Mahi‑mahi — Research & Methodology (v1)
Last updated: 2026-02-15
This page documents the variables we use for Mahi‑mahi (v1), the open-access URLs behind each driver, verbatim quotes, and what is research-backed vs calibrated. We do not publish proprietary weights, caps, or equations.
How it works (overview)
Mahi is an offshore all-day rating built from phase lift, overlap and night-availability assumptions, and an ocean block (SST and optional chlorophyll). Research chooses the drivers; we calibrate weights and caps so the output maps to 1.0–5.0. Exact values are proprietary.
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 (L_phase)
Research-backed: an open-access offshore tournament summary reports Dolphinfish (Mahi‑mahi) catch-rate peak at First Quarter.
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…
Dolphinfish first quarter” (PDF p.2)
Calibrated: we use a smooth shared phase curve (First Quarter peak) and scale it into a lift; exact weight and scale are proprietary.
Average dawn/dusk opportunity (L_overlap_avg) — modeling assumption
Offshore day ratings don’t use time windows. For non‑Yellowfin offshore species we include a small fixed overlap lift so overlap isn’t implicitly treated as 0 in a 24‑hour score. This is a modeling/UX assumption (not claimed as a research effect size).
Night availability (L_time_avg)
Research-backed (context): Mahi spawning events are predicted to occur at night and chiefly at the new moon phase (context; not a universal CPUE effect-size study).
Source (open access): Schlenker et al. 2021 — Frontiers in Marine Science (PDF)
Calibrated: we translate diel context into a small fixed all-day average lift; exact value is proprietary.
Environmental variables (verification)
This section documents what the papers say (verbatim quotes with page pointers). How we map that into a stable rating uses proprietary thresholds and caps.
Oceanography (SST + chlorophyll‑a) (L_ocean)
Research-backed: multiple open-access studies show SST and chlorophyll-a covary with dolphinfish/mahi CPUE/habitat, but ranges are region-dependent.
SST anchors:
Marín‑Enríquez & Muhlia‑Melo 2018 (PDF)
“...dolphinfish preferred warm waters (24–28°C)...” (PDF p.1)
Martínez Arias et al. 2022 (PDF)
“Higher values of CPUE occurred in temperatures between 25.5 and 27.5 ºC. Above 27.5 °C and below 25.5 °C, CPUE decreases.” (PDF p.5)
“...are generally restricted by the 20°C isotherm (Gibbs and Collette 1959).” (PDF p.4)
Hammond 2008 (SEDAR document page)
“Dolphinfish were shown to utilize ocean waters with temperatures ranging from 16.0 to 30.5°C.” (Hammond 2008; quoted in our fact-check log)
“...tolerated temperatures from 15°C to 29°C but would stop feeding at 18°C (Hassler and Hogarth 1977).” (PDF p.76)
Chlorophyll anchors:
“...low concentrations of chlorophyll‑a (<0.02 mg/m3) ...” (Marín‑Enríquez & Muhlia‑Melo 2018, PDF p.1)
“82.90% of total fish... was caught in waters with concentrations of chl‑a between 0.05 and 0.25 mg/m3...” (Marín‑Enríquez & Muhlia‑Melo 2018, PDF p.5)
“Higher values of CPUE occurred in places where Chl‑a varied between 0.5 and 2.2 mg/m3. Below and above these values respectively, CPUE decreased.” (Martínez Arias et al. 2022, PDF p.5)
Calibrated: SST is required (if missing, ocean is neutral). We apply a cold-water gate so CHL does not cancel cold penalties below a set threshold, and an ocean cap; exact values are proprietary.