Overview of the sharkwatch programme 2009 – 2013

Abstract

Sharkwatch was launched in 2009 to collect baseline information on abundance of reef associated sharks in Maldivian waters, so as to assess the status of stocks and monitor the effectiveness of the fishing ban implemented the same year. Since its inception, a number of resorts/dive centres have participated in the programme and continue to send monitoring data on a monthly basis. The survey uses the Roving Diver Technique which is a rapid and effective assessment technique that can be used by volunteers to collect fish data. The survey form includes 8 species of sharks which are most likely to be encountered, while other species are recorded as “Others” and identified if possible. Over the 4 years, a total of 11,704 surveys were undertaken at 540 sites, with a total of 8,255 hours spent surveying. A total of 23,798 sharks were recorded on these surveys. The geographic spread of the survey area is quite wide-spread from the north to south of Maldives, though a greater number of surveys were done in the central atolls. The number of surveys conducted and time spent surveying increased over the four year survey period, with the number of surveys during the 4th year being almost thrice that during the 1st year. This indicates that participants realised the importance of Sharkwatch and wanted to contribute to the programme. The majority of sites surveyed showed the presence of sharks, while 24% of the sites did not have any sharks. However, the numbers of sharks observed at the sites were low, with 1 to 10 sharks being observed at about 50% of sites. The average number of sharks per survey varied amongst the atolls. Baa Atoll, which used to be one of the atolls where shark fishing was carried out prior to the ban has one of the lowest averages. This suggests that shark fishing at Baa Atoll may have caused a population decline. The most commonly seen species was the Whitetip Reef Shark (Triaenodon obesus), which was followed by Grey Reef Shark (Carcharhinus amblyrhynchos) and Blacktip Reef Shark (Carcharhinus melanopterus). An increase in number of sharks seen per survey was seen for Whitetip Reef Shark and Grey Reef Shark at some of the key sites. While these were not 5 | O v e r v i e w o f S h a r k w a t c h P r o g r a m m e ( 2 0 0 9 – 2 0 1 3 )

significant increases and was not a common occurrence it is encouraging to see that the average number of sightings has not declined over time. The average number of sharks seen per survey at the 10 most surveyed sites was seen to vary greatly from one site to another, with Site 4 having the highest average, which also showed an increase in average sightings over the four year period. These are encouraging results as they are indicative of possible increase in shark abundance at these sites. The average number of sharks seen at the 10 sites with the highest shark abundance, showed that the highest abundance was seen at a site which was surveyed 1/3 the number of times of the most surveyed site. This is another indication of good shark abundance at the site. Results of this overview are from a four year survey period and do not show clear cut increases in shark abundance. However, given the ‘slow’ life history of sharks, it is not surprising that significant population increases have not occurred within this time frame. It is encouraging to see that some results are indicative of an increase, and this fact emphasises the importance of long term continued and consistent monitoring of the selected survey sites. We hope these results are an incentive for more resorts/dive centres to participate in this programme. We also hope these results are useful to the Ministry of Tourism and other relevant authorities, whose cooperation is critical for the successful implementation of Sharkwatch.