I had the privilege recently to sit down with John Mullican, the Field Operations Manager of Freshwater Fisheries for Maryland DNR, to discuss the status of the upper Potomac. John has worked for Maryland Freshwater Fisheries for over 38 years and is a wealth of knowledge on the Maryland waterways, the fish, and of course the upper Potomac. I hoped to only take a short amount of John’s time but our mutual love of the river and fishing took over so it became a lengthy conversation, and I could have kept on going! Here is a little summary of the things we talked about, I will include links to the Maryland DNR’s web page if you are curious to read more about anything we discussed. They have a newly revamped site and eager to share the results of all of their studies.
2018 Flooding and the Impact
High water years affect species differently. For some of our cold-water trout streams, the additional water can be beneficial. It keeps the flows up and temperatures down and because of the way they spawn, they can cover their eggs with gravel to protect them from the high flows. Generally, the trout streams had better hatches than we would have otherwise expected.
As far as the bass population goes, they are nest builders. They seek calm, protected areas to build their nests. Generally, you will get the best reproduction when you have average river flows that are stable. When you have average flows that are stable, you have the most spawning habitat available to the fish. This allows them to get through the nesting process without any disruptions. Bass are batch spawners, so if they begin to spawn and the high water interrupts them, they can try again. So just because you have a high-water event in the spring, it doesn’t necessarily mean you will lose that year class. Adversely, if the bass are spawning behind grass beds, gravel bars, island points, eddys or other protected areas that could lose water during dry conditions, they must move and spawn in main river areas behind ledges and boulders that are can become less protected when the river levels rise. The best spawning areas have a large, permanent rock structure that even under high flows are still a protected area.
Don’t worry, though they’re still in there! Adult bass are extremely adaptable to volatile river conditions.
Walleye Stocking Program
Did you know the upper Potomac provides a high quality Walleye fishery?
We do get natural reproduction of Walleye, but we also supplement that every spring with additional stocking. In recent years we have seen an increase in the number of Walleye. They were first introduced to the river in 1979 and since then, their numbers have gone up. In 2001 Walleye had a great natural year class and we stopped stocking for 10 years or so. In the 2012-2013 time frame we reinitiated the stocking program to supplement some moderate year classes. Brood fish are collected from the Potomac in March and taken to a hatchery for spawning. The fingerlings and brood are then stocked back into the river from Little Orleans, MD to Harpers Ferry, WV. Those fish are marked with Oxytetracycline (OTC). The fry are put into a bath that has the OTC. The OTC will bind to their otolith a bony structure in their inner ear and mark it. Follow up sampling shows that on average, hatchery fish make up about half of the annual year class. This shows that the stocking efforts were worthwhile and contributing to the fishery. The highest populations of Walleye can be found between Dam 3 and Dam 5, and the most recent electrofishing survey show a good population of 15″ – 23″ fish
For more information please visit; http://dnr.maryland.gov/fisheries/Documents/2018_Walleye_Summary.pdf
Photo courtesy of Maryland Department of Natural Resources
Musky Population on the upper Potomac
Often you hear people refer to their catch as a tiger musky. It would be very rare and unlikely for someone to catch a tiger musky in the river. Most often they are catching true muskies. Tiger muskie, a sterile hybrid of the muskellunge and northern pike have not been stocked in the Potomac since 2006. The muskies that are there are naturally reproduced. There have been theories of how they got there, but nothing is proven. They can now be found anywhere from Cumberland all the way to DC. Once you get below the Shenandoah River the temperatures become a little more limiting. They are most abundant in the middle section of the River from Little Orleans to Dargan. That’s an area that has a few more cold water and spring influences to keep temperatures down. Catching a large muskie is an exciting experience, but they aren’t for everybody. It varies, but it takes about 9-13 hours to catch one. They take quite a bit of dedication.
Over eight hundred muskies have been tagged since 1997, with over three hundred of those have also been recaptured. The tags are visible on the leading edge of the dorsal fin on the left side of the fish. Scrape the algae back and you will reveal a four-digit number. It’s important to not the tag number, date caught, location of the catch, length and whether the fish was kept or released, then report to DNR. They use this information to monitor fishing catch rates and population size distribution, both are important to determine the quality of the fishery. If you fish for muskie, please consider participating in the Potomac River Muskie Catch Survey
Muskie catch survey; https://docs.google.com/forms/d/e/1FAIpQLSfL0R1KwSAHbVuB7JKvOAb9OsVX3i6B_qQmTYUWrdWET0wY3g/viewform
Photo courtesy of John Mullican
Invasive Species
A more recent problem we’ve faced with the high floods is the potential expansion of Snakeheads. They are native to China, Russia and Korea and it is part of their life cycle during monsoon season to access flood plains and reproduce. When things dry up, they can bury themselves into the mud. If they stay wet and wait it out until the next monsoon season they can make it back to the river. The same is happening now in the Potomac. They are incredible at expanding their area and moving up river, taking advantage of higher river flows to do so. Northern Snakeheads now occupy C&O Canal all the way up to Violet’s Lock. That is obviously upstream from Great Falls, a huge natural barrier, but once they get into the C&O canal, they can get back to the main river. With all the high water we have seen down in that area, Snakeheads could potentially show up in all kinds of places in the Potomac watershed.
To combat the Snakeheads from making back to the main river, Snakehead derby events sponsored by DNR, National Park Service and the U.S. Fish and Wildlife service have been held at Pennyfield Lock. This was done to bring awareness to fisherman of what they look like, to keep them when they catch them and help control the population. Bow fisherman have also been extremely effective in targeting Snakeheads.
Another invasive species is the Flathead Catfish. Since this fish was first collected during electrofishing surveys in 2012 the number has steadily increased each year. Studies have been started to gain more information on the species movement, growth and angler harvest. The known distribution is from Dam 5 to Edwards Ferry.
Smallmouth Bass Population and Surveys
Through the electrofishing and seining surveys done by DNR, we have determined that recent yearclasses have generally been below long-term average values for juvenile smallmouth bass. A main contributing factor are the high river flows during spring spawning season. The high flows have an impact on the nests, the displace the fry and limit the growth and survival of the juvenile bass. The concern is there will be declining catch rates of adult bass in future years if multiple poor year-classes of the juvenile fish persist. The seine haul surveys have shown average, to below average numbers for several years. While yearclass strenght is highly variable and poor yearclasses have occurred throughtout the survey period (1975 – 2017. 2018 was the first time that water levels did not allow for seining surveys to take place.) past history has shown above average years to offset the poor years. It has been almost 10 years since we have had an above average year class.
Although year classes have been average or below, electroshocking has shown an above average population of larger fish. The adult bass are categorized as stock (7-11”), quality (11-14”), preferred (14-17”) and memorable (17-20”). The numbers sampled of stock size bass are near the lowest in 10 years, which represents some of the more recent low seine hauling counts, while the numbers for quality, preferred and memorable sized bass are near the highest in years. Meaning, great fishing for all of us in 2019!
For more information please visit; http://dnr.maryland.gov/fisheries/Documents/2017_SmallmouthBass_Summary.pdf
Photos courtesy of Maryland Department of Natural Resources
Smallmouth Bass Stocking Program
Since 1975 DNR has monitored the year class strength of Potomac River smallmouth bass. This is done through seining surveys and electrofishing studies. A new 5-year stocking plan will start this year to supplement natural reproduction and to improve year class strength. A consequence of not initiating the new program would result in lower catch rates by anglers and fewer large bass.
A small number of adult smallmouth will be collected in the spring and taken to a state hatchery to spawn. Freshwater Fisheries has collaborated with a Potomac River tournament directorand loval anglers to collect the needed brood fish during a spring tournament. The brood bass will be returned to the river after the spawn. Before restocking the fingerlings to the river, the fry will also be marked with OTC, to allow biologists to determine the degree that hatchery fish contribute to the population. If enough young bass are produced, the fingerling smallmouth will be stocked from Dam 5 to Point of Rocks, at a rate to simulate an “average” yearclass. Fisherman can help the department determine trends in smallmouth bass population and the success of the stocking program by particpating in the Potomac River Smallmouth Bass volunteer survey. Along with standard fish surveys, fishermen catch data is very helpful in tracking population trends and fishing quality.
Please take a few minutes to fill this out after your fishing trips; https://docs.google.com/forms/d/e/1FAIpQLScvmCk5MaUBgI8NhTgqnLT4Vd04WakaC-zkmu86VzS-06Kk-Q/viewform
Did you know that the average mortality rate per year for bass 7″ and greater is 39%? I was shocked to learn this! Although a large percentage of that number is due to natural causes, we can all do our part by catch and release fishing….and of course using good fish handling practices.
To aide the fisheries department in helping to provide a better fishery for all of us, please take a moment to fill out this survey; https://docs.google.com/forms/d/e/1FAIpQLSfveczcNritdHsizQRAvqty2hPzStVx-wtjQ3ns5s6m9-GUcw/viewform
For more information about the smallmouth stocking program, visit http://dnr.maryland.gov/fisheries/Pages/smallmouth_bass_stocking.aspx
Thanks again to John for taking the time to sit down and talk to me!
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