2025 Invasive Vegetation Sampling Survey Findings

One of SMLA’s Invasive Species Committee’s main focus is monitoring the growth of invasive vegetation in SML. In addition to collecting weed reports from lakefront homeowners reports, we collaborate with the Scruggs Fire and Rescue Dive Team to conduct annual vegetation sampling dives.

These dives allow us to both identify vegetation species with a focus on invasive non-native species such as hydrilla and to compare weed bed growth from year to year. Hydrilla is particularly concerning because of its ability to grow rapidly and completely block navigation. The goal of this monitoring effort is to provide data for the Tri-County Lakes Administrative Commission to determine if weed remediation is required.

This year’s sampling survey has identified hydrilla at 10 of the 16 sites sampled.  The most affected areas are in the lower end of the lake.  Specifically, the Penhook and Bull Run/Little Bull Run areas have significant growth, but some hydrilla was also observed at Goodhue Marina up the Blackwater River and around Lucky Island at the confluence of Gills Creek and the Blackwater River.

In addition to finding hydrilla at more sites than last year, the area of existing beds have grown substantially relative to the 2024 observations of the same sites. These observations are consistent with the loss of effectiveness of the sterile grass carp that were stocked in 2013 to control hydrilla growth. The lifespan of this species of carp is 10-12 years.  Our findings are being used by TLAC to prepare their remediation plan, which will include restocking of sterile grass carp.