# B-vs-B' grade-set: S1_fishery — Coastal fishery on a collapse trajectory

SCENARIO (given verbatim):
A coastal fishery harvesting a single demersal stock has shown three years of declining catch-per-unit-effort and shrinking average fish size. The biologist's stock assessment estimates that current harvest exceeds maximum sustainable yield (MSY) by ~20% and that, on the current trajectory, the stock will cross a recruitment-collapse threshold within 4-7 years. The fishery is open-access in practice (no enforced individual quotas); ~120 small-boat operators across 5 villages depend on it for income, with fish-processing buyers downstream. A regulator has authority to set total allowable catch but has historically deferred to the industry.

Decision required: What intervention design preserves the stock without destroying the livelihoods that depend on it?

Success criteria: Stock biomass returns to MSY-supporting range within 10 years AND <20% drop in aggregate fisher income (averaged across the cohort, not per-boat). Failure = stock collapse OR a regulatory regime that pushes the bottom quartile of operators below subsistence.

4 candidate recommendations, labeled R1, R2, R3, R4.

## Recommendation R1
**Design: a co-managed, science-triggered catch-share system with a protected floor and a funded transition.**

**1. Set the target and the cut by the stock, not by negotiation.** Commission an independent stock assessment — funded from a levy, not from the industry, and published openly — to fix this year's total allowable catch. Because the stock is near a threshold it cannot easily climb back from, do not merely trim harvest to the sustainable level; cut modestly *below* it to build a rebuilding margin. The right cut is the smallest reduction that reliably puts biomass on a 10-year recovery path: model the trajectory and choose the gentlest credible one, because cutting harder than necessary is precisely what would push the weakest operators under. Practically this means roughly a 25–30% first-year landings reduction, front-loaded modestly and then eased as the stock responds.

**2. Convert open access into bounded, legitimate entitlements.** Issue a license to each current operator and divide the allowable catch into shares. Critically, give every operator an equal, non-transferable *basic* allocation sufficient for subsistence-level income, and distribute only the remainder in proportion to recent track record. This stops the race-to-fish (each boat now has a secure claim rather than an incentive to grab first) while structurally protecting the bottom quartile: their floor cannot be bought out from under them. Allow limited trading or pooling of the *above-floor* portion so efficient operators aren't trapped, but cap how much any one holder can accumulate and forbid sale of the basic floor, so the fishery cannot consolidate into a few hands and strand the small boats.

**3. Make condition and behavior visible, and attach proportionate consequences.** Track landings, catch-per-unit-effort, and average fish size on a shared, public dashboard. Enforce with a graduated ladder — warning, then fee, then temporary share suspension — rather than heavy punishment up front; proportionate enforcement keeps a small community willing to comply.

**4. Replenish actively.** Pair the catch limit with a seasonal closure during spawning and a small permanent no-take refugium. Fund a buffer reserve (from the levy and from above-floor share fees) that the rebuilding stock and the income-support measures below can draw on.

**5. Protect livelihoods through the transition, since a sound cut still bites in years 1–3.** Use the reduced fishing days to fund a temporary transition payment and paid stewardship work — monitoring, habitat repair, enforcement support — targeted at the lowest-income operators so aggregate cohort income stays within the 20% band and no one falls below subsistence. Tie landings to the local processors with first-purchase arrangements so the downstream village economy isn't gutted by the volume drop. Compensation must be funded and actually reach people, not promised in the abstract.

**6. Fix the governance, or the cut will be eroded.** The regulator's habit of deference is the central failure risk. Move the decision into a co-management council where operators, villages, processors, and independent scientists share votes, with a rule that industry interests cannot form a majority and that the published assessment sets the binding TAC ceiling. Pre-commit, in writing, to a harvest-control rule: stock-condition triggers automatically set next year's catch within a fixed band. This removes the annual lobbying fight and makes the science, not the loudest incumbents, the author of the limit. Keep assessment expertise independent of the fleet, and publish the funding, the data, and the rationale so quiet drift back toward over-harvest becomes visible.

**7. Adapt, and don't lift restrictions too early.** Recovery is asymmetric: a stock pushed near collapse rebuilds slowly and unevenly. Do not relax the catch share the moment CPUE ticks up. Require sustained evidence — recovering biomass *and* returning fish size held over consecutive assessment cycles — before easing limits, and ease them in stages.

**Final operating rule:** *Each year, an independent, publicly funded assessment sets a total catch on a rebuilding trajectory; that catch is split into secure shares with a protected, non-transferable subsistence floor for every operator and capped, tradable shares above it; condition is monitored openly, enforced proportionately, and replenished by closures and a refugium; the transition is cushioned by stewardship pay and processor linkages so cohort income stays within 20% and no one falls below subsistence; the limit is set by a pre-committed, capture-resistant harvest-control rule and eased only on sustained, multi-cycle evidence of recovery.*

## Recommendation R2
Treat the stock as a shared asset that collapses when everyone's individually reasonable catch sums past what the population can replace, and design an arrangement the fishing communities help build and police themselves — because a cap imposed from above by a body that has always deferred to the fleet will be enforced loosely and gamed, while a cap the villages co-author and benefit from is one they will defend.

Start by fixing the total catch to the biology, not to last year's landings. Set a total allowable catch each season pegged to the current stock assessment, beginning roughly 25–30% below present harvest so that take falls below the replacement rate immediately, and hold it there until biomass indicators recover. This is deeper than the 20% overshoot on purpose: recovery needs the stock to grow, not merely stop shrinking, and the extra margin buys distance from the collapse threshold while the window is still open. As biomass, catch-per-unit-effort, and average fish size climb back, raise the cap on a published schedule so fishers see restraint converting into larger future quotas — restraint must visibly pay the person who exercises it, or no one will.

Divide the cap into shares, but floor it. Give every active operator a guaranteed baseline allocation sized to keep a typical small boat above subsistence, and distribute only the remainder in proportion to recent participation. Make shares leasable but cap how much any operator or buyer may hold, and forbid trades that would drop a boat below its baseline. A pure tradable-quota market would let larger operators and processors buy out the smallest boats and quietly destroy the bottom quartile while aggregate numbers still look fine; the floor plus the holding cap is what prevents that. Aggregate income is protected because the total catch, though lower, is harvested from a recovering, higher-value stock of larger fish, and because effort costs fall once the race to fish before the others ends.

Cushion the transition with a dedicated fund. Finance it from a modest levy on the downstream processors and buyers (who depend on the stock continuing to exist) and any external recovery support, and use it to pay seasonal-closure stipends, buy back or convert excess gear, and support alternative income during the steepest part of the cut. The point is to absorb the short-term income dip so the floor holds and the <20% aggregate target is met across the cohort, not to subsidize overcapacity indefinitely; taper it as quotas rise.

Make the stock and the catch visible, and attach proportionate consequences. Require simple landing reporting at the processor point (the natural chokepoint — buyers already weigh fish), publish stock indicators and each village's catch against its cap, and use graduated penalties: a warning and small deduction for a first minor overage, escalating to share suspension for repeat or large violations. Proportionate, predictable, locally-witnessed enforcement sustains compliance far better than rare harsh crackdowns.

Guard against the regulator simply deferring again by not leaving the decision to the regulator alone. Stand up a co-management council with seats for the five villages, the processors, the regulator, and — critically — an independent stock scientist whose assessment sets the cap by a transparent rule rather than by negotiation. Publish the assessment, the cap formula, and council decisions. Independence of the science seat and transparency of the numbers are what stop the fleet from talking the cap back up year after year, which is exactly how this fishery arrived at overshoot.

Build in pre-collapse triggers. Because the dangerous transition may arrive before everyone agrees it is real, precommit to automatic precautionary cuts: if recruitment indicators, mean size, or CPUE fall below set warning bands in any season, the cap drops by a fixed step the following season without re-litigation, and reverses only when indicators recover. This preserves the intervention window instead of waiting for proof that arrives too late to act on.

Review and adjust the whole arrangement on a fixed cadence — annually for the cap, every few years for the rules — so the design tracks the stock rather than ossifying.

Final operating rule: each season, set the total catch from the independent assessment so the stock keeps growing toward its productive range; split that catch as a protected baseline for every boat plus a participation-weighted, transfer-limited remainder; cushion the cut from a buyer-funded transition fund; monitor at the dock with graduated sanctions; and if early-warning indicators worsen, cut the cap automatically and restore it only as the stock recovers — keeping every boat above subsistence while the population climbs back.

## Recommendation R3
Treat this as a shared stock that is being drawn down faster than it renews because each boat keeps the full value of its own catch while the cost of depletion is spread across everyone — so no appeal to restraint will hold unless the rules of access themselves change. The design has four interlocking parts: a science-anchored catch limit, a fair way to divide it, a transition cushion for the people the cut would otherwise sink, and a governance arrangement that the regulator cannot quietly hand back to the industry.

First, set a total allowable catch that is deliberately below the best estimate of maximum sustainable yield for the rebuild period — roughly a 25–30% reduction from current landings in year one — rather than merely trimming to the MSY point estimate. The stock estimate is uncertain and the collapse threshold is irreversible, so the limit must carry a buffer: underestimating renewal costs a little forgone catch, while overestimating it costs the whole fishery. Tie the limit to a written harvest-control rule: each year the limit is reset from the biologist's survey of catch-per-unit-effort and average fish size, and it tightens automatically — sharply — if the stock drifts toward the danger zone, loosening only as biomass climbs back into the productive range. This makes the limit a transparent function of stock condition, not an annual negotiation the strongest operators can win.

Second, divide the limit into per-boat shares rather than leaving a single pooled quota that triggers a race to fish it first. Freeze access to the current registered operators for the rebuild — no new entrants — so the burden of recovery is not used to displace the existing cohort. Allocate shares progressively: give every boat an equal baseline share sufficient for a viable trip, then distribute the remainder in proportion to recent catch history. This protects the smallest operators, because a flat percentage cut applied to everyone falls hardest on boats that were already near subsistence. Permit short-term leasing of unused share within the cohort so a fisher having a bad season can still earn, but prohibit permanent sale of shares to outside capital — unrestricted trading reliably consolidates the fishery into a few hands and pushes the bottom quartile out, which is precisely the outcome to avoid.

Third, build an explicit income floor and bridge. Fund it with a small levy on landings plus, where available, time-limited public or buyer-backed transition money, and use it three ways: a guaranteed minimum payment that tops up the bottom-quartile boats whenever their share-constrained income falls below a subsistence line; paid stewardship work during the low-catch years (survey assistance, gear retrieval, habitat and spawning-area protection) that keeps crews employed and the stock recovering at the same time; and modest buy-forward or storage arrangements with processors so the downstream buyers, who also depend on the stock, help finance the recovery rather than pressing for higher catches. The target is that aggregate cohort income stays within 20% of today even as total catch falls, because the cut is concentrated where it can be absorbed and the floor catches the rest.

Fourth — and this is what makes the rest credible — restructure who decides. The regulator has historically deferred to the industry, so do not rely on it writing stricter rules it will then enforce loosely. Place rule-making in a co-management board with elected seats from each of the five villages and the processors, but bound that board inside a scientific envelope it cannot vote away: the independent stock survey sets the outer limit on catch, and the board allocates and adapts within it. Keep the survey funded independently of the operators it constrains, publish a plain public dashboard of stock condition and every boat's catch against its share, and give competing voices — crew, the smallest operators, an outside scientific reviewer — standing to contest decisions before they take effect. Enforce with graduated, proportional sanctions: a first overage draws a warning and a deduction from next year's share; repeated or deliberate violation draws suspension. Add simple monitoring the community trusts — dockside landing records cross-checked against the survey — because limits that are not visibly observed will be ignored.

The operating rule, in one line: hold the catch below a conservatively buffered, survey-set limit and tighten it automatically as the stock nears danger; divide that limit progressively among the current boats with a guaranteed floor and stewardship pay for the weakest, allowing leasing but not sale of shares within the fleet; and vest the rules in a village-and-buyer board that may adjust allocation but never the science-set ceiling, under a public dashboard and graduated sanctions. Recover first by buffering against irreversibility, keep the fleet intact by spreading the cut progressively and cushioning the bottom, and protect both by making the ceiling something no single interest can quietly raise.

## Recommendation R4
The stock is being drawn down faster than it can renew because every operator captures the full value of each extra catch while sharing only a fraction of the cost of decline, and the body that could set limits has leaned on the people it should be restraining. With collapse four to seven years out and recovery from collapse far harder than prevention, the design must do three things at once: bind total catch below the renewal rate quickly, do so through an arrangement the fishers themselves accept and help run, and protect the weakest operators so the cure does not destroy the livelihoods it is meant to save.

Begin by closing the open door. Freeze the eligible fleet at the operators currently active and admit no new boats during recovery; this stops a race to grab catch before limits bite. Set a total allowable catch below the latest stock assessment's sustainable level. Because the stock is near a tipping point, front-load the restraint: an immediate cut of roughly a quarter to a third from current effort, deeper than steady-state harvesting would require, to pull the trajectory clearly away from the threshold. Crucially, do not lift this emergency cut simply because one season looks better. Define a separate, harder recovery test: catch-per-effort and average fish size must rise for several consecutive years before the limit is relaxed, and relaxation happens in graduated steps with monitoring for backsliding. Entering the danger zone is easy; leaving it safely takes sustained proof.

Allocate the catch not as individually tradable permits but as village-level shares, with a guaranteed minimum landing for every active boat. Tradable individual quotas would, in a poor heterogeneous fleet, consolidate into the hands of those with capital and push the smallest operators out — exactly the failure to be avoided. Village shares let each community manage its own allocation against local knowledge, and the per-boat floor keeps the bottom quartile above subsistence. Pair the catch limit with gear rules — minimum mesh size and a closed season over the spawning period — so the fleet stops removing juveniles; the shrinking average size is the signal that the stock's future breeders are being taken, and fixing that is as important as the headline tonnage.

Make compliance self-financing and self-policing. Levy a small charge on landings at the processor weigh-points, where fish already pass through a chokepoint, and use that revenue for two purposes: to fund monitoring at those existing points (no need for intrusive per-boat surveillance) and to capitalize a transition fund. Direct the fund at the operators with the least cushion — short-term income support, gear conversion grants, and seasonal alternative work — phased down only as catch rates and incomes recover. This is what keeps aggregate income within the twenty-percent band while restraint is heaviest, and it is targeted so the cohort average does not hide ruin in the bottom quartile.

Address the captured regulator structurally rather than by exhortation. Replace open discretion with a rule: the regulator retains formal authority to set the total catch but is bound to a published assessment and a pre-agreed harvest-control formula, so each year's limit follows transparently from the stock's measured state rather than from negotiation with the industry. Stand up a co-management board with seats for the five villages, the processors, the regulator, and an independent scientist, charged with allocation, dispute resolution, and graduated sanctions for violations — a warning, then a catch deduction, then suspension. Publish the assessment, the catch limit, landings, and board minutes. Visibility and a science-triggered rule are what make capture costly and the limits legitimate enough that fishers will accept enforcement, including enforcement of each other.

Tie everything to the resource's own condition. Re-survey the stock annually; let the harvest-control rule raise the catch as biomass recovers and tighten it automatically if recovery stalls or any year shows renewed decline, with the transition fund as the shock absorber during tight years.

The operating rule: each year, set the total catch from the current stock assessment via the published harvest-control formula; never relax the emergency cut until catch-per-effort and fish size have risen for several consecutive years; allocate by village share with a guaranteed per-boat floor; fund monitoring and a bottom-quartile-targeted transition fund from a landings levy; and keep the limit, the data, and the board's decisions public so neither the stock's decline nor the regulator's choices can again be hidden. Hold restraint until the stock is verifiably back in its productive range, then ease — slowly, and only on the evidence.
