The upper Potomac River supports Maryland’s most popular smallmouth bass fishery. The Maryland Department of Natural Resources Freshwater Fisheries Program monitors the status of the fishery through annual juvenile and adult monitoring surveys. Recent recruitment surveys have shown juvenile smallmouth bass numbers to be below long-term average values. High river flows in late spring (May-June)have been shown to be a major factor
contributing to this reduction in juvenile numbers. High river flows
during and immediately after smallmouth bass spawn can scour nests, displace
fry, and limit juvenile growth and survival. Elevated spring flows experienced in 2016-2018 have resulted in consecutive years of poor recruitment and low year-class strength. While the number of larger adult smallmouth bass has remained steady, there are concerns about declining catch rates after multiple poor year-classes of young fish.
In a management action to try and improve juvenile recruitment, the Freshwater Fisheries Program is planning a pilot smallmouth bass supplemental stocking program on the upper Potomac River beginning in the spring of 2019. Supplemental stocking of hatchery reared juvenile fish can be effective in helping boost year-class strength and contribute to the overall fishery. A stocking plan has been developed to collect a small number of adult smallmouth bass this spring and move them to a state hatchery for spawning. The resulting fingerlings and adult brood fish will be stocked back into the river in sections that have experienced recent low levels of recruitment and juvenile survival. Monitoring will be conducted to determine growth, survival, and distribution of stocked juvenile smallmouth bass as well as their contribution to the fishery.
All parts of the pilot project will be documented and posted online for the public and anglers to follow. More details on the smallmouth bass supplemental stocking program are available in a project plan outline and slide presentation.
If you have additional questions or would like to provide feedback to the upper Potomac River smallmouth bass supplemental stocking plan, please complete the Potomac River Smallmouth Bass Survey.
Juvenile smallmouth bass seining surveys have been completed on the upper Potomac, Monocacy, and Conococheague river systems. Monitoring surveys are conducted every summer to check for natural reproduction and judge the relative strength of each years’ juvenile numbers. A 30ft shoreline seine is used for sampling at fixed stations along the length of these rivers. For the upper Potomac River juvenile numbers looked good with an average seine index score of 1.1 fish/seine haul. This is slightly higher than the long-term median score of 1.0 fish/seine haul. Juvenile recruitment also looked good for the Monocacy River with a seine index score of 1.6 fish/seine haul compared to the long-term median of 1.5 fish/seine haul. Conococheague Creek had a juvenile seine index score of 2.0 fish/seine haul, slightly below the long-term median of 2.2 fish/seine haul. This year’s successful spawning combined with the supplemental stocking of hatchery raised smallmouth bass in mainstem sections of the upper Potomac River should help raise adult numbers over the next few years.
Fishing and Boating Services Hatcheries Division and Freshwater Fisheries Program stocked 30,000 fingerling smallmouth bass in the Potomac River from Taylors Landing downstream to Edwards Ferry. Freshwater staff collected adult smallmouth bass from the Potomac in April to serve as hatchery brood. Over the last four months, staff at the Joseph Manning Hatchery spawned the bass in ponds with artificial nesting structures and reared the fry in fertilized ponds. Once growth had been maximized in the ponds, the bass were transferred to indoor circular tanks where they were trained to feed on an artificial diet to accelerate growth to a stockable size of 2 - 3 inches. The final step was transporting these fish to the Potomac River.
An additional 5,000 fingerling smallmouth were generously provided by the West Virginia Division of Natural Resources, Warmwater Hatchery Program for the Potomac, which forms Maryland's southern border and is popular with anglers from both states. Several consecutive years of high river flows during the spring have reduced spawning success causing lower catch rates for anglers. The hatchery fish will supplement natural reproduction, accelerating the recovery of the fishery and improving fishing.
upper Potomac River. The plot
illustrates the difference in population distribution of the 2019 sample
compared to 2015-2018 results.
Image 1. 22.5
inch smallmouth bass collected in 2019 fall electrofishing survey from
Shepherdstown section of the upper Potomac River.
The 2019 upper Potomac River smallmouth bass juvenile seining survey was completed with 11 locations sampled from Seneca upstream to Oldtown. Juvenile smallmouth bass were collected using a 30 ft shoreline seine, with the fish ranging in size from 2.5–4.0 inches. The average number of juvenile smallmouth bass collected per seine haul was used as a metric to compare sample sites and examine trends over time. The overall average seining score for the river was 0.7 juvenile smallmouth bass per seine haul. This is below the long-term median score of 1.0 fish/seine haul. Smallmouth bass juvenile recruitment varied greatly between locations. Some upstream areas had good numbers of juvenile bass. Sites in Paw Paw and Little Orleans produced seine scores above 1.0 fish/seine haul. Moving downstream, smallmouth bass juvenile numbers decreased. Unfortunately, at some of the downstream locations (Brunswick, Seneca), no smallmouth bass juveniles were collected or observed from shore.
When examining the trend in smallmouth bass seine scores over the past 20 years, the upper Potomac River has not had a strong hatch of juvenile fish since 2007. Above-average spring flows have had a negative impact on juvenile numbers. High flows during or immediately after spawning disrupt nests, displace smallmouth bass fry, and lead to high mortality of young fish. High spring flows in 2016-2018 have resulted in poor year-classes with fewer smallmouth bass entering the population. Additionally, extremely high 2018 flows scoured the river bottom causing aquatic vegetation to be almost completely absent in much of the river for 2019. This vegetation will return, but it will take some time. For 2019, smallmouth bass were able to successfully spawn in some sections of the river, but overall recruitment was below average.
580 Taylor Ave., Annapolis MD 21401
Call toll-free in *Maryland* at 1-877-620-8DNR (8367)
Out of State: 410-260-8DNR (8367)