Why Do Sturgeon Jump? New Technology to Address an Ancient Question

Many sturgeon species jump, and proposed reasons for jumping have included the removal of parasites, signaling as part of nuptial behavior, to help shed eggs during spawning, or as a form of communication to maintain group cohesion. These ideas have been difficult to test, in part because of an inability to monitor the fine-scale behavior of individual fish. This can now be achieved through the use of acceleration data loggers (ADLs) that continuously record the fish’s tailbeat frequency and amplitude, swimming depth, and temperature at sub-second intervals. We attached ADLs to Gulf sturgeon, Acipenser oxyrinchus desotoi, in the Suwannee River, FL where jumping behavior has led to collisions with boaters, occasionally producing serious injuries.  ADL data revealed several jumps and other behaviors associated with them. We present preliminary findings from these data and suggest that one function of jumping may be to modulate air volume in the swim bladder to enhance buoyancy control in these physostomous fish.