Advancing fisheries analysis through the application of ecological foraging principles

在公众舆论中，渔业的健康通常等同于保持甚至增加渔获量。然而，过去几十年加拿大鲱鱼和鳕鱼的经验告诉我们，这并不总是正确的。维持我们收成的潜在鱼类种群并不总是很好地反映在捕获的鱼类中。渔业科学向我们展示了许多种群“崩溃”的例子，因为没有足够快地发现持续的下降期。渔业本身的性质是一个研究较少的影响，可以掩盖人口下降。我们的商业捕鱼机非常擅长他们所做的。因此，它们的渔获量（和渔获量率）往往保持在较高水平，即使鱼的数量最初有所下降。然而，来自商业渔业的信息仍然是我们许多人口估计的基础。 拟议的方案质疑了许多经典渔业分析的观点。传统的分析是根据捕捞活动的数量来定义渔获量：单位努力量的渔获量。然而，在业绩计量中包括努力量可能会掩盖渔获量没有与努力量成比例增加的情况。我们将用统计方法测试这些影响，研究整个船队和单个船只的影响。传统分析还假定，预期物种（目标）的CPUE是丰度变化的最佳指标。然而，这是CPUE的变化应该由fisher行为缓冲的时候。我和我的学生将在人口估计的目标期之外测试CPUE的有效性。在传统的分析中，很少考虑邻近种群之间的渔民移动的影响。我们将采用我们实验室最近的理论发展，将生态觅食原则与渔业活动相结合：渔业等径线。这将把邻近种群组成部分之间以及它们之间沿着边界的船只移动情况纳入渔业评估。所有这些行为偏差将被用来改变在最先进的人口评估模型中使用努力的方式。最后，我们将测试和模拟海上船只（船队内的网络）与底层鱼类分布之间的变化关系。这将为今后在人口估计中纳入不断变化的船队结构奠定基础。 拟议的研究计划将改变在资源评估中使用捕捞努力量。这项研究将提供一个动态的捕捞努力量的视角，这将提高鱼类种群估计的准确性，并减少过去导致渔业危机的CPUE数据的误解风险。

In public opinion, the health of a fishery is usually equated to maintaining or even increasing catches. However, experiences with Canadian herring and cod in past decades have shown us that this is not always true. The underlying fish populations that sustain our harvests are not always well reflected by the fish that are caught. Fisheries science has shown us many examples where populations “collapse” because sustained periods of decline were not detected quickly enough. One of the less studied influences that can mask population decline is the nature of fishing itself. Our commercial fish harvesters are very good at what they do. As a result, their catches (and catch rates) often remain high, even as fish numbers initially decline. Yet information from commercial fisheries is still the foundation of many of our population estimates. The proposed program questions many of the perspectives of classical fisheries analysis. Traditional analyses define catch rate in terms of the amount of fishing activity: catch per unit effort (CPUE). However, including effort in the measure of performance can mask catches that do not increase in proportion to effort. We will test for these effects with statistical methods looking at effects within entire fleets and at the level of individual vessels. Traditional analyses also assume that the CPUE of the intended species (the target) is the best indicator of changing abundances. However, this is the time when changes in CPUE should be buffered by fisher behaviour. My students and I will test the effectiveness of CPUE from outside of targeting periods in population estimates. The implications of fisher movement between neighboring populations are seldom considered in classical analyses. We will employ a recent theoretical development in our lab that unites ecological foraging principles to fishing activities : fisheries isodars. This will incorporate vessel movements into fishery assessments among neighboring population components and along the boundaries between them. All of these behavioural biases will be used to change the way that effort is used in state-of-the-art population assessment models. Finally, we will test for and simulate changing associations among vessels at sea (networks within fleets) in relation to the underlying fish distributions. This will lay the foundation for the future incorporation of changing fleet structure in population estimates. The proposed research program will transform the use of fishing effort in stock assessments. The research will provide a dynamic perspective of fishing effort that will improve the accuracy of fish population estimates and reduce the risk of misinterpretation of CPUE data that has contributed to fishery crises in the past.