Using High Resolution Video Mosaics to Assess the Impacts of

 

Coral Bleaching

 

 

Video mosaics are ideal for studying the impact of bleaching events over large areas due to their ability to provide a detailed photographic record of hundreds of coral colonies without extensive tagging.

 

 

 

 

The 3 mosaic images (above) were acquired in December 2005, October 2006 and October 2007 at an inshore patch reef site at Andros Island, Bahamas. The initial 2005 image was used to document coral colonies affected by the mass bleaching event of 2005 that peaked earlier that year (September/October 2005). Using the 2005 image as a standard, the other two were warped to overlay on top of it using standard GIS software. The affected colonies were then followed through time to assess their subsequent health (Below). Note that the images above are drastically reduced for this web page. A high resolution version of the 2007 mosaic is available (14 Megabytes).

 

 

 

 

The above images highlight the advantages of using video mosaic technology for monitoring bleached colonies. In this example we see that the degree of bleaching in December 2005 was not an accurate predictor of mortality over the two year period. Instead we found that the bleached finger coral (Porites porites) was able to recover almost completely in the two year survey period while the pale star coral (Montastrea faveolata) suffered signficant partial mortality (B).