Developing methods for commercially farming bath sponges in the Palm Island group, central Great Barrier Reef

In August 2005, experimental farming of the sponges Coscinoderma sp. and Rhopaloiedes odorabile commenced at three of the nine islands of the Palm Island group in the central Great Barrier Reef: Great Palm Island (1 site), Fantome Island (3 sites) and Pelorus Island (2 sites).Eleven farming techniques were tested. These were grouped into four general categories: threaded line, cut explant, spike and mesh panel methods. Within each category different materials such as nylon, polyethylene and polypropylene lines or different compartment sizes were trialled.Sponge explants were obtained by partially harvesting approximately 20 sponges of each species from the local populations, keeping the sponges underwater at all times. Both Coscinoderma sp. and Rhopaloiedes odorabile explants were deployed within 2 x 2 m plastic grids, suspended upright 3 m from the substrate at an average depth of 12 m. Three grids were used per sponge species, each holding 5 replicates of each treatment (farming technique). Survival and growth of the explants were monitored in situ every few months over a period of 2 years to determine if there were also seasonal differences.The importance of a nursery period for Coscinoderma sp. and Rhopaloiedes odorabile was examined by comparing growth and survival of explants threaded onto 4 mm nylon line, explants farmed in mesh panels and explants placed in mesh panels for 4 months then threaded onto nylon line. Explants were obtained by partially harvesting approximately 5 individuals of each species. For both species, 5 replicates of each treatment were used. The ropes or mesh strips were >= 1 m apart, in an upright position at a depth of approximately 12m. Each method replicate had 5 explants approximately 15 cm apart. The explants were farmed for a period of 9 months.
An experiment was carried out to test a range of farming techniques at different locations within the Palm Island group, to determine the most successful method and location for commercially farming Coscinoderma sp. and Rhopaloiedes odorabile. For both species, a second experiment was carried out to determine whether growth and survival using the threaded line technique, was higher in explants, which were first allowed a 'nursery period' during which explants were allowed to heal in mesh panels.

2005年8月，研究团队于大堡礁中部的棕榈岛群（Palm Island group）的9座岛屿中的3座，启动了海绵Coscinoderma sp.与Rhopaloiedes odorabile的实验养殖工作：布设点位包括大棕榈岛（Great Palm Island，1个站点）、范托姆岛（Fantome Island，3个站点）与佩洛鲁斯岛（Pelorus Island，2个站点）。本次实验共测试11种养殖技术，可划分为四大类别：穿线法（threaded line）、切块外植体法（cut explant）、插桩法（spike）与网板法（mesh panel）。每一类别下均测试了不同的养殖材料（如尼龙线、聚乙烯线、聚丙烯线）以及不同的隔舱尺寸。

海绵外植体（sponge explant）通过从当地种群中部分采收各物种约20个个体获得，全程保持海绵处于水下环境。两个物种的海绵外植体均被安置于2×2米的塑料网格中，以直立姿态悬挂于距底质3米处，平均水深12米。每个海绵物种使用3个网格，每个网格对应每种养殖技术处理的5个重复样本。在为期2年的监测周期内，研究人员每隔数月对这些外植体的存活与生长情况进行原位（in situ）监测，以探究是否存在季节差异。

为探究暂养期（nursery period）对两个物种的重要性，研究团队开展了对比实验：分别测试穿于4毫米尼龙线上的外植体、网板养殖的外植体，以及先在网板中放置4个月后再穿至尼龙线上的外植体的生长与存活情况。本次对比实验的外植体通过部分采收各物种约5个个体获得。每个物种的每种处理均设置5个重复样本。绳索或网板条间距≥1米，以直立姿态放置于约12米水深处。每种方法的每个重复样本中放置5个外植体，间距约15厘米。本次养殖周期为9个月。

第一项实验在棕榈岛群的不同点位开展，旨在测试多种养殖技术，以确定可用于Coscinoderma sp.与Rhopaloiedes odorabile商业化养殖的最优方法与布设点位。针对两个物种，本研究还开展了第二项实验，以探究先经过网板暂养期（即外植体在网板中完成愈合）的外植体，采用穿线法养殖时的生长与存活情况是否更优。