Ocean fish populations are a vital renewable resource for human populations, providing food,employment and recreation, as well as contributing to global biodiversity. Unfortunately, due to overfishing, environmental degradation, climate change and other stressors, many fish stocks worldwide are in considerable decline.
Biological overfishing occurs when fishing rates exceed population growth rates. The resulting declines in fish populations can impact the economy at large. This study analyzes one important component of the costs of overfishing: forgone revenues from lost commercial fisheries harvests due to years of continuedstock depletion, or historic overfishing. It estimates the present annual forgone revenue of overfishing for three regions in the United States: New England, the South Atlantic and the Gulf of Mexico. These regions were chosen for analysis because they are grappling with the effects of historic overfishing and therefore have a significant number of overfished stocks. The 20 stocks included in this analysis are federally managed stocks particular to each region that are included in the Fish Stock Sustainability Index and are currently classified by the National Marine Fisheries Service as "overfished." A stock that is classified as overfished is defined as having a biomass level below a biological threshold specified in its fishery management plan.
Overfishing means fewer fish are available to catch in future years. The annual forgone revenue of historic overfishing, therefore, is an estimate of the value of lost catch in a given year due to overfishing. To arrive at the catch loss for each fishery, we first estimated the potential landings of each overfished stock as if it were at healthy levels, and compared those estimates directly to current landings values. We measured potential landings for each fish stock on the basis of optimal yield, and examined four approximations of optimal yield. Our estimates of commercial catch losses are for 2009, the most recent year for which all necessary data were available.
Based on our estimates, the aggregate catch loss summed over all three regions in 2009 was $164.2 million. Under a less-conservative approximation of optimal yield, commercial catch loss across all three regions in 2009 was estimated at $222.5 million. Across all three regions, we demonstrated that only 20 to 29 percent of potential landings in 2009 were realized in actual landings. We found the commercial catch loss ($149 million) to be greatest in New England, where there are more overfished species than in any other region in the United States. In the Gulf of Mexico and South Atlantic regions, where large catch allocations are apportioned to recreational fishing, and therefore not accounted for in this analysis, commercial catch losses were lower but still significant. Commercial catch loss in the Gulf of Mexico and the South Atlantic regions were $12.3 million and $2.9 million, respectively.
Our estimates of losses resulting from historic overfishing apply to commercial landings only, and do not account for the backward-linked economic impacts of commercial harvest, nor the forward-linked economic activity that would have resulted from the processing and retail sale of these potential catches. Additionally, there are further economic losses beyond the commercial sector in other industries, such as recreational fishing, and there are costs associated with negative impacts to food security, biodiversity and other ecosystem services that are not addressed in this analysis. Commercial catch losses are onesignificant component of the total economic costs of overfishing. Estimates of commercial catch loss we find in this study provide a strong economic argument in support of maintaining healthy fish populations and avoiding delays in rebuilding stocks currently subject to overfishing and/or classified as overfished.