The survey is deliberately light on gear. Beyond standard scuba kit it adds only a handful of defined items, because the method moves the demanding work — identifying species, counting them — off the dive and onto the surface. Underwater, the diver positions, holds a stable no-contact station, and presses once.
Each item below earns its place, and two of them do the measuring the whole method rests on: the marked line and marker that fix the day's calibration, and the full-surround camera that records the circle of reef being counted.
Records the entire circle of reef in one capture — one press, no gaps. It must resolve and identify your target organisms at the day's visibility radius, be rated to the course's depth range, and produce a consistent capture from dive to dive. Insta360 is one current example that meets these criteria, not an endorsement; any equivalent camera qualifies.
Set to the analyzed mix. The course runs repetitive dives across a day; nitrox and a computer set correctly are what keep the no-decompression margin comfortable behind the gas plan.
The marked 30 m / 100 ft navigation line — the same one from Advanced Open Water — gives the calibration count K over its known length. A standard high-visibility marker of recorded size and colour gives the detection radius r, by the distance at which it fades. Two kick counts, one swim.
The ring is run by compass and kick count, from a fixed hub and a fixed north — no reel, no line laid on the reef. The whole navigation reduces to one rule: add 60° at each stop.
The field record: station identifier, hub reference, depth, the radius r and count K, date and time, and — after the dive — taxa and counts. It also carries a small heading rosette so the leg sequence reads at a glance underwater.
A phone or tablet with the iNaturalist app, used topside after the dive for species identification and logging. It never goes underwater and plays no role during the dive — identification is unhurried, from the capture, and can be checked a second time.
Mask, fins, BCD, regulator with SPG, and appropriate exposure protection — the recreational configuration your prerequisites are built on. Buoyancy holds your station over the reef with no contact; the rest of the rig only adds to it.
An ordinary camera sees a cone — a wedge of the surrounding reef out to the visibility radius. Building a full circle from it means several careful shots with unphotographed gaps between them, taken while holding position without finning off the mark. A full-surround camera removes all of that: one capture records the entire horizontal field, so the sample is the whole disk the radius defines. That clean disk is also why the survey's arithmetic stays simple — every count is divided by one area, π r², not a sum of wedges.
Both reach the same visibility radius r; only the full-surround capture takes in the whole circle in a single press. The disk it samples has area π r² — the denominator every count is standardized against.
The camera works alone; counting waits for the surface. There is no live image to monitor and no topside operator feeding instructions. Underwater, the diver's whole attention goes to position, buoyancy, the buddy, and the gas. The demanding work of telling species apart and counting them moves to the surface, where it can be done carefully and checked again.
Shoot from a held altitude. Height above the reef changes how readily small or cryptic life is detected at the edge of the disk. Measure r at the altitude you intend to shoot from, then hold that same altitude across all six stations and every re-occupation of the hub — and record it on the slate. Altitude is a controlled, recorded variable, not a free one.
Three checks stand between a capture and a usable count. The durable rule behind all of them: every counted frame is one a second observer could recount.
Specific settings depend on the camera you carry and change as gear does, so the durable guidance is about what to hold constant, not exact numbers:
Once your confirmed counts are in hand, the census tools turn them into a standardized index — no login, offline once loaded.