Skin and Bones, Sinew and Gristle: the Mechanical Behavior of Fish Skeletal Tissues

Publisher Summary This chapter reviews the functional capacities of fish skeletal structures and tissues, as those capacities have been determined by the measurement of mechanical properties under life‐like loading conditions. The mechanical workings of fishes have been approached in a two-pronged framework, with (1) muscle as the engine of motion and force and (2) water as the external source of resistance and purchase. The interaction of muscle and water certainly lays the foundation for behaviors as diverse as swimming, breathing, and feeding, but the interaction between them is only part of the picture. Understanding fishes as mechanical actors requires study of a third factor: the skeleton. This chapter defines skeleton broadly to include connective tissues such as tendon, ligament, cartilage, and bone that have a large component of extracellular collagen fibers. By measuring the mechanical properties of skeletal tissue and structures, one can begin modeling a few mechanical behaviors of a few species and understanding the integrated function of muscle, water, and skeleton. Even though the skeletal systems of fishes are complicated, analysis is helped by the often clear connection between skeletal structure and mechanical function, particularly when that correlation has convergently evolved. A clear causal connection is easily seen between the teeth and prey processing in heterodontid sharks and in sparid fish: their robust molariform teeth permit the crushing of hard prey such as mollusks and echinoderms.