All monitoring dives are conducted using Megalodon Closed circuit rebreathers (CCR) to don’t disturb the fish, increased bottom time and safety. We return to the monitoring sites using a GPS coordinates and in water recognition of the site. There is no return to the exact transect although the transects are done within the same site.

Fish Census- four transects of 25 m’ each are conducted at every site. Every transect is recorded on video and all fish counts are outspokenly by the diver. The data recorded are specie, number of individual, size and distance from the transect line. The diver follow the transect line twice first counting the swimming fish and on the way back all the benthic species and for better videography video light is add.

Invertebrate and alga coverage- Every 2 m’ photo-quadrates of 25cm by 25 cm is taken on the same line transects that is used for the fish census. The photos are made with Canon G1X with 2 external flash Ikelite DS51. All photos are uploaded to the coralenet web site for analyze. We use annotation point generation of Stratified random, 4 rows x 4 columns of cells, 1 points per cell (total of 16 points). the photos are analyzed with assistance from machine learning program when confidence level is higher than 90% automatic annotation is made, for lower confidence level manual entry is made. The source is open to the public (https://coralnet.ucsd.edu/source/307/).

Time per effort Invertebrates-  this is a complementary method to the photo-quadrates since it does not represent all the species that exist. At this method, the diver swim freely for 10 minutes and write down every species that is seen without stating the amount of coverage or number of individuals. Species that are not recognized are collected for later analysis