MONETA, Va. – The Smith Mountain Lake Association Dock Watch program has completed its second year of monitoring.
The program began in response to harmful algal blooms found in 2023. Now, volunteers work to assess cyanobacteria conditions at docks.
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“Thanks to the dedication of our volunteers, we are building a baseline understanding of cyanobacteria distribution and abundance in Smith Mountain Lake. The goal of the program is to increase our understanding of the factors contributing to HABs and, ideally, be able to take action to reduce the probability of future harmful algal blooms.”
Mary Colligan, SMLA Dock Watch program co-chair.
The following was found from 261 samples collected in 2025, according to the Smith Mountain Lake Association:
- Target cyanobacteria were detected in 42.9% of samples in 2025, compared to 30.9% in 2024. Raphidiopsis remained the most commonly detected cyanobacteria and the only one observed at elevated levels. Three samples met the criteria for additional investigation and no HABs were formally designated by state agencies in 2025.
- Phycocyanin levels were generally low across docks and across the sampling season with 84% of the samples having a phycocyanin measurement of less than or equal to 10. Phycocyanin is a screening indicator for the presence of cyanobacteria. The Dock Watch program has set a phycocyanin level of 25 as being worthy of additional investigation.
- Higher phycocyanin levels were more likely to occur with lower water clarity and warmer water temperatures. Water clarity was the strongest single predictor, accounting for approximately 21% of the variation in phycocyanin levels. That highlights the complex nature of cyanobacteria dynamics at docks at Smith Mountain Lake overall.
You can find the full program report here.