Transportation methods for restocking of juvenile sea cucumber, Holothuria scabra.

Abstract

The sandfish, Holothuria scabra, is a heavily exploited sea cucumber species. Minimising stress in the transportation of hatchery-produced sandfish juveniles to release sites is critical for successful restocking. Replicate groups (n=4) of 20 hatchery-produced juveniles (1–5 g) were held in plastic bags with oxygen under 6 transport durations (0, 2, 4, 8, 12 and 24 h), two media (water or saturated sponge), and two temperature regimes (ambient and cool). Subsequent deaths and sand burrowing of the groups in release chambers were monitored for 5 days. Juveniles eviscerated or died only in treatments at ambient temperature on sponge for 24 h. Oxygen consumption in bags was reduced at cool temperature. On the first day after release, the normal sand burrowing was suppressed in juveniles held for 12 and 24 h, suggesting that pre-release acclimation for 1 day at field sites would benefit restocking. After the initial 'shock' of transport, handling stress appeared to increase burrowing behaviour for several days. Hatchery-produced sandfish also proved hardy for transport in high densities (100 and 200 juveniles per bag) and transportation stress will be minimised in seawater held at cool, constant temperature.