Effect of farming method, explant size and environment on the success of bath sponge aquaculture in Torres Strait (CRC-TS Project: Task Number T1.6a)

Sponges were experimentally farmed at three sites in the Yorke Islands: Kodall Island North, Masig Island East and Masig Island North. Sites were located on the leeward side of the islands. At each site, Coscinoderma matthewsi explants were farmed at a depth of 12 m, using riser lines, approximately 3 m apart. For each farming experiment, 10-50 sponges were partially harvested, whereby one third of each sponge was left behind to regrow. The collected sponge tissue was cut into explants, each with at least one side still covered in pinacoderm. At no time were sponges or explants exposed to air. For each experiment, 15-20 explants were measured at the start of the experiment to determine initial explant size and all surviving explants were measured at the end of each experiment. The length, width and height of each explant were measured with a ruler to the nearest centimeter and the volume calculated. Because of slight differences in initial size between some explants, percent growth was calculated.Explants of Coscinoderma matthewsi were experimentally farmed for nine months using three methods, threaded line, mesh and mesh-line, with each method testing two material types. Coscinoderma matthewsi was experimentally farmed at Kodall North and Masig North, with three riser lines per treatment at each site. Each riser line had 6 explants, thus 36 explants were cultured per treatment. In total, 216 explants were experimentally farmed with a mean initial size of 113 ± 9 cm³.Coscinoderma matthewsi was experimentally farmed at Kodall North, Masig East and Masig North, with explants transplanted at the end of summer (March 2005) and at the end of winter (September 2005). Explants would therefore experience either falling or rising water temperatures, respectively, for the first 6 months of culture. Two riser lines were deployed per farming site/seasonal transplant, with one mesh panel holding 6 explants attached to each riser line at 6 and 12 m. Due to inadequate flotation, the riser lines were not vertical in the water column through out the entire tidal cycle, and thus we could not accurately determine the effect of depth. Twenty-four explants were farmed per site/seasonal transplant, with 144 explants experimentally farmed in total. The mean initial size of explants between sites/seasons ranged from 166 ± 15 to 255 ± 18 cm³. This experiment ran from March 2005 to September 2006.A temperature recorder (HOBO® Water Temp Pro), deployed at 12 m at the Masig North site, recorded water temperature during the length of the project. A water flow meter (General Oceanics INC) was also deployed for 24 hr periods for three times at each site.At Kodall North, explants of three initial sizes were experimentally farmed: small, 39 ± 5 cm³; medium, 104 ± 8 cm³; and large, 313 ± 27 cm³. Explants were farmed inside mesh panels, attached to riser lines. Three riser lines were used, each holding 5 explants of each size treatment. In total, 45 explants were cultured. This experiment started in June 2005 and ran for 6 months.A temperature recorder (HOBO® Water Temp Pro), deployed at 12 m at the Masig North site, recorded water temperature during the length of the project. A water flow meter (General Oceanics INC) was also deployed for 24 hr periods for three times at each site. This research was undertaken to develop aquaculture methods for optimal and environmentally sustainable commercial production of bath sponges in at least one location selected for the project. Another aim of this project was to promote the transfer of skills and technology from this project directly into the local community, by involving York Islanders in diving and monitoring the farming experiments.本研究于约克群岛（Yorke Islands）的3个实验站位开展海洋海绵人工养殖实验，分别为科多尔岛北部（Kodall Island North）、马西格岛东部（Masig Island East）及马西格岛北部（Masig Island North），所有站位均设置于岛屿背风侧。 在每个站位，研究人员采用立管绳（riser lines）以约3米的间距，在12米水深处养殖马修斯腔星海绵（Coscinoderma matthewsi）外植体（explant）。每次养殖实验中，选取10~50个海绵个体进行部分采收，保留每个海绵的1/3组织以实现再生。将采集的海绵组织切割为外植体，每个外植体至少保留一面被皮层（pinacoderm）覆盖。实验全程未使海绵个体或外植体暴露于空气中。 每次实验初始阶段，选取15~20个外植体测量以确定其初始尺寸；实验结束时，测量所有存活外植体的尺寸。采用直尺测量每个外植体的长、宽、高，精度至厘米，并计算其体积。由于部分外植体初始尺寸存在细微差异，因此通过生长百分率评估其生长情况。 本研究采用3种养殖方式对马修斯腔星海绵外植体开展了为期9个月的养殖实验，分别为单绳缠绕法、网片法及绳网复合法，每种方式均测试2种材料类型。实验分别在科多尔岛北部与马西格岛北部站位开展，每个站位的每个处理组设置3根立管绳，每根立管绳挂载6个外植体，即每个处理组共培养36个外植体。本次实验总计养殖外植体216个，初始平均体积为113±9 cm³。 实验同时在科多尔岛北部、马西格岛东部及马西格岛北部站位开展，分别于2005年夏末（3月）与冬末（9月）进行外植体移植，使外植体在养殖前6个月分别经历水温下降与水温上升的环境变化。每个养殖站位/季节性移植组设置2根立管绳，每根立管绳于6米与12米水深处各挂载1块搭载6个外植体的网片。由于浮力不足，立管绳在整个潮汐周期内无法保持垂直于水体柱，因此无法准确评估水深对养殖效果的影响。每个站位/季节性移植组养殖24个外植体，本次实验总计养殖外植体144个，初始平均体积范围为166±15 ~255±18 cm³。实验周期为2005年3月至2006年9月。 在马西格岛北部站位12米水深处部署HOBO®水温记录仪（HOBO® Water Temp Pro），全程记录项目实施期间的水体温度。同时在每个站位使用通用海洋学公司（General Oceanics INC）生产的水流计进行3次、每次24小时的流速测量。 在科多尔岛北部站位，开展了3种初始尺寸梯度的外植体养殖实验：小型组（39±5 cm³）、中型组（104±8 cm³）及大型组（313±27 cm³）。外植体挂载于网片内，并固定于立管绳上。实验设置3根立管绳，每根立管绳分别挂载5个不同初始尺寸的外植体，总计培养外植体45个。本次实验于2005年6月启动，持续6个月。 在马西格岛北部站位12米水深处部署HOBO®水温记录仪（HOBO® Water Temp Pro），全程记录项目实施期间的水体温度。同时在每个站位使用通用海洋学公司（General Oceanics INC）生产的水流计进行3次、每次24小时的流速测量。 本研究的核心目标为开发最优且环境友好的商业养殖方法，以实现至少一个选定站位的沐浴海绵规模化可持续水产养殖。本项目的另一目标为通过邀请约克群岛居民参与潜水作业与养殖实验监测，将本次实验积累的技术与经验直接传授给当地社区。