Blue Marlin — Research & Methodology (v1)
Last updated: 2026-05-25
This page explains the public Blue Marlin model story: what PrimeBite uses, what the research supports, and what the limits are. We do not publish the exact numeric tuning or any reproduction-ready recipe.
How it works (overview)
Blue Marlin is an all-day rating built from three drivers: moon phase, sea-surface temperature (SST), and Atlantic seasonality.
The architecture is direct rating-points attribution: the displayed rating equals 1.0 (baseline) plus the contribution from each driver. No hidden caps, no rounding rows, no multiplicative adjustments. The math you see in the app is the math that produces the number.
Blue Marlin v1 ships two calibrated cohorts: NW Atlantic (Bahamas through the Carolinas, Gulf of Mexico) and SW Atlantic (Brazil and equatorial waters). NE Atlantic (Madeira, the Canaries, and the Azores) coverage is coming in a future update.
Research chooses the drivers and the direction of the story. PrimeBite calibrates the exact curve shape, thresholds, and weights so the score stays stable on a 1.0–5.0 scale. Those exact numeric tuning values are proprietary.
Variables (what's research-backed vs calibrated)
Research-backed means the driver, pattern, or mechanism is supported by open-access or peer-reviewed sources. Calibrated means we chose the exact curve shape, thresholds, weights, or caps to produce a stable 1.0–5.0 score and to avoid overclaiming from region- or gear-specific studies.
Moon phase (full-moon peak — NW Atlantic only)
NW Atlantic — research-backed
Orbesen et al. 2017 (Bull. Mar. Sci. 93(2):573–589) studied US pelagic longline sets in the Gulf of Mexico from 1998–2014, covering 4,805 sets. They found higher Blue Marlin catch rates during daytime sets in the full-moon illumination period.
"Four taxa (lancetfish, blue marlin, white marlin, and rays) all had higher catch rates during the day and during the period of maximum lunar illumination."
SW Atlantic — no detectable moon effect
Two independent studies found no significant moon-phase effect on Blue Marlin catch rates in the SW Atlantic:
- Hazin et al. 2007 (ICCAT Coll. Vol. Sci. Pap., n=53,713 sets): moon phase was dropped from the final GLM at less than 1% deviance explained. This is the largest single Blue Marlin CPUE dataset in the literature.
- Afonso et al. 2021 (Fisheries Research, n=186 Blue Marlin): color × lunar interaction p=0.593 (not significant) for Blue Marlin specifically.
With two independent NULL sources, the SW Atlantic cohort uses no moon contribution by design.
Calibrated: the exact moon weight for the NW Atlantic is proprietary.
SST (sea-surface temperature)
Research-backed: Orbesen et al. 2017 published a 5-bin SST coefficient table showing catch rates roughly 18× higher in the warmest band (greater than 29°C) compared to the coldest (less than 21°C).
Cross-confirmed by multiple independent sources:
- Goodyear 2002 (ICCAT): basin-wide habitat suitability optimum at 26–27°C for Blue Marlin.
- Hazin et al. 2007: SST significant in the SW Atlantic GLM (p less than 0.0001).
- Martinez-Escauriaza et al. 2021 (Sustainability): NE Atlantic Madeira SST significant at p=0.0007.
Calibrated: the exact SST curve shape and thresholds are proprietary.
Seasonality (hemisphere-aware)
NW Atlantic
- Hammond 2001 (SCDNR Carolinas, n=1,610): May–July accounted for 87% of captures, with June–July as the apex.
- Martinez-Escauriaza et al. 2021 (Madeira): Month explained 78% of CPUE deviance. June–July peak.
SW Atlantic
- Amorim 2009 (ICCAT, SE Brazil): Q1 + Q4 austral summer peak from yacht-club tournament data.
- Mayer 2019 (USP thesis): Q1 + Q4 weak positive seasonal signal from Bayesian modeling of Japanese longline data 1970–2009.
Calibrated: the exact monthly proportions for each cohort are proprietary.
What's NOT included (and why)
- Chlorophyll / fronts / eddies: zero direct Atlantic Blue Marlin CPUE evidence links these to catch rates. Pacific chlorophyll results exist but are excluded under PrimeBite's Atlantic-stock-only policy for this species.
- Wind / pressure / rain / NAO: not significant in the Atlantic Blue Marlin literature. Wind was explicitly NULL in Ortiz 2001; pressure, rain, and NAO were not significant in Martinez 2021's adjusted GAM.
- Lunar illumination as a separate driver: Afonso et al. 2021 specifically tested lunar illumination × catch for Blue Marlin and found p=0.593 (not significant). This is evidence of absence, not just absence of evidence.
- Major/Minor solunar windows: Blue Marlin is rated as a day-level value. No published evidence supports sub-daily window effects for this species.
Limitations / caveats
- The moon-phase evidence comes from Gulf of Mexico pelagic longline data (Orbesen 2017). PrimeBite extrapolates this to the broader NW Atlantic with an in-app disclosure for users south of 18°N.
- SW Atlantic moon contribution is zero by design, anchored to two independent NULL sources (Hazin 2007 + Afonso 2021).
- NE Atlantic (Macaronesia) is gated in v1 because no published Blue Marlin moon-phase analysis exists for that region.
- SST evidence is primarily from the Gulf of Mexico (Orbesen 2017) and Madeira (Martinez 2021). PrimeBite applies a single SST curve basin-wide as a modeling choice.
- A single research group (Orbesen) provides both the moon and primary SST evidence for the NW Atlantic cohort.
Sources
- Orbesen et al. 2017 — Bull. Mar. Sci. 93(2):573–589
- Hazin et al. 2007 — Coll. Vol. Sci. Pap. ICCAT 60(5):1652–1662
- Afonso et al. 2021 — Fisheries Research 235:105822
- Goodyear 2002 — ICCAT Coll. Vol. Sci. Pap. 54(3):834–846
- Martinez-Escauriaza et al. 2021 — Sustainability 13:8975
- Hammond 2001 — SCDNR (South Carolina Department of Natural Resources)
- Jones, Judge & Ortiz 1998 — ICCAT Coll. Vol. Sci. Pap.
- Amorim 2009 — ICCAT Coll. Vol. Sci. Pap.
- Mayer 2019 — USP (Universidade de São Paulo) thesis
- Andrzejaczek et al. 2025 — Springer Nature (cross-billfish review)
Changelog
- 2026-05-25: Blue Marlin v1 launched with 2 active cohorts (NW + SW Atlantic). NE Atlantic (Macaronesia) gated pending local evidence.