Smallmouth bass, a leaping delight for anglers, continue to be hounded by mysterious disappearances, low survival rates, gaudy open sores and flood-challenged spawning seasons in the Chesapeake Bay region.Pennsylvania fishing guide Joe Raymond holds a healthy adult smallmouth bass from the Susquehanna. (Ad Crable)

At a recent summit, fisheries biologists, anglers and fishing guides from Maryland, Virginia, West Virginia and Pennsylvania came together to assess the health of smallmouths and offer theories on the elusive search for causes.

Specifically, reports were presented on the upper Potomac River in Maryland, South Fork of the Shenandoah River in Virginia, South Branch of the Potomac River in West Virginia and lower Susquehanna River in Pennsylvania.

Smallmouths, along with their cousin, largemouth bass, are the most popular game fish in North America, even more so than trout and striped bass.

Though more studies are needed, summit participants generally agreed that suppressed immune systems are harming smallmouth bass in a variety of ways. Contaminants from two main sources are compromising their ability to fend off disease: pharmaceuticals running through sewage plants as well as chemicals from pesticides, herbicides and fertilizers running off the land.

But those were far from the only concerns. There were common fears that high river flows in the spring could be the new norm, devastating bass reproduction. Flooding and strong currents can wash away spawning beds, eggs and fingerlings.

Other worries included invasive fish such as flathead catfish and snakeheads that eat and crowd out bass and forage fish, blue-green algae outbreaks and increased fishing pressure from anglers using kayaks and other small watercraft that can access more shallow areas.

Anglers and bass guides were invited to the summit to share what they have seen on the water in the various areas. For the most part, their observations meshed with what scientists have recorded.

Some had strong words. “We have a major problem on the river. It’s absolutely in decline,” said David Neuman, a bass guide from York County, PA, speaking of the Susquehanna.

“I think our rivers are being quietly polluted,” said Mark Frondorf, the Shenandoah Riverkeeper who organized the meeting. “In many respects, I just think the smallmouth bass population is sensitive to clean water. They’re kind of the canary in the coal mine in the entire mid-Atlantic.”

Vicki Blazer, a fish ecologist with the U.S. Geological Survey who has been studying the demise of smallmouth bass in the Bay region longer than anyone else, said getting to the bottom of the 15-year-old problem will not be easy.

These two healthy smallmouth bass were caught and released on the Susquehanna River in Pennsylvania. (Ad Crable)“There are a lot of things fish are being exposed to and they might get sick from if they are immune-suppressed,” Blazer said. “We want a smoking gun so we can say we want to do something about it or not do something about it and move on, but we need to move past that and take a bigger look at what is going on in the environment.”

Like many other fish now swimming in Bay waters, smallmouth bass, also known as bronzebacks and smallies among other affectionate monikers, are not native to the region. The member of the sunfish family was originally only found in upper and middle parts of the Mississippi River basin and in the Great Lakes-Saint Lawrence River system.

But as logging, mining and industrial growth polluted rivers, native brook trout disappeared. Water temperature increased and smallmouths, which live in warmer water, became the game fish of choice. Many rivers were stocked with smallmouth bass carried by trains on newly laid tracks along the shoreline.

The rivers in the Bay region were stocked just before the Civil War. Since then, anglers have targeted smallmouths for their acrobatic leaps when hooked. They also make fine table fare, though most anglers today tend to practice catch-and-release.

Here is a summary of the state of smallmouth bass on the various rivers:

Upper Potomac River, MD

From Cumberland in Western Maryland to Great Falls near Washington, DC, the upper Potomac flows for 80 miles, straddling the boundaries of Pennsylvania and Virginia and West Virginia.

The number of juvenile smallmouths has been consistently low there the last 10 years, especially the last three springs with high flows.

“The problem is, we have good adults in the population but they are not being replaced in the numbers that we’d like to see,” said Michael Kashiwagi a regional fisheries manager with the Maryland Department of Natural Resources. “That’s a deciding factor.”

Kashiwagi agrees with studies that find a toxic soup of chemicals from medicines and agriculture are depressing immune systems in bass, making them more susceptible to other stressors, such as viruses, bacterial diseases and parasites. Warmer water, combined with low depths, can create conditions that increase these threats.

“In the last 30 years, the watershed has increased by more than 1 million people and that’s a huge factor also,” he said, referring to added pollution and habitat problems.

Nonnative flathead catfish are spreading throughout the river, likely eating both bass fingerlings and prey fish that bass depend on, he said.In the South Branch of the Potomac, up to 85% of bass disappear after reaching about 3 years of age. (Dave Harp)

Bass guides who use the river now split trips with other bass rivers such as the Susquehanna and Shenandoah depending on river conditions and catch rates.

To boost the river’s flagging bass numbers, the state last spring caught about 30 adult bass by lightly shocking fish from a section of the river and from willing anglers at a bass tournament for use in a hatchery.

Unfortunately, the bass did not like languid hatchery ponds and did not reproduce. The agency ended up buying 2,000 juvenile bass from a private hatchery in the Midwest to stock the upper Potomac. The experiment will be tried again in 2020 using different hatcheries.

South Fork Shenandoah River, VA

The South Fork of the Shenandoah has long been known to anglers for its high numbers of bass that could bend rods many times an outing. But that was before a fish kill in 2004 turned hundreds of bass belly up. There have been three other, less-destructive fish kills since then.

Highs and lows in the spawning classes have not helped. To protect the most productive spawners, anglers are not allowed to keep bass 11–14 inches long.

The emerging pattern of high water during spawns is a major concern for Brad Fink, a fisheries biologist with the Virginia Department of Game and Inland Fisheries. “We could have to try to spawn fish in a hatchery if it happens each year,” he said.

But he said he is hopeful that very favorable conditions for reproduction last spring should result in one of the best classes of juvenile bass in 22 years. And, he stressed the river still has fishable numbers. “I’d go float the river,” he said.

Most of all, Fink would like to see more focus on agricultural practices that reduce the runoff of harmful chemicals as well as a statewide emphasis on improving waterways in general.

“We know there’s stuff that’s affecting fish populations and just better water quality would fight that. And we need to clean it up for ourselves, too, not just the fish. I feel we’re not going backward anymore. [But] we need to work on getting it better, not just the status quo.”

Susquehanna River, PA

Once one of the meccas for smallmouth fishing on the East Coast, the Susquehanna River has been beset by the most publicized and alarming health problems for smallmouth bass, including die-offs, open sores and ugly black splotches. “Intersex” fish — male fish found with female egg cells growing in their testes — have appeared, too. Mysterious fish kills in the early 2000s set off a near-collapse of the famed smallmouth fishery. A moratorium on keeping bass has been in effect for nine years.

The problems with Susquehanna smallmouths have been intensely studied and debated. The former executive director of the Pennsylvania Fish and Boat Commission unsuccessfully battled to get the state’s Department of Environmental Protection to declare the river impaired, which would have required the state to address the problems.

In June, DEP declared the lower and middle portions of the river impaired for aquatic life, after finding low numbers of aquatic insects, along with high pH levels. The report did not list causes of the impairments, but noted that high pH levels are often tied to algae growth from concentrations of nutrients that have run off the land.

Now, after several years of encouraging bass numbers, fish surveys by the state and angler observations again reveal a sudden drop in the number of adult bass.

“Abundance is down,” conceded Geoff Smith, the Fish and Boat Commission’s Susquehanna River biologist.An angler casts for smallmouth bass at sunset on the Susquehanna River in Pennsylvania. (Dan Nephin)

Smith said the drop-off is worrisome and that fish managers are scratching their heads over the cause. He wonders if high flows at the end of the spring stressed fish. Sudden drops in water temperatures, resulting from heavy rain, can kill fish, and high water can stress adult males that don’t eat when guarding nests.

The decline contrasts with several years of encouraging juvenile reproduction. Spring surveys showed the highest presence of juvenile bass in 15 years.

“If the abundance is down [in adults], we’re in a different set of scenarios now,” Smith said. “Ten years ago, we weren’t getting new fish. Recruitment is not our problem anymore.”

South Branch of the Potomac River, WV

“On the South Branch, a lot of people are frustrated,” said Brandon Keplinger, a fisheries biologist with the West Virginia Division of Natural Resources. “We have a super concentration of 2– and 3-year-old fish. But when you have poor recruitment, fish 7–10 inches are not there and people freak out.”

The river has seen a number of fish kills since the late 1990s and up to 85% of bass disappear after reaching about 3 years of age.

Keplinger thinks the same factors believed to be affecting the health of bass in other rivers — nutrients and chemicals washing off the land — applies to the South Branch of the Potomac.

But he also is concerned that high river flows in the spawning period could become an annual problem. “We’ve had four straight years with high water over the spawn,” he said. And six of the highest flows on the river in the last 100 years have occurred in the last decade.

Keplinger would like to see studies to check, as he suspects, if blooms of blue-green algae might be killing or stressing bass. He said such algae produce some of the same neurotoxins and endocrine-disrupting compounds found in pharmaceuticals and pesticides.

He also worries about increased fishing pressure on already stressed bass from the emergence of fishing kayaks. The simple movement of kayaks through more shallow areas, unreachable by larger bass boats, scares fish from preferred habitat and possibly from spawning beds in the spring.

“When I float the South Branch, I displace fish. Kayaks can affect fishability,” he said.

But like his colleagues in other states, Keplinger is excited about last spring’s spawn — the best on the river in 15 years. “The good thing is, with a couple good young-of-the-year classes, the river can rebound really quickly,” he said.