Bursting modes, which are identified as bounce precession frequency fishbone modes, are observed on a low aspect ratio tokamak, the national spherical torus experiment (Ono M. et al 2000 Nucl. Fusion40 557). They are predicted to be important in high current, low shear discharges with a significant population of trapped particles with a large mean bounce angle, such as produced by near tangential beam injection into a small aspect ratio device. Such a distribution is often stable to the usual precession-resonance fishbone mode. These modes could be important in ignited plasmas, driven by the trapped alpha particle population.