Evaluating the fishery and ecological consequences of the proposed North Sea multi-annual plan
Evaluating the fishery and ecological consequences of the proposed North Sea multi-annual plan
复制标题
评估拟议的北海多年期计划对渔业和生态的影响
作者：
S. Mackinson;M. Platts;Clement Garcia;C. Lynam
欧洲联盟委员会提出的北海多年期计划可能产生的影响是根据其在实现捕捞压力、物种生物量、渔业产量、关键物种的上岸价值和生态系统目标等管理目标方面可能产生的结果进行评价的。该方法适用于管理战略的评估程序，采用生态系统模型的北海及其渔业的经营模式。它以拟议计划的五个关键维度为例，确定了对其成功绩效至关重要的领域。绝大多数情况下，在执行弃鱼做法监管措施的备选方案中的选择，超过了与“相当好的产量”有关的范围内捕捞、生物量养护保障机制的适用方式和实现捕捞死亡率目标的时间框架有关的备选方案的影响。只有当种群生物量接近其参考点时，保障办法和渔捞死亡率幅度的影响才变得重要。考虑到更广泛的保护和生态系统的目标，第五个维度揭示了丢弃政策对保护物种有很大的影响，而且收获控制规则的类型可以发挥重要作用，限制风险的股票“刹车”早。然而，对渔业的后果是其生存能力的风险增加，从而暴露了平衡蓝色增长和加强保护的社会压力所面临的可持续性权衡。它还揭示了更广泛的生态系统的影响，强调底层和中上层领域之间的连接，因此，不能孤立地对待其他管理计划的底层NSMAP的重要性。当种群低于其生物量参考点时，低F策略导致更好的长期经济绩效，但对于始终高于生物量参考点的种群，高F策略导致更高的长期价值。Nephrops和Whiting经常对策略表现出矛盾的反应，因为它们的捕食者丰度的变化会影响它们的丰度和渔业的成功。
The possible impacts of the European Commission’s proposed North Sea Multi-Annual Plan are evaluated in terms of its likely outcomes to achieve management objectives for fishing pressure, species’ biomass, fishery yield, the landed value of key species and ecosystem objectives. The method applies management strategy evaluation procedures that employ an ecosystem model of the North Sea and its fisheries as the operating model. Taking five key dimensions of the proposed plan, it identifies those areas that are key to its successful performance. Overwhelmingly, choices in the options for the implementation of regulatory measures on discarding practices outweigh the effects of options related to fishing within ranges associated with ‘pretty good yield’, the way that biomass conservation safeguard mechanisms are applied and the timeframe for achieving fishing mortality targets. The impact of safeguard options and ranges in fishing mortality become important only when stock biomass is close to its reference points. The fifth dimension–taking into account wider conservation and ecosystem objectives—reveals that discard policy has a big impact on conservation species, but also that the type of harvest control rule can play an important role in limiting risks to stocks by ‘applying the brakes’ early. The consequences to fisheries however is heightened risk to their viability, thus exposing the sustainability trade-offs faced with balancing societal pressures for blue growth and enhanced conservation. It also reveals the wider ecosystem impacts that emphasise the connectivity between the demersal and pelagic realms, and thus, the importance of not treating the demersal NSMAP in isolation from other management plans. When stocks are below their biomass reference points, low F strategies lead to better long term economic performance, but for stocks consistently above biomass reference points, high F strategies lead to higher long term value. Nephrops and whiting often show contradictory responses to the strategies because changes in their predators abundance affects their abundance and success of their fisheries.