An analytical and hypothesis-driven approach to elasmobranch movement studies.

The study of elasmobranch movements has increased steadily since the early 1970s. A great deal is now known about the horizontal and vertical movements of many elasmobranch species over multiple spatial and temporal scales. These studies illustrate that many species share certain behaviours such as diel shifts in habitat (both horizontal and vertical), continuous yo-yo bounce diving and in many cases, seasonal migrations. Hypothesis-driven studies explaining these behaviours or utilizing an eco-physiological predictive framework are, however, relatively rare. In this review, the descriptive and hypothesis-driven studies of elasmobranch movements are discussed, in addition to some of the analytical tools that can be used to generate or test predictions. There are many tools and analytical techniques available which are not currently being utilized for most studies of elasmobranch movements. With the constant improvement in technology and statistical techniques, the development of hypothesis-driven studies of elasmobranch movements should continue to increase.