Fish migrations represent some of the most fascinating animal movement patterns on the planet. Individuals are able to move between multiple ecosystem types (e.g. lakes, rivers, coastal ecosystems and open oceans), potentially playing a key role in nutrient transport as they travel, and acting as predators, competitors and prey to other species on the way. In a recent review published in Frontiers in Ecology and Evolution, Tamario and colleagues describe the threats currently faced by migrating fishes, and how the sustainable utilisation and protection of these species and their ecosystems can be achieved through informed management solutions.
Habitat modification, fragmentation and destruction of spawning and nursery habitats, pollution, and overexploitation are listed as primary threats to migrating fishes, and the authors discuss how each may impact the eco-evolutionary processes and diversity of these animals. Furthermore, Tamario and colleagues discuss the influence of environmental conditions on whether, why, where and when fishes migrate, and the potential for these behavioural patterns to vary under a shifting climate. Pressures arising from environmental makeovers (e.g. damming), management actions (e.g. the construction of fishways), as well as captive breeding and aquaculture are also considered.
By discussing the aforementioned threats facing migrating fishes across genetic, individual, population and ecosystem levels, the authors are able to succinctly outline promising future directions for research in this emerging field, and provide recommendations for the development of management strategies for migrating fishes in the face of current uncertainties.