February 2024

    22 Feb February 2024

    Posted at 10:13h in LakeMatters by
    Building Fish Habitat at SML
    Although the primary purpose of Smith Mountain Lake is power generation, SML is an outstanding fishery which supports black bass (largemouth and smallmouth), hybrid striped bass (Stripers), sunfish, crappie, white and yellow perch, channel catfish, flathead catfish, white catfish, carp, and Asian grass carp.  

    The Virginia Department of Wildlife Resources (VA DWR) fishery biologists, stationed in Forest, Virginia, monitor and manage the SML fishery. Smith Mountain Lake Association (SMLA) Habitat, Submerged Aquatic Vegetation (SAV), and Invasive Species volunteers assist VA DWR in monitoring these three fishery health interrelated areas.

    Native SAV has been present in SML since formation in 1966. Hydrilla and other invasive weeds began growing out of control and degraded the recreational experience on the lake for many users, especially in small coves. Sterile Asian grass carp were introduced approximately ten years ago to feed upon and remove the Hydrilla, but unintentionally, they also depleted SML of most SAV.  This lack of SAV created a problem for the bass fishery because SAV provides protection for fry (juvenile fish) enabling them to reach a size and maturity enough to sustain their population levels.

    VA DWR fishery biologist, Dan Wilson, with the help of APCO funding, searched for a way to provide juvenile fish habitat and started with underwater rock piles, wood pallets, and some wood pyramid structures. These all helped.

    Since 2017, VA DWR has been modifying and deploying PVC fish habitat structures that have significantly increased the survival rates of the fry. These habitats have been deployed in approximately eight to ten feet of water at 217 locations throughout the lake as of 2023. Deployment locations are tracked by GPS latitude/longitude and are available to the public from VA DWR and SMLA.
     
    Completed fish habitat locations as of 2022 created by Franklin County GIS personnel in conjunction with SMLA and DWR location spreadsheets.
    Each fall, the VA DWR coordinates the assembly and deployment of approximately 35 new structures to locations throughout SML with the support of many APCO and SMLA habitat volunteers. APCO’s work barge serves as a platform to construct the units and transfer them to the DWR boats for deployment at preselected locations.

    Volunteers from DWR, APCO, and SMLA assemble on the barge where they don their life vests and receive a mandatory safety briefing regarding working on the APCO barge. APCO’s barge allows storage of all unit components and a large level surface to safely construct the units. The habitats consist of two main components which are tubes and slats. 
    The slats are inserted into the tubes in precise positions to provide the frame of the habitat structure. The base frame of eight tubes is shown in the following picture.  Cross bracing provides support to the habitat enabling the structure to maintain its form and spacing after deployment.
    Once the base frame has been completed, additional slats are placed in each of the remaining tube openings to create a dense web of pockets that small fish can hide and evade larger fish.  A completed unit consists of approximately 120 slats, 8 tubes, and 7 concrete blocks.
    After all slats have been installed, the unit is moved to the end of the barge where concrete blocks are secured to the structure with stainless steel zip ties.  Fully assembled units are then loaded onto the DWR workboat platforms, taken from the barge to the predetermined locations, and deployed in water approximately 8-10 feet in depth.

    The concrete blocks anchor the structures to the lake bottom. The location latitude and longitude are captured and logged into a spreadsheet. SMLA coordinates with Franklin County GIS personnel to record the locations on a map for use by the public.