Yellowfin Tuna — Research & Methodology (v1)
Last updated: 2026-03-30
This page documents the variables we use for Yellowfin (v1), 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 (overview)
Yellowfin is an offshore all-day rating (no Major/Minor windows) built from phase lift, illumination lift, and a capped ocean block (SST + chlorophyll + gradients). Research chooses the drivers; we calibrate thresholds and weights so the output is stable. Proprietary calibration details stay private.
Variables (what’s research-backed vs calibrated)
Research-backed means the driver/pattern/mechanism is supported by open-access sources. Calibrated means we chose the exact thresholds/weights/caps to make a stable 1–5 score and to avoid double-counting.
Moon phase
Research-backed: an open-access offshore tournament summary reports Yellowfin catch-rate peak at First Quarter.
Calibrated: the exact smooth curve shape is a product choice (continuity + stability).
Source (open PDF): NC Sea Grant — Hook, Line & Science (Winter 2020)
“Scientists found a relationship between catch rates and lunar phase for 5 of the 8 species as shown here…
Yellowfin tuna first quarter”
(PDF p.2)
Lunar illumination
Research-backed: Yellowfin night depth varies with illumination.
Calibrated: lift sizes are conservative; illumination is modeled separately from phase.
Source (open PDF): Wright et al. 2021 — Frontiers in Marine Science
“The average depth during the night varied with the lunar phase, with shallower dives (averaging around 20 m) when there was low illumination (new moon), and significantly deeper dives (averaging between 30 and 40 m) when illumination levels exceeded 0.85 (full moon; Supplementary Figure 3).”
(PDF p.5)
Environmental variables (verification)
This section focuses on the ocean data inputs (SST, chlorophyll‑a, and fronts/edges) and provides the primary open-access sources and quotes that support using them as drivers. Exact thresholds and lift magnitudes are proprietary.
Sea surface temperature (SST)
Research-backed: regional “optimal SST” bands exist in open-access habitat modeling.
Calibrated: we translate those bands into conservative scoring bands for a global 1–5 scale.
Source (open PDF): Siregar et al. 2025 — AACL Bioflux
“In June, the optimal SST for the presence of this fish was in the range of 31.0-31.2°C. In July, the range shifted to a lower temperature, namely 30.5-31.0°C… in August… 31.3-31.6°C.”
(PDF p.1540)
Chlorophyll-a (CHL)
Research-backed: open-access response curves support a productive chlorophyll band for Yellowfin presence.
Calibrated: we keep CHL lifts capped and conservative to avoid coastal “false highs.”
Source (open PDF): Siregar et al. 2025 — AACL Bioflux
“…the high probability of Yellowfin tuna presence occurs in the range of 0.1-0.3 mg m-³ (Figure 7).”
(PDF p.1540)
Fronts/edges (gradients)
Research-backed: Yellowfin habitat suitability is linked to mesoscale oceanographic features and boundary regions between eddies.
Calibrated: our gradient thresholds are heuristics (kept small) because papers don’t provide universal °C/10km thresholds.
Source (open access): Ramírez‑Mendoza et al. 2024 — Scientific Reports
“Our results suggest that the spatiotemporal distribution of yellowfin tuna is linked mainly to mesoscale oceanographic features… especially towards boundary regions between cyclonic and anticyclonic eddies…”
(PDF p.4)
Limits and caveats
This page explains what PrimeBite is using for Yellowfin. It does not promise a catch. A 5.0/5 means stronger predicted conditions relative to the model benchmark, not guaranteed fish.
- Yellowfin is an all-day offshore rating. PrimeBite does not claim Major/Minor moon-position windows for Yellowfin.
- The research is region- and gear-specific. PrimeBite uses those studies to choose drivers and direction, then calibrates the public-facing score privately.
- Weather is not a live Yellowfin rating driver right now. The model uses moon phase, lunar illumination, and oceanography.
- If ocean inputs are missing or still loading, the app may show unknown, no reading, or a partial explanation instead of pretending the ocean story is final.
- PrimeBite publishes the evidence and caveats, but keeps exact thresholds, weights, caps, and reproduction-ready equations private.
Source list
These are the open-access Yellowfin sources used on this public page. Each link points to the public source; page references match the quoted or cited part of the source.
- NC Sea Grant — Hook, Line & Science (Winter 2020) — moon-phase tournament summary, PDF p.2.
- Wright et al. 2021 — Frontiers in Marine Science — illumination / night-depth quote, PDF p.5.
- Siregar et al. 2025 — AACL Bioflux — SST and chlorophyll response-curve discussion, PDF p.1540.
- Asuhadi et al. 2025 — Ilmu Kelautan — supporting habitat-model context for SST and chlorophyll.
- Sambah et al. 2021 — AACL Bioflux — supporting Indian Ocean SST/chlorophyll context.
- Ramírez-Mendoza et al. 2024 — Scientific Reports — mesoscale feature / eddy-boundary quote, PDF p.4.
- Yang et al. 2024 — Fishes — chlorophyll-gradient / front-supporting feature-selection paper, PDF p.16.
- NOAA Fisheries — Pacific Yellowfin Tuna — open habitat overview used for general warm-water range context.
Changelog
- 2026-03-30: Expanded the public Yellowfin page to include limits/caveats, a fuller source list, and a current audit-date refresh without exposing private calibration details.
- 2026-02-15: Published the first Yellowfin public methodology page with public driver explanations and quote-backed evidence.