Evidence of market-driven size-selective fishing and the mediating effects of biological and institutional factors
Evidence of market-driven size-selective fishing and the mediating effects of biological and institutional factors
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DOI：
10.1890/12-1196.1
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发表时间：
2013-06-01
影响因子：
5
通讯作者：
Leslie, Heather M.
中科院分区：
文献类型：
--
作者：
Reddy, Sheila M. W.;Wentz, Allison;Leslie, Heather M.
市场需求常常被忽视或被认为会导致资源的减少。然而，人们对市场需求如何影响特定环境下的自然资源，或生物或制度因素的中介作用知之甚少。在这里，我们通过考察墨西哥拉巴斯周围的太平洋红鲷鱼（Lutjanus peru）渔业来调查这个问题，那里的中型或“盘子大小”的鱼以高价出售给餐馆。如果对盘子大小的鱼的较高需求增加了最小（新入尺寸级别）和最大（最多产）鱼的相对丰度，这可能是增加种群和渔民收入的市场机制。我们对此进行了测试 通过使用价格和渔获量的每日记录来估计价格对不同尺寸级别的渔获量分布的影响来提出假设。我们将这种经济选择模型的预测与分阶段渔业模型联系起来，以估计对种群和收获收入的影响。我们发现，盘状鱼的供应量增加了 6%，而由于盘状鱼的溢价 13%，大型鱼的供应量下降了 4%。这种以市场为导向的尺寸选择增加了收入 （14%），但鱼类总生物量减少（-3%）。然而，当市场驱动的规格选择与有限的制度限制相结合时，鱼类生物量（28%）和渔民收入（22%）都会增加。这些结果表明，市场需求对生物种群和人类行为影响的方向和程度可能取决于生物属性和制度约束。渔业管理可以通过实施基于规模的措施来利用这些条件效应 当经济和制度激励将增强合规性时，如我们在此描述的情况，或通过为现有法规创造增强合规性的条件，则制定法规。
Market demand is often ignored or assumed to lead uniformly to the decline of resources. Yet little is known about how market demand influences natural resources in particular contexts, or the mediating effects of biological or institutional factors. Here, we investigate this problem by examining the Pacific red snapper (Lutjanus peru) fishery around La Paz, Mexico, where medium or "plate-sized'' fish are sold to restaurants at a premium price. If higher demand for plate-sized fish increases the relative abundance of the smallest (recruit size class) and largest (most fecund) fish, this may be a market mechanism to increase stocks and fishermen's revenues. We tested this hypothesis by estimating the effect of prices on the distribution of catch across size classes using daily records of prices and catch. We linked predictions from this economic choice model to a staged-based model of the fishery to estimate the effects on the stock and revenues from harvest. We found that the supply of plate-sized fish increased by 6%, while the supply of large fish decreased by 4% as a result of a 13% price premium for plate-sized fish. This market-driven size selection increased revenues (14%) but decreased total fish biomass (-3%). However, when market-driven size selection was combined with limited institutional constraints, both fish biomass (28%) and fishermen's revenue (22%) increased. These results show that the direction and magnitude of the effects of market demand on biological populations and human behavior can depend on both biological attributes and institutional constraints. Fisheries management may capitalize on these conditional effects by implementing size-based regulations when economic and institutional incentives will enhance compliance, as in the case we describe here, or by creating compliance enhancing conditions for existing regulations.