A novel method for long-term ventilation recording of prawns and shrimps (Decapoda: Dendrobranchiata, Caridea) across molting cycle

We developed a novel method for real-time recording of scaphognathite pumping in prawns using a 27-gauge, stainless-steel injection needle bent at three right angles as a recording electrode. This electrode was implanted into the inner side of the carapace at the anterior end of the gill chamber. During pumping, the small frictional contact between the scaphognathite and the electrode generated electrical signals that served as indicators of scaphognathite activity. The electrical signals accurately differentiated between forward and reverse pumping and the various scaphognathite pumping patterns reported in the literature. The electrode and the wire did not interfere with the prawns’ movements or molting, enabling prolonged recording periods, including across molting cycles.