Fish Salvage

Environmental Systems Analysis, Inc. (ESA) performed a fish salvage operation at a one-sixth of an acre, temporary, erosion and sediment (E&S) control basin, located at Clarksburg Village, in Montgomery County, MD.  The basin had a thick layer of unconsolidated silt, and the pool elevation was pumped down approximately three-feet to a mean one-foot of water to help concentrate any wildlife that might occur in the basin.  Thank you to Jim and Will of our ESA staff and also to YPG Construction Services for the coordinated pump-down and assistance with live capture.

Knowing that we were going to perform a fish salvage, we had to be permitted through the Maryland Department of Natural Resources, Fisheries Service (Inland Fisheries), as it is otherwise illegal to transport fish from one water body to another.  Per permit requirements, we are obligated to report our findings and cull any non-native invasive species.


ESA used a 10-foot jon-boat as a sled, with a rope from shore to guide the boat.


A 30-foot weighted seine and several various sized dip-nets were employed.


A series of seven seine passes covered the entire basin of the pool.


Approximately 3,000 fish were captured and relocated.


All of the fish appeared to be one to two-inch green sunfish, all in the same age and size class (fingerlings).  Four or five green sunfish were captured that averaged five or six-inches (palm-sized class), which were possibly the breeders.


Large coolers with cold water and aerators were used to hold the captured animals.  So as to not stress the fish by having them crowded and confined for any length of time, we made three trips to the relocation site, after every other haul.


The green sunfish (Lepomis cyanellus) is a native fish, naturally occurring in the central United States, west of the Appalachians and east of the Rockies.  This species has been introduced into Maryland and is considered naturalized, occurring in most of Maryland’s nontidal waterways, stream pools, ponds and reservoirs.

This species is characterized by the blue mottling streaks present on the sides of the head and cheeks.  They also have a black spot on the ear plate and the outer edges of the fins are usually tinged in orange and/or yellow.  They grow to be about 6 to 8-inches, can weigh up to one-pound at maturity, and live up to six years.  Females of the species can lay between 2,000 to 26,000 eggs, which then hatch in 3 to 5-days.


Green sunfish frequently become overcrowded in small water bodies.  They are a pollution tolerant species, easily acclimating to various aquatic conditions including turbidity, and can hybridize with other sunfish, especially bluegill.  Being prolific producers (a pioneer species), they tend to overpopulate, especially in the absence of predator fish, and are often the first fish to find their way to newly created ponds.


Being a relatively aggressive omnivore, green sunfish are easy to catch, and are a favorite pan-fish with anglers.  This species occurs in the Little Seneca Creek watershed and the Black Hill’s Little Seneca Reservoir, near where this site is located.


Adjacent to the temporary erosion and sediment control facilities is a naturalized farm pond, stormwater management facility with a permanent pool and headwaters of Little Seneca Creek, and forested stream buffer.


It is this area that may have acted as a recruitment source for the fish observed in the E&S basin.  Overflow from storm events, waterfowl and small mammals can inadvertently carry fisheries from one water body to another, and which is likely the case at this particular facility.


Neighbors that live abutting this facility took recent photos of fish mortality during the two days of the draw-down, prior to conversion into a stormwater management facility.  We did not observe any mortality while performing our fish salvage.  However, during the rapid draw-down period to concentrate wildlife, dissolved oxygen levels may have greatly fluctuated.


It is not uncommon in very small pool systems to have a high dissolved oxygen (DO) readings during the daytime, and have them pummel out at night.  These variables are stressful to fisheries, and weaker fish can die as a result.


The E&S pond was never designed to be a wildlife feature, capable of sustaining fisheries.  A fish pond must have a deep area, capable of creating water inversions, underwater structure, an adequate drainage area to support flushing and/or groundwater infusion, nutrient cycling for an established food web, and a healthy balance of predator/prey.


The draw-down and stewardship salvage operation successfully removed wildlife that volunteered at the temporary facility.  Elm Street Development will now be constructing a series of stacked/tiered stormwater best management practices consisting of groundwater recharge sand filters and polishing pond, which will include an area for a permanent pool.  This facility will be planted to exceed current SWM Design Manual Standards, in promotion of shoreline wildlife habitat and opportunities for herpetological breeding.


The green sunfish check out their new digs.  The gravel substrate of the perennial stream at our release site included a series of active beaver dams that are backing water.  Because the dams are located along a low section of roadway, the dams will likely need to be dismantled and the beavers trapped and relocated to prevent flooding/freezing of the roadway.


All of these fish were released downstream on Little Seneca Creek at Newcut Road.  Other than the green sunfish, we observed only one crayfish and one green frog, which were also released with the fish downstream.  No snakes or turtles were observed, and no non-native invasive species were observed, culled or released.

The work day is not finished until all of our field equipment is power-washed!

As part of our company resume, ESA has performed numerous fish salvage operations in support of land development operations, and we own a Smith-Root backpack electrofisher, several sizes of seine nets, an electric and motorized jon boat and all manner of equipment necessary for salvage services.

We are actively involved with the removal of in-line farm ponds, stream restoration, biological and chemical stream monitoring, fisheries management, watershed management studies/plans, SWM retrofit design, SWM water quality monitoring, wetland mitigation design, performance maintenance and trend analysis monitoring and extensive research and monitoring of fish ladders.  At present, our largest client for fisheries management is the Federal government, at numerous locations throughout the greater Washington metropolitan region.