The People's Posidonia

Restoration at 516,000 to 942,000 euros a hectare is Bayraktarov et al. 2016, a global meta-analysis, at 2010 prices. A 2024 Balearic project came in nearer 2.5 million a hectare, so the recent Mediterranean figure is the expensive one. Protection and enforcement at 50 to 500 euros per hectare per year is the working figure from the Cilento programme.

Set against these, credits are projected at 34,033 euros a hectare in 2035 rising to 41,221 by 2050 (ARTEMIS 2025). Comparing a 2050 projection against a 2010 cost basis spans forty years of price basis in one sentence, so both vintages are printed wherever the comparison appears. The conclusion holds either way and holds harder against the recent figure: credit revenue does not fund active restoration. It can fund protection, which is what this proposal does.

Posidonia grows about a centimetre a year, so a meadow lost is lost on a timescale of centuries. This is an argument about sequencing and where the first euro goes, not an argument against restoration.

Newer mapping is being produced and released, so the point is not that one map is old. The point is the interval. A five-year cycle can describe a meadow. It cannot support a patrol, an anchoring decision, or an avoided-loss claim, all of which turn over inside a season.

The extent this proposal works against is 5,310 hectares across the Cilento coast, or 1,075 hectares within Pollica's own bounds. Both are computed by spherical polygon area over the ISPRA features held in the repository, on 4 August 2026, and both can be re-run. Which footprint the programme covers is an open scope decision and every ceiling figure moves with it.

One correction worth stating plainly. Until 4 August 2026 three internal working documents carried a different extent figure, inherited from the starting point of a chart rather than computed from the survey. It was caught, retracted, and replaced with the two areas above, both of which derive from the ISPRA features themselves and can be recomputed on demand.

Periplus plans the line: which section, what spacing, how long, and what the boat is asked to cover. Triton takes telemetry off the vessel and attaches provenance to every point: a vessel, a route, a timestamp and a named operator, which is the audit trail a verifier asks for. The ecosystem map holds the living extent and condition, integrating the ISPRA survey with open models. Meadow Futures compares what was found against what was expected and runs protection scenarios forward. The decision is what comes out: where to patrol, where to moor, where to dive next.

The return edge is the part that matters and the part the proof of concept buys. Today a survey line can be planned and a run can be captured; carrying returns all the way through to the map that sets tomorrow's route is the loop this first phase closes.

The same loop is substrate-neutral. The geometry, the trust weighting and the impact model carry no species term; only the habitat source and the growth model are specific to Posidonia.

The transaction is not a vessel hire. The boat is already going out, the day is already funded by visitors, and a student is already aboard. The survey rides along. That is why the marginal figure is about 50 euros a day rather than a charter rate, and it is why the network can plausibly sustain itself: nothing has to create the shift from extraction to stewardship, because the collapse of the fishery and the arrival of ecotourism have already begun it.

The capital item is the instrument, not the labour: side-scan sonar is about 8,000 euros per boat, alongside temperature and salinity sensors, GPS and a phone.

The third state is cultivation, and it has a Mediterranean precedent rather than a technical one. In the Kerkennah Islands families hold named plots of seabed they fish and tend with fixed passive traps. A coast can own and tend its sea floor. It can also lose it, which is what is happening there now.

A record owned by a project ends when the project does. A record held by the comune is one a community can act on and a verifier can audit, and it is what makes the monitoring independent of the parties being monitored. Island Lab supplies the method, the tooling and the quality control; the community owns the data. That split is deliberate.

The closest working example is Torre Guaceto, where two municipalities and a conservation organisation manage the reserve jointly through a consortium, and the fishermen sit on a standing co-management roundtable alongside scientists and authorities rather than being consulted by it.

Carbon at 24 euros per tonne of CO2e (band 11 to 27) gives 9.84 euros per hectare per year at 0.41 tonnes durable. Biodiversity adds 150 per hectare per year (band 50 to 500). Stacked, 159.84 per hectare per year, which across 1,075 hectares is a ceiling near 172,000 a year and across 5,310 hectares near 849,000. These are ceilings gated on verification being funded, not forecasts, and the honest band is roughly tenfold.

Two figures were corrected upward in confidence and downward in value while preparing this. Carbon was carried at 40 euros a tonne until it was sourced properly; the sourced central is 24. That correction is stated here because a number revised downward and shown with its band is worth more than one that survives until someone checks it.

Verification and monitoring, reporting and verification carries no figure here. No Posidonia credit has issued on any registry, so there is no verifier fee to derive one from, and inventing one would undo the point of the rest. The headroom instead: below about 147,000 a year at the Pollica footprint the central case still covers its operating cost.

The separate figure of 86,000 euros per hectare per year, sometimes quoted for Posidonia, is a 2024 French court ruling reported via WWF MMI 2025 in ARTEMIS 2025. It is a judicial valuation of harm rather than capturable revenue, and it is not a credit price.

The mapping and monitoring surfaces are built and running: the ecosystem map integrating ISPRA extent with open ocean models, the survey planner, the scenario tool, the investment board, and the trust layer that attaches provenance and uncertainty to every reading. All of them open at their own addresses.

What has not run is a survey on real returns, end to end, on this coast. Two outings have been made and the protocol has been demonstrated on generated data. Closing that gap is what the first phase is for, and it is stated here rather than left to be discovered.