Largemouth Bass — Research & Methodology
Last updated: 2026-04-13
This page documents the current live Largemouth Bass profile, the open-access URLs behind each driver, verbatim quotes, and what is research-backed vs calibrated. We keep proprietary calibration details private.
How It Works
The Largemouth Bass profile uses the current Bass v2 structure: a day baseline plus an hourly activity curve. Unlike Walleye and Muskie (which use solunar window positions), Bass ratings are driven by environmental conditions: dawn/dusk timing, wind speed, water temperature, seasonality, and a small moon phase effect.
Rating Structure
- Day baseline (1.0–5.0): Represents the broader day setup before the exact hour is applied. It comes from seasonality, water temperature, moon phase, and a small built-in starting day level.
- Hourly activity curve: Shows how the rating changes throughout the day after dawn/dusk timing and hourly wind move the score up or down. Peaks are typically near dawn and dusk, with softer midday hours.
- Main app card: Today and Forecast show the expected daily range from the hourly curve, not one all-day Bass number.
- Best-stretch summary: The strongest short opportunity is still derived from the best contiguous 2-hour average, which powers the best-stretch story and lower detail surfaces.
- Best Times: Identifies the strongest windows from the hourly curve, typically around Dawn and Dusk.
What Drives the Rating
- Dawn/dusk proximity — Primary driver. Bass are most active near sunrise and sunset.
- Wind speed — Quadratic dome: optimal around 12 km/h (~7.5 mph). Both calm and high wind reduce catch rates.
- Water temperature — Warmer is better within the observed range (5.71–28.72°C / 42–84°F). Clamped at both endpoints — no extrapolation beyond the tested range. Estimated from 7-day air temperature history.
- Seasonality — Summer peak (June–July), winter trough (December–February).
- Moon phase — Small, conservative effect. One direct-angling study found full moon higher (p<0.01); telemetry warns patterns are not consistent year-round.
What Is NOT Used
- Barometric pressure — Two independent direct-angling studies found no significant effect.
- Cloud cover / light intensity — No confirmed evidence source after the original citation was retracted.
- Solunar window positions (overhead/underfoot) — No bass-specific evidence found after comprehensive search.
Study Limitations
- Mixed methods: Some sources use electrofishing CPUE or telemetry, not recreational angling CPUE. Effect directions are supported, but exact magnitudes may differ for hook-and-line fishing.
- Moon phase: One direct-angling study supports a full-moon bump (p<0.01), but telemetry warns patterns are not consistent across the year. Included with very small weight and single-source risk flag.
- Water temperature: Estimated from air temperature history (7-day exponential decay model). Accuracy ~1–3°C. No free freshwater lake temperature API exists. Linear-positive model is based on one study in one Iowa lake; clamped outside the observed range (5.71–28.72°C).
- Regional variation: Optimal temperatures and seasonal patterns may differ by latitude and lake type.
Ratings are relative indicators, not guarantees. Do not assume they apply universally. We use the evidence-backed direction of effects and calibrate magnitude for a stable 1–5 scale.
Variables
Every variable is classified as research-backed, calibrated, or excluded.
| Variable | Status | Evidence | Notes |
|---|---|---|---|
| Dawn/dusk influence | Research-backed | 3 independent evidence lines | Primary driver. Telemetry, electrofishing, and direct hook-and-line angling (p<0.005) all confirm crepuscular peaks. |
| Wind speed | Research-backed (single source) | 1 direct-angling study | Quadratic dome. Optimal ~12 km/h. Single-source evidence from one Iowa lake. |
| Water temperature | Research-backed (single source) | 1 direct-angling study | Warmer is better within 5.71–28.72°C (42–84°F). Clamped outside observed range. Estimated from air temp. |
| Seasonality | Research-backed | Multiple sources | Summer 3–4× winter activity. Monthly multipliers are calibrated shape. |
| Moon phase | Calibrated (direction-backed, single source) | 1 direct-angling study | Full moon higher (p<0.01). Telemetry warns patterns are not consistent year-round. Small weight. |
| Barometric pressure | Excluded (null result) | 2 independent direct-angling studies | Neither study found a significant effect on catch rate. |
| Cloud cover / light | Excluded (no confirmed source) | — | Original citation retracted; no replacement source identified. |
| Solunar windows | Excluded (no evidence) | N/A | No bass-specific open-access evidence found after 5 search sweeps. |
Key Quotes (Verbatim)
Dawn/Dusk — BASS-S1 (Hlina et al. 2026)
"Largemouth bass acceleration peaked during dawn (0.521 ± 0.012 m s⁻²) and slowly decreased throughout the day with acceleration being the lowest at night (0.278 ± 0.002 m s⁻²)"
— p.7–8, Results
Dawn/Dusk — BASS-S5 (McInerny & Cross 2000)
"Sample period F = 32.50, P < 0.0001 (< 120 mm TL); F = 55.91, P < 0.0001 (200-299 mm TL); F = 20.13, P < 0.0001 (≥ 300 mm TL)"
— Table 1, p.5
Wind — BASS-S6 (Maahs et al. 2022)
"We observed a quadratic effect of wind speed on bass weigh-in probability, with weigh-in probability being highest at wind speeds around 12 km/h"
— p.1522, Results
Water Temperature — BASS-S6 (Maahs et al. 2022) — Linear-Positive
"bass weigh-in probability was positively related to water temperature (β = 0.0451; 95% CI = 0.0058, 0.0844)"
— p.1519, Results
C1 linear-positive model within observed range 5.71–28.72°C. Clamped at both endpoints (no extrapolation). The prior BASS-S4 dome (peak 20–24°C) was demoted to context per the 2026-04-12 rebuild — Louisiana coastal estuarine electrofishing methodology does not match direct freshwater angling.
Moon Phase — BASS-S9 (Mallison 1988) + BASS-S10 (Hanson et al. 2008, context)
"The lunar influences upon angling success were significant at the .01 level."
— BASS-S9, p.10, Results
BASS-S9 (direct hook-and-line angling, 59 bass, 35 days) found full moon higher than expected, transitions lower. SINGLE_SOURCE. Key limitation from S9 itself (pp.18-19): the author notes moon phase and water temperature changed too slowly within the short 35-day study to be adequately separated.
"patterns were not consistent across the year"
— BASS-S10, p.1, Abstract
BASS-S10 (telemetry context) warns that lunar patterns are not stable year-round. BASS-S2 was previously cited here but has been deprecated (duplicate of BASS-S10 — both cached PDFs contain the same Hanson 2008 lunar paper; BASS-S10 is the canonical tag).
Barometric Pressure — Excluded (BASS-S8, BASS-S9)
"barometric pressure … were not significantly correlated (p>0.05)"
— BASS-S8, p.4, Abstract
"Wind direction, wind magnitude, barometric pressure, and solunar periods revealed no significant relationship"
— BASS-S9, p.11, Results
Two independent direct-angling null sources. BASS-S3 (Winter 1976) was previously cited here but has been retracted — the thesis never tested pressure or cloud cover (2026-04-09 forensic audit Finding #16).
Full Source List
| ID | Authors / Year | Title | Link |
|---|---|---|---|
| BASS-S1 | Hlina et al. 2026 | Seasonal effects on the acceleration of largemouth bass (Animal Biotelemetry) | |
| BASS-S2 | DEPRECATED | Duplicate of BASS-S10 — both cached PDFs are the same Hanson 2008 lunar paper; BASS-S10 is the canonical tag | — |
| BASS-S3 | RETRACTED | Winter 1976 never tested pressure or cloud cover (2026-04-09 forensic audit) | |
| BASS-S4 | Louisiana CPRA 2016 | DEMOTED to context — dome superseded by BASS-S6 linear-positive (methodology mismatch) | |
| BASS-S5 | McInerny & Cross 2000 | Seasonal and diel variation in electrofishing CPUE (MN DNR Report 451) | |
| BASS-S6 | Maahs et al. 2022 | Effects of limits on largemouth bass tournament capture (N. Am. J. Fish. Mgmt) | Article |
| BASS-S7 | Sylvia et al. 2020 | Bass behaviors and environmental conditions (Iowa State) | |
| BASS-S8 | Burkett 1981 | Hook-and-line vulnerability vs physicochemical parameters (EIU thesis) | |
| BASS-S9 | Mallison 1988 | Moon phase p<0.01, dawn/dusk p<0.005, pressure null (OSU honors thesis) | |
| BASS-S10 | Hanson et al. 2008 | Lunar telemetry context — replaces BASS-S2 (Fisheries Mgmt & Ecology) |
Changelog
- 2026-04-13: April rebuild truth-sync: replaced BASS-S4 dome with BASS-S6 linear-positive temperature, replaced BASS-S2 moon with BASS-S9 direct-angling + BASS-S10 context, updated pressure section from BASS-S3/S8 to BASS-S8/S9 (S3 retracted), added S9 and S10 to source table, marked S2 deprecated / S3 retracted / S4 demoted. 10 sources total.
- 2026-03-30: Refreshed the public Bass page after the live recalibration closure and full re-audit. Updated the visible app-story wording so it matches the current range-first Bass UI.
- 2026-03-12: Updated wording to match the live Bass v2 app model: day baseline + intraday modifier, hourly curve, and best contiguous 2-hour headline summary.
- 2026-03-08: Initial release. 8 open-access sources. Environmental day rating with hourly activity curve. Calibrated using 6-step evidence-anchored process.