The reefs in southern Mozambique are under increasing pressure from tourism development and growing numbers of artisanal and sport fishers. There are still pristine areas of reef but other areas are clearly beginning to be impacted. Operation Wallacea is running a series of annual surveys that will help identify the relative importance of each of the reef systems for biodiversity conservation and also provide data to quantify changes over time. In order to avoid data quality problems between years the data are being collected in a way that is independent of the skill of the surveyor, to avoid variation in the skills of individual surveyors between years masking any underlying trends. Reef fish communities are being recorded from replicate transects on each reef system using a twin video system developed by the University of Western Australia and software which combines the images and enables species identifications and fork lengths to be measured precisely. Coral cover and community structure of hard and soft corals are being assessed using a digital camera photographing replicate randomly positioned 0.25m X 0.25m quadrats on each reef. Volunteers on this project will be diving to help collect these data but will also be spending considerable amounts of time helping with the data analysis in the on-site laboratory. The 2010 programme will repeat the 2009 surveys of all the main reefs in the Ponta do Ouro area to identify changes over this period as well as examining the effects of depth on the various communities. This work forms part of the much larger Great East African Marine Transect project, which aims to complete similar sampling on reef systems from Sodwana Bay in South Africa to Mombassa in Kenya. In weeks 7 - 8 and 9 - 10, a small mobile survey team will be completing video and photographic surveys and analysis on additional reefs along this transect. Volunteers joining this project at any time though will have the chance to experience some of the most exciting diving available worldwide with regular sightings of giant manta rays, sharks, whales and dolphins as well as gaining some excellent field skills in reef species data analysis.