Roughgarden J, Smith F
Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
Proc Natl Acad Sci U S A. 1996 May 14;93(10):5078-83. doi: 10.1073/pnas.93.10.5078.
With the collapse of fisheries in many parts of the world causing widespread economic harm, attention is focused on a possible cause and remedy of fishery collapse. Economic theory for managing a renewable resource, such as a fishery, leads to an ecologically unstable equilibrium as difficult to maintain as balancing a marble on top of a dome. A fishery should be managed for ecological stability instead--in the analogy, as easy to maintain as keeping a marble near the base of a bowl. The goal of ecological stability is achieved if the target stock is above that producing maximum sustainable yield and harvested at less than the maximum sustainable yield. The cost of managing for ecological stability, termed "natural insurance," is low if the fishery is sufficiently productive. This cost is shown to pay for itself over the long term in a variable and uncertain environment. An ecologically stable target stock may be attained either with annually variable quotas following current practice or, preferably, through a market mechanism whereby fish are taxed at dockside if caught when the stock was below target and are untaxed otherwise. In this regulatory environment, the goal of maximizing short-term revenue coincides with the goal of ecological stability, thereby also maximizing long-term revenue. This new approach to fishery management is illustrated with the recently collapsed Newfoundland fishing industry. The Newfoundland cod fishery is expected to rebuild to an ecologically stable level in about 9 years and thereafter support an annual harvest of about 75% of the 1981-1990 average.
随着世界许多地区渔业的崩溃造成广泛的经济损害，人们将注意力集中在渔业崩溃的可能原因及补救措施上。管理可再生资源（如渔业）的经济理论会导致一种生态不稳定的平衡，这种平衡难以维持，就像在圆顶上平衡一颗弹珠一样。相反，渔业管理应着眼于生态稳定性——用这个比喻来说，就像把弹珠保持在碗底附近一样容易维持。如果目标种群数量高于产生最大可持续产量的水平，并以低于最大可持续产量的水平进行捕捞，就能实现生态稳定的目标。如果渔业具有足够的生产力，那么为实现生态稳定性进行管理的成本（称为“自然保险”）就很低。事实证明，在一个多变且不确定的环境中，这笔成本从长期来看是能够自给自足的。通过遵循当前做法采用年度可变配额，或者更可取的是，通过一种市场机制，即在种群数量低于目标水平时捕捞的鱼在码头征税，否则不征税，都可以实现生态稳定的目标种群数量。在这种监管环境下，使短期收入最大化的目标与生态稳定的目标相契合，从而也能使长期收入最大化。这种渔业管理的新方法通过最近崩溃的纽芬兰渔业得到了说明。纽芬兰鳕鱼渔业预计将在大约9年内恢复到生态稳定水平，此后每年的捕捞量将维持在1981 - 1990年平均水平的约75%。
