Ecol Appl. 2016 Jun;26(4):1086-97. doi: 10.1890/14-1771.
Recreational fishing effort varies across complex inland landscapes (e.g., lake-districts) and appears influenced by both angler preferences and qualities of the fishery resource, like fish size and abundance. However, fish size and abundance have an ecological trade-off within a population, thereby structuring equal-quality isopleths expressing this trade-off across the fishing landscape. Since expressed preferences of recreational anglers (i.e., site-selection of high-quality fishing opportunities among many lakes) can be analogous to optimal foraging strategies of natural predators, adopting such concepts can aid in understanding scale-dependence in fish-angler interactions and impacts of fishing across broad landscapes. Here, we assumed a fish supply-angler demand equilibria and adapted a novel bivariate measure of fishing quality based on fish size and catch rates to assess how recreational anglers influence fishing quality among a complex inland landscape. We then applied this metric to evaluate (1) angler preferences for caught and released fish compared to harvested fish, (2) the nonlinear size-numbers trade-off with uncertainty in both traits, and (3) the spatial-scale of the equilibria across 62 lakes and four independent management regions in British Columbia's (BC) rainbow trout Oncorhynchus mykiss fishery. We found anglers had low preference for caught and released fish (~10% of the value compared to harvested fish), which modified anglers' perception of fishing quality. Hence, fishing quality and angler effort was not influenced simply by total fish caught, but largely by harvested fish catch rates. Fishing quality varied from BC's northern regions (larger fish and more abundant) compared to southern regions (smaller fish and less abundant) directly associated with a 2.5 times increase in annual fishing effort in southern regions, suggesting that latent fishing pressure can structure the size-numbers trade-off in rainbow trout populations. The presence of two different equal-quality isopleths suggests at least two effective landscapes support co-occurring ideal free distributions of recreational fishing effort in BC's rainbow fishery. Anglers' expressed preferences among lakes interacted with density dependent growth and survival within lakes to structure a size-numbers trade-off influencing how anglers perceive fishing quality and, ultimately, distribute across complex inland landscapes.
休闲钓鱼的努力程度在复杂的内陆景观中（例如，湖区）有所不同，并且似乎受到钓鱼者偏好和渔业资源质量的影响，例如鱼类的大小和丰度。然而，鱼类的大小和丰度在种群中存在生态上的权衡，从而构建了等质量的等距线，以表达这种权衡在整个渔业景观中的表现。由于休闲钓鱼者的表达偏好（即在许多湖泊中选择高质量的钓鱼机会的地点选择）可以类似于自然捕食者的最优觅食策略，因此采用这种概念可以帮助理解鱼类与钓鱼者之间相互作用的尺度依赖性以及在广阔景观中钓鱼的影响。在这里，我们假设鱼类供应与钓鱼者需求的平衡，并采用一种新颖的基于鱼类大小和捕获率的双变量捕鱼质量衡量标准，以评估休闲钓鱼者如何在复杂的内陆景观中影响捕鱼质量。然后，我们使用该指标评估：（1）与捕捞鱼相比，钓鱼者对被捕获和放生的鱼的偏好，（2）在两个特征都存在不确定性的情况下，大小数量的非线性权衡，以及（3）在不列颠哥伦比亚省（BC）虹鳟鱼 Oncorhynchus mykiss 渔业的 62 个湖泊和四个独立管理区域中，平衡的空间尺度。我们发现，钓鱼者对被捕获和放生的鱼的偏好较低（与捕捞鱼相比，仅为其价值的 10％），这改变了钓鱼者对钓鱼质量的看法。因此，钓鱼质量和钓鱼者的努力程度不仅受捕获的鱼总量的影响，而且还主要受捕捞鱼的捕获率的影响。从不列颠哥伦比亚省的北部地区（鱼更大，更丰富）到南部地区（鱼更小，更稀缺），钓鱼质量有所不同，这与南部地区每年钓鱼努力的增加有直接关系，这表明潜在的钓鱼压力可以构造虹鳟鱼种群中的大小数量权衡。两个不同的等质量等距线的存在表明，至少有两个有效的景观支持不列颠哥伦比亚省虹鳟渔业中休闲钓鱼努力的理想自由分布的共存。钓鱼者在湖泊之间的表达偏好与湖泊内的密度依赖性生长和生存相互作用，构造了一个大小数量的权衡，影响了钓鱼者对钓鱼质量的看法，最终在复杂的内陆景观中进行了分布。
