New techniques for modeling water temperatures have allowed U.S. Geological Survey (USGS) scientists to better predict how climate change will affect the habitat of fish species like brook trout, according to a recent study.
Climate change is expected to bring warmer air temperatures to the Chesapeake region over the next several decades. And as air temperatures rise, water temperatures will also increase, threatening fish species like brook trout that are particularly sensitive to warming waters. Previous modeling has assumed water temperatures in rivers and streams would rise in a uniform manner, failing to account for the effect that cool groundwater has on warmer surface water.
“One thing that has been missing from other models is the recognition that groundwater moderates the temperature of headwater streams," said Nathaniel Hitt, coauthor of the study. "Our paper helps to bring the effects of groundwater into climate change forecasts for fish habitat." Accounting for the effects of groundwater will allow for better predictions of brook trout habitat loss, as well as more targeted approaches for habitat protection.
Species like brook trout are an essential part of headwater stream ecosystems, an important part of the watershed’s heritage and a valuable recreation resource. Chesapeake Bay Program partners committed to restoring and sustaining brook trout populations as part of the Chesapeake Bay Watershed Agreement.
The article, “Accounting for groundwater in stream fish thermal habitat responses to climate change,” is available online.
In rural West Virginia, a fisherman casts his bright green line into a mountain stream. The stream is clear, the fish are biting and it takes just minutes to make a catch.
Dustin Wichterman, Potomac Headwaters Project Coordinator with Trout Unlimited, dips his net into the water and reveals a 10-inch brook trout. Its olive green body is flecked with red and gold, and its mere presence here is a welcome sign of health for the Pendleton County waterway.
Native to the headwaters of the Chesapeake Bay, the eastern brook trout is a sensitive species that needs cold, clean water to survive. But as regional water quality has declined, so, too, have brook trout populations, leading to lost revenue and diminished fishing opportunities for headwater states.
Brook trout play a critical role in the watershed: they are an important part of the region’s natural heritage, a driver of economic growth and an indicator of environmental health. For these reasons, brook trout restoration was a listed outcome in the federal Strategy for Protecting and Restoring the Bay Watershed. And for the past two years, brook trout conservation has been a top goal for the Chesapeake Bay Program.
Through the Bay Program’s Habitat Goal Implementation Team, whose members work to protect and restore wetlands, woods and other habitats across the watershed, brook trout have benefited from stream restoration, fish passage renewal and tree plantings.
As odd as it might seem, the health of a fish depends not just on the health of the creek, stream or river that it calls home; it is also tied to the health of the surrounding land. And poor land management, increasing development and expanding urbanization have been cited as leading factors in brook trout decline.
“This fish is a living symbol of how actions on land affect the health of our local waterways,” said team coordinator Jennifer Greiner.
The removal of streamside trees, for instance, is a common consequence of agricultural or residential development, as seedlings are trampled by grazing cattle or trees are felled for suburban growth. But a missing forest buffer means bad news for brook trout when stream banks erode, excess sediment ruins spawning beds and an absence of shade pushes water temperatures into a range that brook trout cannot withstand.
When, on the other hand, trees and shrubs are allowed to grow along waterways, their runoff-trapping roots keep the water clean and their shade-producing leaves keep the water cold.
So Greiner and her fellow team members have worked to bring brook trout into the land-use discussion, pushing the latest brook trout distribution data out to doers and decision-makers in the watershed. Because when land managers know where brook trout are, they are more likely to take the fish into account in land-use decisions.
Land trusts in headwater states have also found that brook trout can push private landowners to conserve, and Goal Implementation Team partners—the U.S. Fish and Wildlife Service, the Natural Resources Conservation Service, the National Fish and Wildlife Foundation and the Eastern Brook Trout Joint Venture Partnership among them—are using the iconic fish to promote on-the-ground restoration of riparian forest buffers.
Whether a farmer installs a fence that keeps livestock out of local rivers or a landowner decides to plant a series of streamside trees, education and engagement are critical to conservation.
“By becoming educated and engaged, landowners are able to protect the streams on their land for future generations,” Greiner said. “By protecting and restoring stream habitat, the brook trout, along with other species, are also protected for future generations to enjoy.”
“The smallest ripples are often the largest fish,” Matt Sell tells me as he waves his fishing line back and forth over a dimple in the water. The scene may seem appropriate for a Saturday afternoon, but it’s actually a Wednesday morning, and Matt is at work as a brook trout specialist for the Maryland Department of Natural Resources’ (DNR) Inland Fisheries Division.
Clad in chest waders and a t-shirt, Matt is armed with a fishing pole and the instincts of someone who’s been angling most of his life. His fishing efforts are rewarded with a 6-inch brook trout – exactly the species he was looking to catch.
In most parts of the state, a brook trout would be a rare catch. More than 55 percent of Maryland’s sub-watersheds have lost their entire brook trout population, and only 2 percent of the state’s sub-watersheds have a healthy population.
Why the sudden and steep population decline? Brook trout have very specific habitat requirements that are threatened by development, urbanization and poor land management.
“Brook trout need cold, very clean water with no sediment,” explains Alan Heft, biologist with Maryland DNR’s Inland Fisheries Division. “They need specific sizes of gravel in certain areas of the stream to reproduce. If they don’t have these conditions, they can’t exist.”
When excess sediment erodes from stream banks and construction sites, dirt gets into the gravel beds where brook trout spawn, hardening the bottom into a concrete-like material. And when water temperatures rise above 68 degrees due to factors such as hot summers and lack of a tree canopy along the edge of a stream, a brook trout’s internal system shuts down.
“Brook trout are kind of like the canary in the coal mine,” Alan says. “When you have a large brook trout population, you know that you have good water, clean water and a protected watershed. When you lose the brook trout, you know that you have problems.”
Because brook trout have such steep habitat requirements, they are used as an indicator species: their presence indicates whether or not a watershed is healthy. By closely monitoring brook trout populations, scientists can learn not just about the fish, but about water quality in a river system.
But monitoring brook trout requires more than just fishing. Although there are many methods used to monitor the fish, Matt and Alan have chosen radio tags, which they insert into each fish’s skin through a quick, painless surgery. The radio tags allow Matt, Alan and other scientists to follow the movements of brook trout for the next year or so.
When I follow Matt and Alan on their Wednesday morning fishing excursion, they bring me to a dense forest of eastern hemlocks. Mountain laurels hug the shallow stream banks, blocking the sun and forming a blanket of shade over the river. With the lush layers of forest, the serenity of fishing and the absence of human influence, it feels as though we’ve traveled back in time. But we’re actually on western Maryland’s Savage River, a 30-mile-long tributary of the Potomac River and the largest remaining native brook trout habitat in the mid-Atlantic.
Although brook trout have been eliminated from the majority of Maryland’s waterways, these fish have remained in the Savage River for a few reasons. With just 1,500 residents, the Savage River watershed has not been subjected to the fast-paced development taking place in other parts of the Chesapeake Bay region. About 80 percent of the watershed is state-owned, meaning that the vast majority of the land around the river is safeguarded from development and managed to enhance water quality and brook trout habitat. (Plus, who wouldn’t want to live in a traffic-free, forested oasis in the Appalachian mountains?)
“Typically with brook trout habitat in the east, outside of Maine and a few places in New York, all of the tributaries are disconnected. There’s damage or dams or pollution, and they can’t go from one spot to another,” Alan explains. “But these fish can go up to 30 miles in one direction. They can go up Poplar Lick six miles; they can go down to the reservoir. It’s incredibly unique and there’s hardly anything like this left. It’s our gem.”
Sure, there’s plenty of room for the fish to travel, but Alan, Matt and others with the Eastern Brook Trout Venture want to know exactly where the Savage River’s brook trout swim throughout the seasons. “In order to answer our questions, we implemented this radio tagging study last year,” Matt tells me. “Last year, we had one fish move about three miles overnight. I had one fish that moved about four miles from where it was tagged.”
These sudden movements tell Matt and Alan that some factor encouraged the fish to move far – and fast. “It seems the impetus for these fish to leave the river in the summer months was an increase in water temperature,” Matt says. “In the winter months, they move back.”
By identifying the fish’s preferred habitats, biologists will be able to manage the land to imitate these favored spots, which will help keep the river’s brook trout population healthy.
The large-scale decline of brook trout is not due to overfishing. However, harvesting these fish certainly won’t help rebuild populations. That’s why Maryland DNR decided to create a special regulation for brook trout harvesting in sections of the Savage River watershed.
“You can fish for brook trout with an artificial lure only, and you can’t keep them,” Alan says. “The result so far has been phenomenal, for both the population and for the quality of the fishing.”
It may be difficult to understand how Matt and Alan’s brook trout restoration efforts in the Savage River – 200 miles from the shores of the Chesapeake Bay – are connected to the Bay’s health. After all, western Maryland is a far cry from the crabs, oysters and sailboats associated with the nation’s largest estuary.
“Water rolls downhill,” Matt says simply. “It has since the beginning of time and it will continue to do so. If we can protect the water quality here, as it continues to move downstream, it has a better chance as it flows on towards the Bay.”
So the restoration efforts Matt, Alan and other brook trout scientists dedicate their careers to aren’t so far removed from the Chesapeake after all. “These streams out here 200 miles from the Bay are vital,” Alan says. “When you add up all the water in these small headwater streams, it’s an amazing amount of water.”
Growing up, Carol McDaniel spent a summer or two playing in northeast Ohio’s streams. Catching salamanders and crayfish helped her develop affection for the outdoors. After working 30 years as a nurse in Baltimore, McDaniel is now reliving her childhood in western Maryland, where she monitors streams, searches for macroinvertebrates and mobilizes volunteers with the Savage River Watershed Association (SRWA).
“We were always into the outdoors even though we didn’t work outdoors,” McDaniel says. Her husband, Joe, is a retired scientific computer programmer. “When it got to the point where we were trying to retire, we wanted to pick a place that our kids would want to visit.”
The place they chose was a home on top of a ridge in the Youghiogheny River watershed. The Youghiogheny is not part of the Chesapeake Bay watershed (the “Yough” – pronounced yah-k – flows to the Mississippi River), but it borders the Savage River watershed, one of the most pristine corners of the Chesapeake region.
The Savage River watershed is the largest natural remaining native brook trout habitat in the Mid-Atlantic. Brook trout are able to live in the majority of the 30-mile-long Savage River and its tributaries because the water is highly oxygenated and stays cool (below 68 degrees) year-round. Because brook trout have such steep habitat requirements, they are used as an indicator species. More brook trout in a stream tells scientists that the water is healthy.
But the watershedmay not be healthy much longer. What McDaniel describes as the “inevitable” Marcellus Shale drilling poses a threat to the region. One spill, she says, and the brook trout would be gone.
Another constant issue is landowner habits, such as allowing cows to defecate in steams. Such actions spread beyond private property and into the river system. This problem is particularly serious in rural areas such as Garrett County, where residents may own large parcels of land.
Fortunately, residents involved with SRWA are working together to mitigate and monitor the river system. Since the organization first began (in 2006, with an ad in the local paper calling for “stream monitoring volunteers”), members have grown to include trout fishermen, professors and students at nearby Frostburg State University, part-time residents who vacation in the region, farm landowners, and interested streamside property owners. These diverse perspectives are a tremendous benefit to the organization, as input from every one of watershed's 1,500 residents is essential if the Savage River is to remain healthy.
“We're trying as an organization to walk a delicate line, and not be perceived as a radical tree hugging group,” explains Annie Bristow, SRWA treasurer. “We really want landowners to be on board and for us to be perceived as an organization that can help them.”
Most recently, a couple came to a SRWA meeting asking for the group’s assistance. Their property along the Savage River had begun to rapidly erode due the massive snowmelt during the winter of 2010. SWRA received a grant, and restoration is to begin in spring of 2013.
(Image courtesy Savage River Watershed Association)
“I try to have hope, but everyone keeps telling me that this is going to happen.” Bristow is referring to natural gas extraction from the Marcellus Shale region in western Maryland. “I guess it is inevitable.”
The Marcellus Shale is a sedimentary rock formation in the Appalachian province that contains deep underground deposits of natural gas. Its use is fairly widespread; according to USGS, in 2009, 25 percent of the energy consumed for electricity, cooking and heating the United States came from natural gas.
As the demand for affordable energy sources increases, energy companies have begun to drill through the rock to extract natural gas. Widespread concern about the environmental effects of this “fracking” process has led to regulations against it in Maryland. Although this protects Maryland's water resources, the bordering states of Pennsylvania and West Virginia have fewer natural gas drilling regulations.
“There are sections of Garrett County where there are only nine miles between Pennsylvania and West Virginia, so Maryland (in between) is still affected greatly,” explains Bristow. “There's drilling sites in West Virginia and Pennsylvania that affect our tributaries, and those streams are already being monitored.”
SRWA seeks to monitor the health of streams before drilling occurs to develop a “baseline” for post-drilling comparison. After undergoing rigorous training by the Maryland Department of Natural Resources, Bristow and McDaniel trained SRWA volunteers to measure water quality indicators such as temperature, pH and conductivity on 13 sites along the Savage River and its tributaries.
While SRWA and Maryland DNR have been monitoring streams long before the Marcellus Shale debate began, the potential effects of natural gas drilling serve as a new incentive to keep an eye on the Savage River.
“I think when they do begin drilling, we are going to see people concerned about the watershed coming out of the woodwork,” says McDaniel.
One reason the Savage River's water temperature is cool enough for brook trout is the shade provided by eastern hemlock trees along its banks. But these dense hemlock forests may not survive much longer; a tiny insect known as the hemlock woolly adelgid is sucking sap from hemlock trees and killing them. Just as SRWA is preparing for the inevitable Marcellus Shale development, volunteers are also expecting streamside hemlocks to disappear due to this invasive sap-sucker.
To avoid eroding soil, increased water temperatures and other perils that come with bare stream banks, SRWA has planted 4,000 red spruce trees along the Savage River’s shoreline. This spring, they plan to plant 500 more.
(Image courtesy Savage River Watershed Association)
If you drive on Interstate 68 into Garrett County, you'll see a number of farms, each with its own accompanying man-made pond.
“When this area was turned into farmland after it was logged at the turn of the last century, every farmer dug a pond,” explains McDaniel.
Ponds and other unshaded, open areas quickly heat up in warmer months. When these ponds are attached to the Savage River and its tributaries, they dump warm water into the system. This affects water quality, water temperature, and consequently, brook trout.
“One of the things we would like to start doing is to take these ponds off the stream at no expense to the farmer or landowner,” explains McDaniel.
SWRA supported a project that rerouted a pond belonging to the City of Frostburg. “We turned the pond into a three or four acre wetland and re-routed the stream,” says McDaniel. “Within two or three months, there were baby trout in the stream!”