Economic Valuation Methodology

Fisheries

The economic value of fisheries associated with both healthy and degraded coral reefs was assessed through an “effect on production” approach.

Fisheries Production

Previous studies of the productivity of coral reef fisheries in the Caribbean [1] and in Southeast Asia [2] provided guidelines for determining productivity declines on degraded coral reefs. Fisheries productivity on Caribbean coral reefs overall ranged between 0.5 and 5.0 mt/sq km/yr. Degraded coral reefs produced much less, averaging between 17 percent and 44 percent of the productivity of healthy reefs. For our estimate, we used the following productivity coefficients:

• For coral reefs regarded as healthy or classified as being under low threat, productivity of 4 mt/sq km/yr was used.
• For reefs under medium threat, productivity was assumed to decline to between 2.3 mt and 2.9 mt/sq km/yr.
• For reefs classified as under high threat, productivity of 0.7 and 1.7 mt/sq km/yr was used.

Degradation scenarios are for 2015. The Reefs at Risk Threat Index was used to estimate coral reef area in each threat category. By multiplying, we derived coral reef fisheries