Ventilatory responses to ambient oxygen in stressed and fully settled shore crabs Carcinus maenas (L.)

Scaphognathite activity and ventilatory responses to changes of ambient oxygen have been studied in stressed and fully settled crabs, Carcinus maenas (L.). Compared with resting, fully settled animals, resting stressed crabs exhibited very high values of scaphognathite beat frequency, negative hydrostatic pressure in the gill chamber and amount of time spent ventilating, suggesting a much elevated ventilatory flow rate. Unlike fully settled animals, stressed crabs did not show significant ventilatory responses to changes of ambient oxygenation.