Collaborative Research: RUI: How energy economy and muscle properties shape fish swimming strategies in the field

The University Of Montana-Western, Dillon MT

Investigators

Abstract

Fish are important components of freshwater and marine ecosystems, are economically important through commercial fisheries and aquaculture, and have further socio-economic value in the form of recreational fishing. Relatively little is known about the details of fish behavior in the field. A major goal of the project is to develop low-cost underwater video techniques that allow analysis of fish swimming behavior. This approach has revealed that some fish use intermittent propulsion while swimming: a swimming mode where short series of tail beats are interrupted by gliding. Information from field swimming videos will be combined with physiological techniques in the lab to measure swimming energy costs and muscle properties. The researchers can then explore the potential advantages of this swimming style, for example we predict that intermittent swimming will reduce energy costs. Energy economy is biologically important for many animals, and low-cost propulsive strategies may also inform the design and operation of underwater vehicles. Improved knowledge of fish behavior and physiology can also inform management of fish habitats, commercial and recreational fisheries, and aquaculture facilities, as well as improve the design of engineered structures with which fish interact such as fish ladders and spillways. Additionally, the project will broaden the participation of underrepresented groups in STEM fields by providing research training opportunities for several undergraduate and high school students. To fully understand the links between locomotion and fitness, the investigators require information on the following: 1) how animals move in their habitats, 2) the factors that underlie the observed patterns of movement, and 3) how these factors affect the performance metrics, such as energy economy, that impact fitness. Field swimming performance data recently obtained by the Principal Investigators indicate that bluegill sunfish use an intermittent propulsive strategy for swimming, a behavior rarely observed under laboratory conditions. Intermittent propulsion is widely used during flight and may also be common during swimming, although detailed field data are scarce. Given their accessibility in their habitat, and suitability for behavioral and physiological data collection in the lab, bluegills are an ideal model system for exploring the potential benefits of intermittent propulsion during fish swimming. The project will use 3D underwater videography to provide the most detailed analysis of fish swimming performance in the field yet attempted. These data will be integrated with laboratory measurements of muscle contractile performance to quantify the potential muscle level constraints that favor intermittent propulsive strategies, and to test long-standing hypotheses regarding the potential energetic advantages of intermittent propulsion in swimming fish. The resulting data will be broadly applicable in interpreting fish behavior in the field and will inform laboratory approaches to ensure performance is measured in ways relevant to organismal fitness. Additionally, the project will provide research training opportunities for several undergraduate and high school students who are recruited from populations that are traditionally underrepresented in STEM fields. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.