Fisheries biologists conduct periodic reservoir sampling throughout Virginia using daytime boat electrofishing to target and assess Largemouth Bass populations. Surveys are generally conducted in a manner allowing comparisons to be made concerning these populations. Since many anglers seek bass, and fish considered over 20 inches are considered “memorable” based on national metrics; the accompanying table provides rankings for abundance of bass over 20”. Lakes are sampled on a rotating schedule depending on several factors including use, past indices and volatility. Some lakes are sampled annually, while others may have a rotation lasting several years. Often, there is little or no significant change between surveys, but spring weather fronts sometimes play havoc with catch rates—if fish are too deep, they are not vulnerable to the gear.
The term “CPUE-M” (or Catch per Effort of Memorable bass) incudes catch rates of bass over 20”—an indication of true trophy potential. These numbers should help anglers choose a resource that may provide the best chance to catch an exceptionally large fish rather than numbers of medium sized bass (see CPUE-P or catch of 15”+ bass per hour).
Several factors can bias data (e.g., weather conditions, fish behavior), but samples were conducted with efforts to minimize these. All of these lakes are considered reservoirs (e.g., those impoundments exceeding 500 acres vs. “small impoundments”), but there is great variability in size. Occoquan Reservoir produced an astonishing 11 memorable (and an extraordinary 94 preferred) bass per hour.
The following is a summary with lakes ranked by CPUE-M:
| Rank | Reservoir | Size | Year surveyed | CPUE-M | CPUE-P |
|---|---|---|---|---|---|
| 1 | Occoquan | 2,100 | 2020 | 11 | 94 |
| 2 | Sandy | 740 | 2022 | 9 | 50 |
| 3 | Chesdin | 3,100 | 2022 | 7 | 51 |
| 4 | Briery Creek | 845 | 2022 | 4 | 58 |
| 5 | Anna | 9,600 | 2022 | 4 | 40 |
| 6 | Smith Mountain Lake | 20,600 | 2022 | 2 | 35 |
| 7 | Flannagan | 1,143 | 2022 | 2 | 34 |
| 8 | Leesville | 3,270 | 2022 | 2 | 24 |
| 9 | Chickahominy | 1,230 | 2022 | 2 | 20 |
| 10 | Diascund | 1,110 | 2022 | 1 | 44 |
| 11 | Philpott | 2,880 | 2022 | 1 | 27 |
| 12 | Kerr | 48,900 | 2022 | 1 | 25 |
| 13 | Claytor | 4,633 | 2022 | 1 | 8 |
| 14 | Beaverdam Swamp | 635 | 2022 | 0 | 22 |
| 15 | Carvins Cove | 630 | 2022 | 0 | 16 |
| 16 | S. Holston | 7,580 | 2022 | 0 | 15 |
| 17 | Moomaw | 2,530 | 2022 | 0 | 7 |
| 18 | Little Creek | 947 | 2022 | 0 | 5 |