Crown of Thorns Starfish (COTS) Control Program [Map and animation]
Acanthaster planci, When Crown-of-thorns seastars are in high densities they can form a feeding front, aggregations that progress up the reef slope, eating the live coral they encounter.
by AIMS - LTMPThis map shows the number of large (> 40 cm) Crown of Thorns Starfish (COTS) removed by the AMPTO run control program (culling of COTS) during their first visit to each of the control sites. This map shows the first visit to each site as this is the visit when typically the most COTS are detected. In subsequent visits the number of COTS is typically reduced as a result of the culls from previous visits.
Each of the small black areas on the map represent an area where the control program operates. If there is a coloured dot over the polygon then the control vessel has performed one or more control dives. If there is no dot then this means that it is a planned control site that has not yet been visited.
As of May 2015 the control program is implemented with two vessels that operated almost continually, performing a control voyage every two weeks. When they visit the areas they typically have up to 10 divers slowly move over the control area searching for COTS and killing them with a single bile salt injection. Divers will typically perform this search for over an hour and if an area has lots of COTS then they will perform multiple control dives over several days to "fish down" the number of COTS.
The animation below shows the sites the control sites over the last 2 years, with the associated Cost Per Unit Effort (CPUE) of removing COTS at each site. The CPUE is the a measure of how much time is needed to remove each COTS at the site. Its units are COTS culled per minute of dive time. If a reef has a low CPUE then it typically indicated that it is very difficult to find COTS to cull, then thus probably indicates that there is a low number of COTS on the reef.
You can pause the animation or go to a particular year using the video controls in your web browser. Some browsers only show these controls when you click or hover your mouse over the video. You can download this animation for use in presentations in Animated GIF format and MP4 video format
You can view and investigate the data is more detail using the interactive map of this dataset.