A Conceptual Model for the Regulation of Cardiac and Ventilatory Activity of the Portunid Crab, Portunus pelagicus (Linnaeus)

Portunus pelagicus in common with a number of large decapod crustaceans displays a discontinuous pattern of cardiac activity and ventilation (pausing or pause/pulsing). Energy saved by pulsed activity can be explained by reference to non-linear arterial analogues where decreased impedance to pulsatile flow occurs at or above a resonant frequency. A "two-position regulator" optimal control model is proposed to maximize cardiac pump efficiency by optimising the duration of the pulse at or above this resonant frequency. Simulations of the control model are consistent with parameters observed from P. pelagicus.