Methodology
How vShark estimates relative shark interaction risk — and what it does not claim.
What vShark measures
vShark combines ecological observations, species-specific presence/hazard estimates, human exposure and consequence assumptions into a relative interaction risk assessment for a coastal location and time. It is experimental decision-support infrastructure, not a prediction of a specific shark attack.
Core formula
R(x,t) = E(x,t) × Σs [ Ws × Ps(x,t) × Cs ]
- E — human exposure
- Ps — species presence/hazard (logistic + thermal + detection decay)
- Ws, Cs — configurable species weight and consequence scalar
The public 0–100 index is a development mapping of raw R (currently × 120, clamped 0–100). It is not calibrated to incidents, expert rankings, or official NSW scales. Do not treat the number as a scientific or operational rating.
Risk bands (provisional)
| 0–24 | LOW |
| 25–49 | MODERATE |
| 50–74 | ELEVATED |
| 75–100 | HIGH |
Thresholds are versioned development defaults. We never use “SAFE”.
Confidence
Public UI shows one combined confidence (HIGH / MODERATE / LOW). It reflects data freshness, completeness, mock/stale feeds and coverage — not false precision. Missing inputs reduce confidence; they do not silently imply low risk.
Development parameters
Thermal optima, species weights and consequence scalars are development seeds stored in the database and model version record. They are not published biological constants. See RISK_MODEL.md.
What we never say
- SAFE TO SWIM
- NO SHARKS PRESENT / SHARK-FREE
- Guaranteed protection
- Prediction of a specific attack
Known limits (First Build)
- Model version 0.1.0-dev — development seeds, not validated biology.
- Open-Meteo is live as one Northern Beaches centroid, not beach-specific SST.
- NSW Beachwatch water quality is live as labelled context only. It does not enter the shark-risk score and is not a vShark swim clearance.
- iNaturalist, GDELT media volume, and whale/salmon climatologies are labelled context. They do not enter the shark-risk score.
- NSW SharkSmart, BOM and IMOS are not connected. MOCK detections do not enter the score.
- Without a live detection feed, public confidence cannot be HIGH.
- Species weights and the ×120 public scale are uncalibrated.
Always follow
Beach closures, lifeguard instructions, NSW Government shark-safety information, organisational safety procedures and professional judgement take precedence over any vShark output. vShark is not NSW DPI / SharkSmart, Surf Life Saving Australia, Northern Beaches Council, or the Bureau of Meteorology.