Bath sponge aquaculture in Torres Strait, Australia: Effect of explant size, farming method and the environment on culture success

Global demand for bath sponges far exceeds supply and cannot be met by harvesting natural populations. Aquaculture is considered the only method that could supply sufficient and sustainable quantities of bath sponges and it may also be a suitable industry for remote coastal communities such as in Torres Strait, Australia. A series of farming experiments were done in Torres Strait using the common bath sponge Coscinoderma sp. to establish commercially viable culture procedures. The first experiment compared several farming methods and found that mesh panels promoted greatest sponge growth and survival, probably because they cause minimal tissue damage. Using mesh panels, a subsequent experiment examined the importance of farming site and season of transplant. Sponge growth and survival were similar between the three farming sites, while growth was highest for explants transplanted at the end of winter. These explants doubled in size on average in 6 months. The final experiment examined the optimal explant size to transplant and found that “medium sized” explants (∼ 100 cm3) have good growth and survival, and permit high explant production from a given amount of sponge biomass. This study has identified good farming procedures, and coupled with the high growth rates of Coscinoderma sp., it suggests that bath sponge aquaculture in Torres Strait will be a viable industry.