The use of stimulants as an aid to wean fishery caught blackfoot abalone (Haliotis iris) to artificial food

摘要

Abalone use a combination of tactile and chemosensory feeding cues to detect suspended seaweed in their natural environment. However, in a commercial situation, adult abalone (Haliotis iris) caught for broodstock or pearling, show reluctance to start feeding on stationary artificial food, they may lapse into a starvation phase that can last several weeks. Subtidal adult H. iris (125 mm shell length) were collected during autumn, winter, spring, and summer from Banks Peninsula, Canterbury and held at Pendarves Abalone Farm Ltd. (South Island, New Zealand). Abalone were divided randomly into two groups. One group was offered a commercial pellet diet together with small quantities (0.03-0.05g dry weight L~(-1)) of suspended seaweed particles (Gracilaria spp.) to test its potential as a tactile phagostimulant. The other group (nonstimulant control) were supplied with the same commercial diet without the algal stimulant Each group consisted of three replicate vessels containing three individuals. Abalone behavioral responses and ingestion rates were monitored in both groups over a 3-wk period. Abalone in the stimulant experiment exhibited a typical feeding posture almost immediately, were more alert, and engaged in a greater range of feeding activities than the abalone that had been supplied with commercial food only. Those abalone without access to the algal stimulant remained either quiescent or alert in most seasons. Feeding activity of abalone in the stimulant treatment was significantly higher(P < 0.05) as compared with abalone from the nonstimulant control for all seasons except winter. Also, abalone consumed significantly more artificial food when tactile stimulants were present during autumn and winter. However, ingestion rates seemed highly sensitive to both season and acclimation time. Within each season, there was a consistent trend of increasing ingestion rate during the third week of the experiment, and this was most discernible in the stimulant treatment.