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PrimeBite Fishing Bigeye Tuna Research & Methodology

Bigeye Tuna — Research & Methodology (v1)

Last updated: 2026-03-30

This page documents the variables we use for Bigeye (v1), the open-access URLs behind each driver, verbatim quotes, and what is research-backed vs calibrated. We keep proprietary calibration details private.

On this page

How it works (overview)

Bigeye is an offshore all-day rating built from phase (full-moon peak), night-availability lift, and a small capped ocean block (SST + optional chlorophyll). Research chooses the drivers; we calibrate weights and caps. Bigeye v1 is intentionally conservative. Exact values are proprietary.

PrimeBite does not use offshore Major/Minor moon-position windows for Bigeye, and it does not add day-to-day weather adjustments in v1.

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 curve shape/thresholds/weights/caps to produce a stable 1.0–5.0 score and to avoid overclaiming from region- or gear-specific studies.

Moon phase

Research-backed: Jatmiko et al. (2016) report significant differences among moon phases with the highest average catch rate at full moon in their dataset.

Source: Jatmiko et al. 2016 — ILMU KELAUTAN (open access)

“The result showed that the average catch rate of bigeye tuna differed significantly among the moon phases. Tukey post-hoc tests showed that the average catch rate at full moon was the highest among the groups with around 0.3/100 hooks.” (PDF p.1 / journal p.101)

Calibrated: the exact curve shape and scale are product choices (smoothness + stability); values are proprietary.

Night availability

Research-backed: tagging studies show strong diel vertical behavior (shallower at night).

Source (open PDF): Musyl et al. 2003 — Bigeye vertical movements

“At night, however, bigeye tuna generally restrict their vertical movements to the surface layer.” (PDF p.2)

Calibrated: we translate this into a small, fixed all-day-average lift; exact value is proprietary.

Oceanography (SST + chlorophyll-a/SSC)

Research-backed: regional studies support SST and chlorophyll (or SSC proxies) as predictors/covariates for Bigeye catchability/habitat.

Source (open PDF): Syamsuddin et al. 2013 — Fishery Bulletin (open access)

“SST was a more important oceanographic predictor of Bigeye Tuna catches than were the other environmental variables (SSHA and chlorophyll-a) in this region.” (PDF p.10)

Calibrated: we keep the ocean effect small and capped, require SST before the ocean block can score, and keep chlorophyll neutral when SST is missing, chlorophyll is missing, or SST is below 20°C. Exact cap and thresholds are proprietary.

Environmental variables (verification)

This section highlights the key open-access quotes behind the SST/CHL bands used in Bigeye v1.

SST anchors

Syamsuddin et al. 2013 (open PDF): PDF

“Our results indicate that Bigeye Tuna catches increased in areas with relatively low temperatures (24–27.5°C) and decreased at temperatures >27.5°C (Fig. 6B).” (PDF p.10)

Setiawati & Miura 2014 (PORSEC proceedings): quote verified from the project-cached PDF because we could not find a stable public PDF URL during the 2026-03-30 citation review.

“Statistical analysis showed the optimum of SST for bigeye tuna is less than 29.1°C and more than 27.4°C.” (cached PDF p.1 / Abstract)

Chlorophyll / SSC anchors

“High probabilities of Bigeye Tuna presence were observed … for chlorophyll-a levels ranging from 0.04 to 0.16 mg m–3.” (Syamsuddin 2013, PDF p.8)
“In addition, the optimum value of SSC was 0.055 to 0.175 mg m-3.” (Setiawati & Miura 2014, cached PDF p.1 / Abstract)

Song et al. 2009 (open access PDF): PDF

“0.090–0.099μg·L−1” (PDF p.12, Table 5; units note: μg/L = mg/m³)

Limitations / caveats

  • Bigeye in PrimeBite is an all-day offshore rating, not an hourly bite chart.
  • The strongest moon-phase and oceanography evidence is region- or fishery-specific, but PrimeBite currently uses one global Bigeye profile.
  • The fixed night-availability term is a calibrated all-day baseline. It does not create visible time windows or Major/Minor bites.
  • The ocean block is intentionally small and capped. If SST is missing, it stays neutral. If water is colder than 20°C, chlorophyll does not add extra lift.
  • A higher rating means better predicted relative conditions than a lower one. It does not guarantee a catch.

Sources

Changelog

  • 2026-03-30: added the missing limitations/caveats, sources, and changelog sections required by the current audit standard.
  • 2026-03-30: refreshed the Bigeye public citation trail and replaced the weak ResearchGate landing-page citation with a clearer cached-PDF disclosure note.
  • 2026-03-30: updated the public methodology wording so it matches the live all-day Bigeye model, including the neutral/missing-data ocean rules.