Hastings Alan, Gaines Steven D, Costello Christopher
Department of Environmental Science and Policy, University of California, Davis, CA 95616;
Bren School of Environmental Science & Management, University of California, Santa Barbara, CA 93106.
Proc Natl Acad Sci U S A. 2017 Aug 22;114(34):8927-8934. doi: 10.1073/pnas.1705169114. Epub 2017 Aug 9.
Management of the diverse fisheries of the world has had mixed success. While managing single species in data-rich environments has been largely effective, perhaps the greatest challenge facing fishery managers is how to deal with mixed stocks of fish with a range of life histories that reside in the same location. Because many fishing gears are nonselective, and the costs of making gear selective can be high, a particular problem is bycatch of weak stocks. This problem is most severe when the weak stock is long-lived and has low fecundity and thus requires a very long recovery time once overfished. We investigate the role that marine reserves might play in solving this challenging and ubiquitous problem in ecosystem-based management. Evidence for marine reserves' potential to manage fisheries in an ecosystem context has been mixed, so we develop a heuristic strategic mathematical model to obtain general conclusions about the merits of managing multispecies fisheries by using reserves relative to managing them with nonspatial approaches. We show that for many fisheries, yields of strong stocks can be increased, and persistence of weak stocks can be ensured, by using marine reserves rather than by using traditional nonspatial approaches alone. Thus, reserves have a distinct advantage as a management tool in many of the most critical multispecies settings. We also show how the West Coast groundfish fishery of the United States meets these conditions, suggesting that management by reserves may be a superior option in that case.
世界上各种渔业的管理成效参差不齐。虽然在数据丰富的环境中对单一物种进行管理大多是有效的，但渔业管理者面临的最大挑战或许是如何应对生活史各异却栖息在同一区域的混合鱼类种群。由于许多渔具并无选择性，且使渔具具有选择性的成本可能很高，一个特别的问题是副渔获物中出现脆弱种群。当脆弱种群寿命长、繁殖力低，因而一旦过度捕捞需要很长时间才能恢复时，这个问题就最为严重。我们研究了海洋保护区在基于生态系统的管理中解决这一具有挑战性且普遍存在的问题时可能发挥的作用。关于海洋保护区在生态系统背景下管理渔业的潜力的证据并不一致，因此我们开发了一个启发式战略数学模型，以得出关于利用保护区管理多物种渔业相对于采用非空间方法管理的优点的一般性结论。我们表明，对于许多渔业来说，通过使用海洋保护区而非仅使用传统的非空间方法，可以提高优势种群的产量，并确保脆弱种群的存续。因此，在许多最关键的多物种渔业环境中，保护区作为一种管理工具具有明显优势。我们还展示了美国西海岸底层鱼类渔业是如何符合这些条件的，这表明在这种情况下，通过保护区进行管理可能是一个更好的选择。
