FA-65564 / Ecological population dynamics / Member archive

Schaefer surplus-production harvest reference points: collapse threshold · case 04

Excessive effort yields negative biomass and negative catch.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

MSY = rK/4 at B=K/2 and E_msy = r/(2q); equilibrium biomass under effort E is K(1-qE/r) when qE<r else 0; yield = qEB; status 'overfished' when E>E_msy, 'at-msy' when equal, else 'sustainable'; return [MSY, Bmsy, Emsy, B, yield, status] rounded; None for invalid inputs.

Why this case matters

Population projections set harvest quotas, conservation status and pest-control timing; a wrong update order, boundary or rate conversion silently changes management advice.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: collapse effort	`[150.0, 1500.0, 100.0, -1500.0, -450.0, "overfished"]`	`[150.0, 1500.0, 100.0, 0.0, 0.0, "overfished"]`	Failed

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