Rebuilding depleted fish stocks: the good, the bad, and, mostly, the ugly

Recovery of depleted fish populations has become an important theme in national and international negotiations and commitments regarding sustainability. Although up to 63% of fish stocks worldwide may be in need of rebuilding, only 1% are currently classified as rebuilding, and fewer yet have been rebuilt. Recent history in stock recovery provides a rich source of examples of rebuilding plans across a spectrum of execution (good, bad, ugly, and in progress). Of 24 depleted stocks with formal plans that successfully reduced the fishing mortality, all but one exhibited signs of recovery. The median instantaneous annual rate of biomass recovery (0.16) was similar to the rate of depletion (-0.14) experienced, but stocks with more vulnerable life histories recovered substantially slower than they had been depleted. Most successful rebuilding programmes have incorporated substantial, measurable reductions in fishing mortality at the onset, rather than relying on incremental small reductions over time. A particularly vexing issue is the differential pace of recovery among relatively productive and unproductive components of mixed-species fisheries. Rebuilding the majority of stocks classified worldwide as overfished will take a more effective, consistent, and politically supported stock-recovery paradigm, if society is eventually to meet its articulated sustainability goals for global fisheries.