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.

本研究于2006年11月启动，2008年11月结束，旨在调查托雷斯海峡中部马西格岛（Masig Island）与马斯登岛（Marsden Island）周边海域海洋无脊椎动物（marine invertebrates）的附着招募动态。研究采用表面带有均匀凹坑的陶土附着基（settlement plates，规格为11 cm × 11 cm），在两座岛屿北侧各设置3个采样点位，点位间距为200米；每个点位再划分为3个亚站点，亚站点间间距为20米。每个亚站点分别在6米与12米水深处布设5块附着基，块体间距约1米。附着基通过不锈钢底板固定于礁体之上，底板与礁体间距约1厘米，可确保各类生物在附着基两侧均可完成附着与招募过程。附着基分别于每年夏季伊始的11月，以及冬季伊始的5月完成布设。每个季度结束时，研究人员会对每块附着基进行原位拍摄：附着基一角的两侧均带有小型编号标签，用于样本标识。拍摄完成后将附着基取回，并更换新的附着基。在研究的第一年，每个季度布设的附着基还会在放置4个月后进行原位拍摄，以获取单季度内底栖生物（benthic organisms）招募动态的相关数据。生物的丰度与盖度通过PC屏幕上以Microsoft Windows XP 图片和传真查看器（Microsoft Windows XP Picture and Fax ViewerTM）展示的附着基图像进行评估。本研究旨在探究托雷斯海峡中部固着型海洋无脊椎动物在不同季节与年份间的附着招募情况，其中野生商用沐浴海绵物种Coscinoderma matthewsi的附着招募为研究的核心关注方向。