A crown-of-thorns starfish (Acanthaster planci) control program at Grub Reef, central Great Barrier Reef

A crown-of-thorns starfish control program was conducted on Grub Reef, a mid-shelf, lagoonal reef in the central Great Barrier Reef. The control site was located on the leeward, north-western side of the reef, in an area which previous surveys indicated had large numbers of starfish. The site covered an area of 0.64 km² and contained 53 patch reefs interspersed amongst a predominantly sandy substrate of 10-30 m depth. Each patch reef was mapped, marked and numbered for identification during the control exercise. Starfish control was carried out by 15 Royal Australian Navy divers between 3 and 17 July 1986. Each patch reef was searched by a squad of 5 divers, spaced about 5 m apart searching to a depth of 20 m. All starfish observed were injected with 5-10 ml of saturated copper sulphate solution using "Dupont" agricultural injection guns. Once injected, starfish were marked with a cut from a knife to avoid repeated injection. The final 2 days of the control exercise were used to inject starfish on adjacent patch reefs to the north and west of the control site. As a guide to the efficiency of the control exercise, starfish were injected on patch reef No.3 over the last 4 consecutive days of the control.Biological surveys were conducted 2 weeks prior to the start of the program (23-26 June 1986), and 1 month and 6 months after the program had ended (20-23 August 1986 and 20-22 January 1987). Three different methods were used during each of these surveys: (1) The perimeter of Grub Reef, including a group of patch reefs to the west of the main section of the reef, was surveyed using the manta tow technique. Counts of starfish and estimates of coral cover were recorded; (2) Twenty-six of the patch reefs were initially chosen randomly and then searched intensively by SCUBA divers during each of the 3 surveys. Two divers swam around the sides, and across the top of each patch reef, recording the number of starfish observed and estimating the relative cover of live and dead corals using the same categories as manta tow; (3) A 50 m line transect was laid along the crest of each of the 26 patch reefs, to estimate the relative cover of live and dead corals.A detailed record was kept of the cost of undertaking all various aspects of the control program. The total cost of the program was calculated by including the direct outlay recorded plus calculating shadow prices for the services provided by the Government.
This study was undertaken to evaluate the effectiveness of a crown-of-thorns starfish (Acanthaster planci) control program at Grub Reef in the central Great Barrier Reef and to assess the biological benefits gained in the light of the costs of the program.

棘冠海星控制项目在大堡礁中部的中陆架潟湖礁Grub Reef开展。控制区域位于该礁的背风西北侧，此前调查显示该区域海星数量较多。该区域面积为0.64 km²，包含53个斑块礁，散布在10-30米深的以沙质为主要基底的海域中。每个斑块礁均被绘制地图、标记并编号，以便在控制作业中识别。
1986年7月3日至17日，15名澳大利亚皇家海军潜水员实施了海星控制作业。每个斑块礁由5名潜水员组成的小队进行搜索，队员间距约5米，搜索深度达20米。所有观测到的海星均使用“杜邦”农用注射枪注射5-10毫升饱和硫酸铜溶液。注射后，用刀在海星身上划一道痕迹，避免重复注射。控制作业的最后两天用于对控制区域北部和西部相邻的斑块礁进行海星注射。为评估控制作业的效率，在作业的最后4天连续对3号斑块礁的海星进行注射。
生物调查分别在项目启动前2周（1986年6月23-26日）、项目结束后1个月（1986年8月20-23日）及6个月（1987年1月20-22日）开展。每次调查采用三种方法：（1）采用蝠鲼拖曳法调查Grub Reef周边区域（包括主礁西侧的一组斑块礁），记录海星数量并估算珊瑚覆盖率；（2）首次随机选取26个斑块礁，在三次调查中均由水肺潜水员进行密集搜索。两名潜水员沿每个斑块礁的侧面游动并穿越顶部，记录观测到的海星数量，并采用与蝠鲼拖曳法相同的分类标准估算活珊瑚与死珊瑚的相对覆盖率；（3）在26个斑块礁的每个礁顶铺设一条50米长的线样带，以估算活珊瑚与死珊瑚的相对覆盖率。
项目各方面的成本均有详细记录。项目总成本计算包括已记录的直接支出，以及政府提供服务的影子价格核算。
本研究旨在评估大堡礁中部Grub Reef棘冠海星（Acanthaster planci）控制项目的有效性，并结合项目成本评估所获得的生物学效益。