Recruitment of sponges and other sessile organisms in central Torres Strait, Australia (MTSRF Project 1.3.2)

A study of recruitment of marine invertebrates around Masig Island and Marsden Island, in central Torres Strait commenced in November 2006 and ended in November 2008.Terracotta settlement plates (11 cm x 11 cm) with well pitted surfaces were deployed at three locations on the northern side of each island, with locations two hundred metres apart. Each location was further divided into three sites, each twenty metres apart. At each site, five plates were deployed, roughly one metre apart, at both six metres and twelve metres depth. The settlement plates were attached to a stainless steel base plate anchored to the reef and rested approximately one centimetre above the reef allowing for settlement and recruitment of organisms on both sides of each plate.The plates were deployed in November, at the start of summer, and in May, at the start of winter. At the end of each season, the top and underside of each plate, which was identified using a small numbered-tag on both sides on one corner, was photographed in situ, removed and a new plate deployed. During the first year plates were also photographed in situ after four months in each season to provide information about the recruitment of benthic organisms within a season.Abundance and percent cover of organisms was assessed from images of tiles displayed by Microsoft Windows XP Picture and Fax ViewerTM on a PC screen. This research was undertaken to assess the recruitment of sessile marine invertebrates in central Torres Strait across seasons and years. Recruitment of the wild commercial bath sponge species, Coscinoderma matthewsi, was of specific interest.

本研究针对托雷斯海峡中部马西格岛（Masig Island）与马斯登岛（Marsden Island）周边海域的海洋无脊椎动物补充招募过程展开，研究周期为2006年11月至2008年11月。表面带有细密凹坑的陶土定居附着板（规格11 cm × 11 cm）被布设至两座岛屿北侧的3个采样点位，点位间距为200米。每个采样点位进一步划分为3个亚位点，亚位点间间距为20米。每个亚位点分别在6米与12米水深处布设5块陶土板，板体间距约1米。定居附着陶土板被固定于锚定在珊瑚礁上的不锈钢基座上，与礁体保持约1厘米间距，以便各类生物在板体两侧均可完成附着与招募过程。研究分别于夏季伊始的11月与冬季伊始的5月布设陶土板。每个季节结束后，研究人员将对每块板体进行原位拍摄——板体的一个边角两侧均带有小型编号标签以区分正反面，拍摄完成后将板体回收并更换新的陶土板。在研究的第一年中，还会在每个季节布设4个月后对陶土板进行原位拍摄，以获取单季内底栖生物招募动态的相关数据。通过在PC屏幕上使用微软Windows XP图片和传真查看器（Microsoft Windows XP Picture and Fax ViewerTM）展示的板体图像，评估生物的丰度与盖度百分比。本研究旨在评估托雷斯海峡中部海域固着型海洋无脊椎动物在不同季节与年份间的招募情况，其中野生商用沐浴海绵物种马修斯腔海绵（Coscinoderma matthewsi）的招募过程为重点关注对象。