Continuing research support for the Kailag sponge farm in the Torres Strait: aspects of sponge ecology and life history
Project Leader: Dr Chris Battershill, AIMS
Following on from decades of research through a number of agencies, including the MTSRF, a commercial sponge farm was established in early 2009 at Masig Island, growing Coscinoderma sponges for harvest. Further studies of the natural distribution and abundance patterns of the farmed sponge C.matthewsi in the vicinity of Masig Island suggest that previously recommended seed stock guidelines would support the harvest of at least 700 donor sponges per year. This would mean that Kailag’s current farming operation could be sustained by the existing sponge population. Investigations of the reproductive and larval ecology of C. matthewsi revealed that the species is viviparous, releasing tufted parenchymella larvae during daylight hours over an extended period in the summer (December 2009). Larvae swam at the surface for 18-24 h, and settlement to the substrate was enhanced on established biofilms, with 80% of larvae settled after 42 h. Coupled with Torres Strait’s strong current profiles, these behavioural observations suggest that this species is capable of broad-scale distribution through larval dispersal. Genetic analyses support a high degree of connectivity between C. matthewsi populations from central and eastern Torres Strait reefs, indicating that any farming-related translocation between these areas would be low-risk for wild populations. While post-settlement mortality and growth rates are yet to be investigated, artificial larval production and selective settlement onto farming structures could potentially be a more efficient way to stock the sponge farm than the present method of harvesting wild sponges. The Torres Strait Regional Authority provided additional funding to conduct a series of experiments into the effects of a range of collection and handling methods on C. matthewsi explants, with the aim of optimizing explant survival and growth and streamlining sponge farm operations.
Continuing research support for the Kailag sponge farm in the Torres Strait: interactions with hawksbill turtles
Project Leader: Dr Mark Hamann, JCU
Surveys were conducted in August 2009 in response to concerns about possible interactions between foraging hawksbill turtles and the Kailag sponge farm on Masig Island. Relatively small numbers of hawksbills were observed on the reefs around the Island, and while stomach samples revealed that the turtles were feeding on siliceous sponges, no evidence was found suggesting the turtles ate the non-siliceous Coscinoderma spp. It was concluded that it is unlikely that there will be any significant interaction between hawksbills and the sponge farm, although repeated future surveys are recommended to detect any increases in turtle numbers or potential diet-switching behaviour to more easily available sponge species.
Final Report on Project Activities, June 2010. Project 1.3.2 extends on work carried out through the CRC Torres Strait to establish farming protocols and best practice guidelines for growing the commercial bath sponge Coscinoderma matthewsi at Masig Island in Torres Strait. During the course of the MTSRF-funded research, researchers (a) studied the ecology and demography of sponges in Torres Strait, especially C. matthewsi, as a possible surrogate for ecosystem connectivity and health of benthic communities in Torres Strait; and (b) established a firmer knowledge base to underpin the sustainable environmental management of Torres Strait sponge framing. This document reports on outputs to date, including (a) the known distribution and abundance of sponges in Torres Strait at a range of spatial scales; (b) a demonstrated low incidence of disease in wild sponge populations; and (c) temporal trends in sponge demographics plus evidence of the success of existing farming and harvesting procotols.
Annual Report for Year 3 of MTSRF Project 1.3.2 (2008/2009) prepared by researches of the Australian Institute of Marine Science.
Annual Report for Year 2 of MTSRF Project 1.3.2 (2007/2008) prepared by researchers of the Australian Institute of Marine Science.
MTSRF Project 1.3.2 Annual Report for 2006/2007 prepared by researchers of the Australian Institute of Marine Science. Sponges are a dominant organism on coral reefs throughout Torres Strait and have been shown to play an important ecological role by acting as a nursery or recruitment habitat for other species of economic importance. In addition to their ecological importance, sponges that have good quality spongin fibres have commercial value and may be sold as bath sponges. This report examines the size of the Coscinoderma sp. population in Torres Strait; determines the possible risks of translocating individuals of Coscinoderma sp. within Torres Strait in the interests of setting up bath sponge farms where it is not naturally abundance; and highlights when, where and how often sponges such as Coscinoderma recruit onto coral reefs in Torres Strait.
A project report on the distribution and abundance of the bath sponge Coscinoderma in Central and Eastern Torres Strait.