Department of Wildlife, Fisheries, and Aquaculture, Mississippi State University, Mississippi, Mississippi State, United States of America.
National Warmwater Aquaculture Center, Mississippi State University, Stoneville, Mississippi, United States of America.
PLoS One. 2020 Feb 26;15(2):e0229402. doi: 10.1371/journal.pone.0229402. eCollection 2020.
Piscivorous avian species are the main source of catfish depredation at aquaculture facilities in Mississippi, resulting in the economic loss of millions of dollars every year. Most notable of these avian species are the double-crested cormorant (Phalacrocorax auritus), great blue heron (Ardea herodias), and great egret (A. alba). Understanding why these species select specific ponds can increase management efficiency directed at avian dispersal and provide insight into their decision making with respect to foraging behavior. We collected species presence data on catfish ponds by flying 35 surveys from October through April of 2015-2017, during which an average of 973 catfish ponds were observed each year. We collected data associated with each pond's physical surroundings and contents and used occupancy modeling to determine their influence on avian occupancy probability. We also collected data associated with stocking practices and catfish health on a subset of ponds, and constructed resource selection functions to model their influence on avian presence. Pond area was positively related to occupancy probability of each species. Cormorant occupancy increased as pond distance from forest cover and activity centers, such as workshops and offices, increased. Distance to nearest activity center was positively related to egret occupancy, while distance to nearest forested area was negative. Ponds containing diseased catfish had an increased probability of use by both herons and egrets. In general, cormorants and egrets showed greater probability of use on the periphery of pond clusters. The abundance of catfish was positively related to cormorant and heron presence. Specific pond contents and characteristics influenced presence of each avian species in different ways, including fish species cultured, production methods, pond systems, and fish types. Many pond selection relationships were species-specific, illustrating inherent differences in their foraging ecology. Consequently, specific management actions aimed to reduce avian presence will depend on the targeted species.
食鱼鸟类是密西西比州水产养殖设施中鲶鱼被捕食的主要来源，每年造成数百万美元的经济损失。这些鸟类中最著名的是双冠鸬鹚（Phalacrocorax auritus）、大蓝鹭（Ardea herodias）和大白鹭（A. alba）。了解这些物种为什么选择特定的池塘，可以提高针对鸟类扩散的管理效率，并深入了解它们在觅食行为方面的决策过程。我们通过在 2015 年至 2017 年 10 月至 4 月期间进行的 35 次飞行调查，收集了鲶鱼池塘的物种存在数据，平均每年观察到 973 个鲶鱼池塘。我们收集了与每个池塘物理环境和内容相关的数据，并使用占有模型来确定它们对鸟类占有概率的影响。我们还收集了与池塘养殖实践和鲶鱼健康相关的数据，并构建了资源选择函数来模拟它们对鸟类存在的影响。池塘面积与每个物种的占有概率呈正相关。随着池塘与森林覆盖和活动中心（如车间和办公室）之间的距离增加，鸬鹚的占有概率增加。到最近活动中心的距离与白鹭的占有概率呈正相关，而到最近森林地区的距离则呈负相关。患有疾病的鲶鱼池塘更有可能被苍鹭和白鹭使用。一般来说，鸬鹚和白鹭在池塘群的外围更有可能被使用。鲶鱼的丰度与鸬鹚和苍鹭的存在呈正相关。特定的池塘内容和特征以不同的方式影响每种鸟类的存在，包括养殖的鱼类种类、生产方法、池塘系统和鱼类类型。许多池塘选择关系是特定于物种的，说明了它们在觅食生态方面的固有差异。因此，旨在减少鸟类存在的具体管理措施将取决于目标物种。
