don Ashton]
The northwestern pond turtle has an acute sense of sight and low-frequency hearing, and while they are often seen basking in the sun above water, they will quickly retreat when they feel threatened (5). Reader, a river enthusiast we surmise, we are sure you’ve witnessed the sound of a plopping western pond turtle off a river log – but did you see them?
Male turtles are known to migrate from river to upland areas to overwinter in riparian shrubs or leaf litter. This trait is not ubiquitous among all turtles as some choose to stay close to their summer habitat by overwintering in banks near the river or pond. Local herpetologist Don Ashton of McBain Associates/Riverbend Sciences has spent decades studying turtles in the Trinity River and said, “Turtles are very smart animals, they tend to migrate close to the high water line (think 100 year floodplain) but over time we have found that in comparison with North Fork Trinity River populations, turtles on the mainstem are found more frequently hibernating and nesting in lower elevation areas, likely due to adaptation of minimized flooding by Trinity and Lewiston Dams.”
In addition to migration for hibernation and summering, female turtles migrate twice for nesting. When they are ready to lay their eggs, they fill their bladders and set off on a slow but steady journey to upland areas to dig their nests. Once in a satisfactory location, the female turtle wets the ground with her urine to help soften it for digging. Once her eggs are laid, she will journey back to her summer habitat.
A Northwestern pond turtle nest, predated. Egg fragments and plug are identified. [Don Ashton]
Migration to upland areas for nesting or hibernation can often lead to chance encounters with humans or their vehicles. If you happen to cross paths with a turtle, Ashton advises to leave them to their journey, “they are not lost” Ashton declares. However, if their location poses a risk of vehicular homicide, and you feel compelled to move them, point them in the direction of their path. That is unless the turtle happens to urinate while being handled, then, Ashton suggests, they should be pointed back toward a water source.
These ancient creatures are small to medium in size, growing up to 8 inches long. Interestingly, Trinity River turtles have been documented as even smaller than their regional counterparts. Some herpetologists surmise this could be due to temperature suppression caused by elevated dam releases causing cold water releases in the latter spring and summer months (6). Watch Don Ashton’s 2024 Trinity River Restoration Program Science Symposium presentation on the subject below.
Don Ashton, Senior Aquatic Herpetologist/Ecologist for McBain Associates/Applied River Sciences presents, “Frogs and Turtles informing flow management and river restoration.” at the 2024 Trinity River Restoration Program Science Symposium.
Their dark brown or olive-colored shells often feature fine, lighter markings that give them a marbled look as reflected in their species name, marmorata. Their low profile and coloring help them blend in with riverbanks, keeping them safe from predators like raccoons, skunks, and birds of prey. The male northwestern pond turtle can be identified with a pointier snout and lighter pale cream coloring under its neck. If you encounter a turtle with hints of red near the ear it is likely a non-invasive red-eared slider, make note of where you are and if possible, provide photo documentation to the Trinity River Restoration Program or the California Department of Fish and Wildlife. Documentation of these instances can help in protecting our native turtle populations.
A female northwestern pond turtle on the Southfork Trinity River. [Garth Hodgson, Don Ashton]Adult male northwestern pond turtle. [Don Ashton]A red-eared slider. [wikimedia commons]
Unlike many reptiles, northwestern pond turtles grow slowly. They start out about the size of a quarter. Females don’t start laying eggs until they’re between 8-10 years old (3, 7, 8). They lay between 3 and 13 eggs, which incubate through the summer. In some parts of Northern California, hatchlings stay in the nest through winter, emerging the following spring. In the photo you can see a comparison of a female turtle at 55 years old with a newly hatched turtle. Ashton, in the background mentioned that the elder at age 55 was carrying 9 eggs at the time of that photo (2018) which suggests their lifespan may be quite long. Ashton mentioned, “it is certainly possible that there are turtles living in the mainstem that have lived there since before the dam was placed.”
Photo: A female, marked and recaptured and aged at 55 years old in comparison with a hatchling. Held by Bruce Bury and Don Ashton smiles from the back in 2018. [Jamie Bettaso]
The northwestern pond turtle has been studied locally for over 50 years due to the diligence of herpetologist Bruce Bury, now retired from USGS, who monitored northwestern pond turtles starting in 1968 while earning his Ph.D. at UC Berkeley. He marked turtles with an identifying notch in a tributary of the South Fork Trinity River, allowing for scientists to track longevity on the only native species known in the Klamath Range (5, p. 354). Although Bury has documented turtles over 50 years old, northwestern pond turtle longevity is still being studied today.
The northwestern pond turtle is commonly seen in the Trinity River, but its population has been declining throughout its west coast range. This decline is so severe that in 2023 the U.S. Fish and Wildlife Service proposed to list the northwestern pond turtle as a “Threatened” species (8, 11). Habitat loss, hydrologic alterations and invasive species are a few human caused threats to northwestern pond turtles. The state of California also recognizes the northwestern pond turtle as a species of “special concern”. As such, handling these turtles requires permitting and are considered illegal to keep as pets.
The Trinity River Restoration Program has been involved in research to identify and address some of these threats. A graduate student from Cal Poly Humboldt, Leah Sloan, determined that non-native bullfrogs (Lithobates catesbeianus) eat young northwestern pond turtle hatchlings to the detriment of their populations along the Trinity River (10). Bullfrogs prefer off-channel ponds, which are perfect areas for northwestern pond turtles to grow. Bullfrogs require perennial ponds to reproduce because their tadpoles take longer than one year to grow (and the mainstem Trinity River is too cold and swift to support bullfrogs year-round), so ponds that normally dry out won’t support bullfrogs permanently. Seasonal drying isn’t much of a concern to turtles because they can simply walk to the river when their home dries up. This is one recommendation for the Program to consider when rehabilitating a site.
A trail camera captures a female northwestern pond turtle basking on a log. [Don Ashton]
Today, turtle researchers and wildlife managers are still learning more about turtle behaviors and how to change management to better serve the northwestern pond turtle in the Trinity River region. From size and aging to nesting sites and travel patterns, each discovery helps build a clearer picture of what these turtles need to thrive.
Cattails may be one of the most familiar sedges with its endearing name and inflorescence (or flower), which looks like a corn dog perennially sticking out of the tall green walls of a marsh. However, the cattail’s cousin, tule (also referred to as bull-rush) occupies similar habitat yet is not able to persist in the languishing habitat conditions that emergent wetlands undergo today.
The world’s center of diversity for cattail is in Eurasia with 6 species found on every subcontinent. North America also has several different species (9 in North America) including 2 species native to California. Additionally, there are several species from the Eurasian subcontinent that can be found in North America, including locally, which have been shown to exhibit invasive behavior.
The most common species of cattail is Typha latifolia and the most common species of tule or bull-rush is Schoenoplectus acutus. Schoenoplectus or tule are represented by 25 species, 15 of which are on the North American subcontinent, and 9 of which are native to Californian wetlands. Schoenoplectus californicus and S. acutus are the large stature tule common in Trinity County.
Cattail and tule are both around the same ‘stature’ or blade height which represents the overall plant height, however there are several ways to tell the two apart.
Typha species botanical illustration in Flora of North America by John Myers.Tule species botanical illustration in Flora of North America by John Myers.
Cattail has a wide flat blade that is arranged in a ‘fan’ like an iris. Looking at the leaves alone one might think that this species is an Iris. Tule has a round hollow leaf, not flat at all, which is unusual for a sedge! The typical saying for sedges is: “sedges have edges” and “rushes are round” but tule breaks this rule.
CalFlora Typha latifolia. Ron Vanderhoff CC-BY-NC 4.0Tule leaves are round and hollow. [Simone Groves, Hoopa Valley Tribal Fisheries]
Also, the flowers of the plants look very different. With cattail, it’s common name is descriptive of the flower. In many sedge species, there is a male flower at the top of the inflorescence, and female at the bottom. The fluffy stuff that you’re used to seeing on a cattail is actually the seeds! Each has a separate wind-blown umbrella to help it land far away from the mother plant. Sometimes it can take a full rotation from fall to spring before the seeds will release from the corn-dog flower head, which can coincide with the nesting period for many birds. Cattail seeds are not very nutrient dense, but you might find birds harvesting beaks full of fluff to line their nests.
CalFlora Typha latifolia. Ron Vanderhoff CC-BY-NC 4.0Schoenoplectus acutus at the Humboldt Bay National Wildlife Refuge
In tule, the seeds are born in a little toss of beads on the end of a string which emerges from the top of the tall, round leaf stalks. Tule seeds (in contrast to cattail seeds) are desirable as bird food, and songbirds in the marsh can often be found hanging crookedly off a tule leaf and eating the ornament of seeds from the top of the plant.
Typha_latifolia with Equisetum. [E. Makings, ASU Vascular Plant Herbarium]Tule in a slow water area. [Simone Groves, Hoopa Valley Tribal Fisheries]
These plants both require slow-water habitat. Cattail can handle wider extremes of environmental conditions, such as more scour, a higher tolerance of both inundation and dryness, and a greater ability to establish from windblown seeds.
Tule on the other hand, requires backwater areas with very little scour, specific amounts of perennial inundation and cannot usually tolerate completely dry conditions (6). Oxygen is often the limiting factor for primary productivity in hydric wetland soils. This suggests that when tule experiences good growing conditions, it can facilitate survival of other oxygen-dependent species (which is typically considered more desirable for diversity in aquatic environments). Tule and cattail are often competitive bedmates and cattail will usually win the inexorable struggle when the two spar for habitat.
The Latin derivative for cattail, Typha, may come from the Greek word typhein, to smoke or to emit smoke; or typhe meaning “cat’s tail” but the true reason for using this Greek root is not known today. Some resources today often find these descriptions to be confusing because it is hard to understand why this plant might be described as ‘smoke’ unless one has a relationship between fire and wetland communities, and so, many people call it cattail because either interpretation could be an explanation for its name. This plant language offers us an opportunity to be curious and listen to others to unravel the answer.
A close up of cattail seeds. [Steve Matson]
Historically California tribes have an intimate relationship to wetland habitats. Many tribes will refer to the wetland as the “medicine cabinet” or “drugstore” as many species foundational to healthy living within ecosystems can be found in these habitats. Additionally, in California, burning would be carried out in wetland communities to help maintain the health of the tule and maintain the balance of this critical habitat for both ecosystem function and human health (9, 11, 12, 13).
European history documents cattail flower heads utilized as slow burning torches that were very smoky and may have helped to repel insects. Also, many historical references to “reed” are referring to cattail, including biblical references (21).
In local languages, the Hupa people describe tule as tł’ohtse’ (17). Karuk people describe tule as taprarahtunvêech for living plants or taprárah for the plant in use as a mat or sewn object (18). Yurok people describe tule and cattail synonymously as ‘wehlkoh meaning “leaves woven together to make a mat or raincoat” (24).
In plain English, cattail can also be called “bull rush” which leads us back to the reason why these two species are paired together in this article! How can we tell which “bull rush” is the true bull rush?! One of the great struggles with plants is the ability to communicate effectively about which individual is being described from person-to-person. This is a challenge that has been handed down through many generations and has led us to the current era of the California Jepson Manual and using dichotomous keys and Latin to separate different plant descriptions from one another. For this reason, the term “bull rush” or “rush” can be an ambiguous description, but for this article it is important to create distinction.
The fossil record of cattail can be traced back to the Paleogene part of the Cenozoic, which is when non-avian dinosaurs went extinct. This era is marked in the geologic record by the iridium anomaly along with the deposition of several other transition metals which can be toxic for animal consumption. This was at the same time as mammalian and vertebrate diversity expanded dramatically and the circumpolar current began to form. Both cattail and tule can bio-accumulate toxic minerals and provide filtration for slow water habitats. One can imagine how this may have supported survival of new life in a stressful environment (23).
Both humans and animals have a long history of using cattail and tule. All parts of both of these plants are edible at various life-history stages (10, 14, 15). The roots of both plants are thick and starchy and have been harvested, cultivated and tended by ancient humans before agricultural practices began. The mashed-up starch can also be used to staunch bleeding and disinfect wounds.
Cattail shoots are usually harvested when young. They look and feel like a leek and have a similar texture when cooked, with a milder flavor. The pollen is high in protein and can be used like flour to thicken soups or make pancakes. Stems of cattail can be made into a tea to treat whooping cough (16). The fluffy seeds of cattail have been used as diapers, sanitary napkins and for dressing wounds by humankind worldwide with it’s soft absorptive features.
Tule’s young shoots can be eaten like asparagus but mature leaves can act as an emetic, causing vomiting. Tule’s most famous use is for fiber. Many tribes throughout California in particular have used tule leaves for houses, weaving sleeping mats and roofing for houses as well as tule boats (22).
Tule and cattails provide very important habitat for birds in particular. Beyond a source of sustenance, wetland birds also use these habitats for the edge effect that they create for protection. The aerial friction that these plants provide, creates a buffer from extreme weather conditions within the boundary layer of a wetland, which is typically a pretty exposed environment. Both of these species can be used in botanical wetland delineation to establish protected habitats (23).
Both cattail (Typha latifolia) and tule (Schoenoplectus acutus) play vital roles in the ecology of wetland environments, serving not only as crucial habitats for various wildlife but also as important resources for human communities throughout history. Their unique characteristics, from the distinct morphology of their leaves to their varied reproductive strategies, highlight the biodiversity present within these ecosystems. Furthermore, understanding their ecological functions and cultural significance can foster greater appreciation and stewardship of wetlands – a critically important yet declining habitat area within our watersheds.
Simone Groves, Riparian Ecologist, Hoopa Valley Tribal Fisheries
Simone is first generation California transplant of scottish descent raised in the unceded territories of the Raymatush in the rural west peninsula of the SF Bay where farmers, farm workers and hippies form the heart of the small town. She graduated in 2016 from Humboldt State University with a BS in Botany and has worked in the outskirts of rural Humboldt county on Natural Resource and Land management since 2013. She is passionate about plants and their interactions with dynamic systems as a mechanism for relearning our human-landscape interdependence.
Federal funding has provided the opportunity to institute much-needed modernization for the Trinity River Hatchery. Trinity River Hatchery (TRH) is a Reclamation-owned, Central Valley Project mitigation hatchery which was established to produce juvenile salmonids to mitigate for the loss of fish habitat upstream of Lewiston and Trinity Dams. Both dams are integral components of the Trinity River Division of the Central Valley Project. Reclamation owns the Trinity River Hatchery and the associated lands. Reclamation’s Northern California Area Office has funded the California Department of Fish and Wildlife to operate and maintain the Trinity River Hatchery since the hatchery’s construction in 1963. Additional support for Trinity River Hatchery operations comes from the Hoopa Valley and Yurok Tribes.
One of the juvenile raceways at TRH. [Bureau of Reclamation]
Currently, the hatchery’s annual goal is to produce approximately 5 million juvenile salmonids. The Trinity River Hatchery produces spring run Chinook Salmon, fall run Chinook Salmon, steelhead, and the federally threatened Coho Salmon. These species are highly significant for economic, recreational, and cultural values of the region. Trinity River Hatchery produced fish support tribal, recreational, and commercial fisheries in the Klamath River, Trinity River, and Pacific Ocean. Additionally, Trinity River Hatchery is an important and notable location for Trinity County and Northern California, receiving thousands of local visitors, school groups, and tourists, annually.
After 60 years of continual use, Trinity River Hatchery infrastructure has become antiquated, fallen into disrepair, and/or has passed its expected operational life. These issues have led to inefficiency in water use (e.g., broken valves that cannot be shut), outdated aquaculture infrastructure (e.g., limited adult holding capacity), and personal health and safety concerns (e.g., sink holes). Issues with the water supply regulation, for instance, introduce risks to fish production, fish health, and the ability to safely maintain and efficiently operate infrastructure. These problems are compounded by the new requirements for hatchery operations under two Biological Opinions (WCR-2018-9118 and WCRO-2019-0414) and a Coho Salmon Hatchery Genetics Management Plan. The current hatchery configuration and components make implementation of these legal requirements difficult. Trinity River Hatchery does not have the space and facilities to meet the needs of these new legal requirements (e.g., lack of adult broodstock holding space). Modernization is needed to address current facility short falls and bring contemporary aquaculture components to Trinity River Hatchery.
The Northern California Area Office initiated a project to fully review Trinity River Hatchery infrastructure through a third-party consultant. In 2022, the Trinity River Hatchery Infrastructure Review and Alternatives Analysis was completed. The report detailed the current condition of the facility and its systems, evaluated the current and future production goals, identified cost effective and programmatically viable infrastructure alternatives, assessed the biological and environmental risks associated with these alternatives, and provided cost estimates for the alternatives. This report was used as the basis (i.e., feasibility study/appraisal report) for Northern California Area Office’s Bipartisan Infrastructure Law (BIL) application. The estimated cost for implementing the preferred alternatives was $65.9 million.
In early 2023, it was announced that the Bipartisan Infrastructure Law – Infrastructure Investment and Jobs Act (IIJA) would provide funding to modernize the Trinity River Hatchery. Through the IIJA, Reclamation looks to repair, upgrade, and/or rebuild Trinity River Hatchery infrastructure systems to meet the needs of modern aquaculture practices and technology. Major infrastructure systems that require modernization include the water intake, water treatment, water distribution, hatchery building, adult holding ponds, spawning building, effluent treatment facilities, office space, and maintenance buildings, along with many other components. A full list of key areas for modernization can be found in the Trinity River Hatchery Infrastructure Review and Alternatives Analysis document (Four Peaks Environmental 2022).
Once funding is secured, Northern California Area Office will begin working on developing permits and environmental compliance documents, seek the services of a qualified architecture and engineering firm for design, and plan for construction. Throughout the project, Northern California Area Office intends to work with our partner agencies and tribes, via a technical team. This large-scale project will take several years to complete.
Key Document Four Peaks Environmental. 2022. Trinity River Fish Hatchery Infrastructure Review and Alternatives Analysis. Prepared for U.S. Bureau of Reclamation.
Fish Biologists Turned Farmers: Growing Food for Juvenile Salmonids in a Regulated River System
Scientists measure flow at a benthic macroinvertebrate sample site on the Trinity River this March. [Kiana Abel, Trinity River Restoration Program]
Modern river science related to salmon restoration is everchanging due to the complex interplay of factors affecting their life cycle. There are man-made issues including habitat degradation, barriers to migration, harvest; as well as environmental, such as climate change, and ocean conditions. This makes it difficult to isolate and address specific issues as they are all interconnected. There is also intricacy in finding patterns to mimic regarding the complexity of change that our system presents us from year to year (think wet year vs dry year).
For many years river restorationists followed the mantra of “if you build it, they will come” thus resulting in habitat reconstruction efforts along identified areas within the 40-mile Trinity River Restoration Reach. This combined with increased releases from Lewiston Dam (starting in the year 2004) are thought to have led to the doubling of natural origin juvenile Chinook Salmon populations in the Trinity River (Pinnix et al 2022).
Even though we have seen a doubling of juvenile Chinook Salmon outmigrants from the Trinity River, adult returns remain lower than in the past. A decline of adult Chinook Salmon returns along the entire West Coast indicates there may be other issues than just in the rivers alone. Chinook Salmon have many limiting factors to survival and the Program can significantly influence only a portion of the Chinook Salmon’s life history – the riverine stages (returning adults to juvenile outmigration). Trinity River ecologists have been evaluating changes to restoration techniques to understand how to produce more robust juvenile salmon, and hopefully more returning adults, within the limited area and timeframe they inhabit the mainstem Trinity River.
One clue from decades long data collection is that the juveniles, although more in quantity, are smaller now than in the past– leading to the indication that growth rates might be inhibited during their rearing period. This indication has led program scientists to conduct a multi-year monitoring effort aimed at shedding a more definitive light on how food sources for juvenile salmonids interact with flow, temperature, scouring floods, and floodplain inundation on the Trinity River.
Until recent management changes, Lewiston Dam, was not managed to release variable flows that mimicked pre dam flows during the winter months. The lack of variation and flow has prevented several ecological processes, like scouring floods and floodplain inundation, and these seasonal floods build and break down algae which feed benthic macroinvertebrate communities which are the food supply for young salmon when they hatch and emerge from gravels.
Read on to explore the significance of algae, and the fish food within (benthic macroinvertebrates) alongside key functions of scour and inundation and how these important functions build the foodscape to aid juvenile salmonids within the Trinity River.
Trinity River Juvenile Salmonids
Juvenile Chinook Salmon. [Ken DeCamp]
Salmonids are a keystone species meaning their presence and activity have a disproportionately large impact on their ecosystem. Juveniles specifically play a crucial role in ecosystem health by serving as food for various predators in the river system, including other fish, birds, and mammals. As they grow into adults salmon are critical to support recreational, commercial and Tribal harvest as well as delivering important marine derived nutrients from the ocean back to inland ecosystems.
Trinity River salmonids that are native to our watershed each have unique life histories as well as habitat needs within the river system. Due to their cultural, economic and environmental influence the three native species of interest to the Program are Steelhead (Oncorhynchus mykiss), Coho Salmon (O. kisutch), and Chinook Salmon (O. tshawytscha). There are also two additional native anadromous species to the Trinity that have specific cultural and ecological significance; the Pacific Lamprey (Entosphenus tridentatus) and the Green Sturgeon (Acipenser medirostris).
Despite unique habitat needs these species do share common life-history requirements that are considered when making decisions regarding restoration of the fisheries. At the juvenile stage these requirements include;
Sediment vital in just the right amount. Spawning gravel that has a low amount of fine sediment helps water flow through the spaces between the eggs, which increases the chances of eggs hatching and young fish survival. However, too much sand and silt can suffocate both the eggs and fry, making it harder for the young fish to emerge successfully.
Diversity in temperature and flow. When digesting they require low-velocity, shallow habitats that provide temperatures for prime digestion. As they grow, a variety of habitat types are required that include faster, deeper water and instream cover;
Overwintering habitat. Coho salmon and steelhead must have abundant overwintering habitat composed of low-velocity pools and interstitial cobble spaces; and
Food availability. abundant food sources can increase their chances of survival during their migration to the ocean and ultimately, as adults, to return to spawn.
Regulated river systems, shaped by dams, levees, and other infrastructure, significantly disrupt the natural processes that support juvenile salmonids. Most significantly, habitat availability below a dam is limited by the loss of natural processes of rivers. Thus, the Program has been given five main tools to mitigate for the presence of the dam. Flow Management, Channel Rehabilitation, Sediment & Wood Augmentation, Watershed Restoration, and finally Adaptive Management.
The Trinity River Restoration Program utilizes channel rehabilitation to return low floodplain habitat to the river and its aquatic species. In recent rehabilitation projects like Oregon Gulch, the designs are intended to follow the Stage 0 restoration concept. Stage 0 restoration is a method for restoring rivers that focuses on resetting the river to allow natural processes to shape the landscape. The goal is to recreate environments where river processes can improve connections within the ecosystem. This approach helps create vibrant and self-regulating riparian and stream areas that can develop on their own over time.
The Program also utilizes variable flow management to help shape habitat. Until recently due to forecast methods and limited data, variability was only utilized during one season, the snow-melt peak and recession period (April through June, July and in wetter years into August). In water years 2023 and 2025 Program partners came to agreement that changing variability by reallocating water to key growth periods during the late winter and early spring months could help juvenile salmon become more robust.
Scour and Inundation: Key to River Function in Mediterranean River Systems
Scouring floods and floodplain inundation are two important river processes influenced by river releases. Scour and inundation’s ability to support young salmon rely heavily on the physical structure of the Trinity River.
Dr. Eric Peterson, Science Coordinator for the Trinity River Restoration Program, talks about the important ecological function of scour. Scour is a process in river systems that builds a rivers shape by rolling rocks and resets algae and bug populations.
Scour occurs during large winter storms when fast-moving water erodes the riverbed, moving sediments and changing the channel’s structure. This process helps to maintain river functions by exposing and transporting sediments, logs, and nutrients throughout the river system. Combined with flow, these elements contribute to a dynamic river design and are crucial for all life stages of salmon. Logs and sticks create hiding spots from predators and provide areas with optimal flow conditions for feeding. Deep scoured holes provide temperature diversity throughout the year. The movement of sediments and other detritus transfer nutrients to floodplains which provides a suitable substrate for algae and benthic-macroinvertebrate populations.
Chris Laskodi, Fish Biologist for the Yurok Tribe discusses the ecological function of inundation and drift for young salmon and the foods they eat during the winter months when rivers are swollen with water.
Inundation refers to the seasonal flooding of riverbanks and adjacent floodplain habitats during higher flows during the spring. This flooding is vital for rejuvenating riparian zones and promoting the growth of riparian vegetation. Inundated areas often serve as nurseries for juvenile salmonids, providing preferred temperatures for digestion and shelter from faster areas of higher flow within the main channel. The nutrients deposited during flooding can enhance algal and macroinvertebrate production, further supporting the growth of juvenile salmonids.
The Role of Algae & Benthic Macro Invertebrates in Juvenile Salmonid Success
Algae play a significant role in primary productivity, providing essential food sources for various aquatic organisms, including benthic macroinvertebrates, the favored food of out-migrating juvenile salmonids. Through photosynthesis, algae contribute to oxygen production, an essential requirement for many aquatic species. Additionally, algae facilitate nutrient cycling within the ecosystem helping to enhance habitat health.
Benthic macroinvertebrates are tiny invertebrates that live on the riverbed. While young salmon feed on both terrestrial and aquatic invertebrates, these organisms provide an essential source of food for juvenile salmonids. Common examples of benthic macroinvertebrates that juvenile salmon consume include mayflies, stoneflies, midges, and caddisflies. Moreover, these organisms serve as indicators of ecosystem health; their presence, diversity, and abundance can offer valuable insights into the ecological status of a river system. In addition to being food for juvenile fish, benthic macroinvertebrates contribute to the breakdown of organic matter, aiding nutrient cycling and improving overall ecosystem productivity.
Understanding the roles of algae, benthic macroinvertebrates, scour, and inundation in the Trinity River, a regulated river system, is essential for supporting juvenile salmonids. By recognizing the interconnectedness of these organisms and processes, ecologists can implement strategies that potentially promote a balanced ecosystem. Ensuring that algae and macroinvertebrate populations meet the demand of juvenile salmonids will enhance their health and survival contributing to the overall vitality of aquatic ecosystems.
