Effect of divers on reefs in Sharm-el-Shei Egypt

In this blog I will be discussing the results of a study conducted by Julie P. Hawkins and Callum M. Roberts of the British Ecological Society.  I found the study in a peer reviewed journal called The Journal of Applied Ecology, the study is called Effects of Recreational Scuba Diving on Coral Reefs: Trampling on Reef-Flat Communities.  The study looked at the effects of scuba diving on a reef off the coast of Sharm-el-Shei in Egypt.  The reef is a popular dive spot that sees hundreds of divers each week.  The study compared the health and marine life in the area of this reef with another similar reef that is more difficult to access and therefore much less dived.  The findings are quite shocking!

The study was conducted by randomly choosing 20 sections of the reef and comparing them with 20 sections from the healthy or unvisited reef nearby.  A complete evaluation of the sections was then done, recording each hard and soft coral, broken or fragmented coral and  measuring the size, species, amount and health of all the coral on the reef.  The same was done for the control or unvisited reef. 

Data was then analysed using ANOVA which is a method for analyzing reef quality.   Percentage cover and species composition data are analysed using a cluster analysis and the Bray-Curtis similarity index for cover data, which is a way to analyse clustered and ununiformed data. 

So what were the findings?

Broken and dead coral was much more prevalent on the dived reef.  The percentage cover of hard coral was significantly reduced on the dived reefs, as was the areas of bare substrate, which is where nothing is growing.  The amount of soft coral, as well as the height and diameter were also greatly reduced on the dived reef. 

Although there was a large difference between the coral size and life of the differing reefs, the study found that divers didn’t completely kill any of the living coral communities.  The constant breaks and cuts incurred on the corral from the divers will force the coral to spend energy repairing itself rather than growing.  This makes for shorter, stockier coral and less coral abundance overall but it does not kill the reef completely.  Although the study finds that divers are not threatening to completely kill the reef, they do cause a lot of damage.  The undived reef also had more fish and marine life around it, which may be a sign that divers are scaring the fish away from their natural habitats to go somewhere where they won’t harassed by divers.

Although its bad news, it is interesting to actually get some hard evidence on the effect that divers are having on our reefs!  I hope you enjoyed this blog entry!  Stay tuned next week for my next blog posting!

Below I have attatched the link for the study, and a picture of a beautiful and healthy reef in Sharm-el-Shei!

Makes me want to go diving in Egypt!

http://www.jstor.org.ezproxy.tru.ca/stable/pdfplus/2404267.pdf?acceptTC=true