Impacts of climate change on limnetic biodiversity and fisheries in Ontario and Quebec

气候变化将对加拿大湖泊的鱼类资源产生重大影响。然而，这些可能影响的确切性质将决定需要采取哪些步骤来避免由于当地关键物种的丧失而造成的重大经济和社会影响。这项赠款提案旨在为预测加拿大东部和中部内陆湖泊三种重要鱼类(大眼鱼、湖鲑鱼和小口鱼)的分布和种群数量的变化以及相关的生物多样性变化奠定科学基础。气候变化将对湖泊内不同水温的有效性产生不同的影响，这取决于湖泊的形态；即湖泊的深度和形状，以及浅水区的范围。这些相同的特征也决定了在气候变暖和干燥的情况下，湖泊表面面积的收缩程度。湖泊内热生境的变化对鱼类种群的影响将受到鱼类的运动行为及其与其他物种的相互作用的影响。要了解这些复杂的相互作用过程，需要研究整个湖泊的景观特征，并对湖泊内的鱼类种群进行定量建模研究。我们的提案将扩展并利用魁北克省和安大略省自然资源机构同时进行的湖泊测绘研究。这是预测鱼类数量变化的一个关键因素。预测三个重点鱼类物种未来丰度的模型将基于这些地图、湖泊内活动的经验测量、当前鱼类群落的地理比较，以及考虑到单个鱼类的大小分布、物种间相互作用的性质以及湖泊内不同热生境的安排的新一代数学模型。这将为在可能在不久的将来盛行的迅速变化的条件下管理商业和休闲渔业提供一个大大改进的基础。

Climate change will have major impacts on the fish stocks in Canada's lakes. However, the exact nature of these likely impacts will determine what steps are needed to avert major economic and social impacts due to local loss of key species. This grant proposal seeks to develop a scientific basis for predicting the changes in distributions and population sizes of three important fish species (walleye, lake trout, and smallmouth bass), and the associated changes in biodiversity for inland lakes in eastern and central Canada. Climate change will have different effects on the availability of different water temperatures within a lake, depending on the morphometry of the lake; i.e., its depth and shape, and the extent of shallow areas. These same characteristics also determine the extent of contraction in lake surface area under a warming and drying climate. The impact on fish populations due to the resulting changes in thermal habitat within a lake will be affected by the movement behaviour of the fish and their interactions with other species. Understanding these complicated, interacting processes requires studies of the characteristics of the entire set of lakes on the landscape as well as quantitative modeling studies of fish populations within lakes. Our proposal will expand upon, and make use o concurrent lake mapping studies by natural resource agencies in the provinces of Quebec and Ontario. This is a key element in any forecast of changing fish populations. The models to forecast future abundances of the three focal fish species will be based on these maps, empirical measurements of within lake movements, geographical comparisons of current fish communities, and a new generation of mathematical models that takes account of the distribution of sizes of individual fish, the nature of interactions between species, and the arrangement of different thermal habitats within the lake. This will provide a vastly improved basis for managing commercial and recreational fisheries under the rapidly changing conditions that are likely to prevail in the near future.