Stereo Video Surveys
What is a Stereo Video System?
A Stereo-video system is a method used to collect accurate and efficient data for quantifying the abundance, diversity, size and biomass of reef fish and other underwater organisms.
By recording with two cameras simultaneously, SVS allows post-dive analysis of a defined transect boundary. Accurate measurements of distance from camera can also be made.
I voyaged to the Caribbean to collect my undergraduate dissertation data in collaboration with Operation Wallacea. I spent two months in Honduras on the island of Utila, the smallest of the Bay Islands. Utila is situated at the Southern end of the Mesoamerican Barrier Reef System supporting a diverse fish community.
My supervisor Dr Dominic-Adradi Brown, University of Oxford, an expert in Mesophotic Reefs offered me the chance to work on a new project that focused on the effects of two different dive techniques to study underwater fish populations. Scuba diving can be considered an invasive activity which can influence fish behaviour, thus affecting their distribution and abundance (Schmidt & Gassner, 2006). The potential problem of interface between sampling method and species behaviour has long been problematic. By using a Stereo video System (SVS) to collect fish biomass, abundance and minimum approach distance, we were able to determine the effects of dive gear choice on fish behaviour across a depth gradient. We compared conventional Open Circuit (OC) SCUBA, which traditionally produces lots of noise, with new advances in silent dive technology, known as a Closed Circuit Rebreather (CCR).
Results of this study were published in the Journal of The Marine Biological Association, U.K. Click here to find out more!
I later returned to Utila for two more summers in order to gain my PADI Divemaster qualification as well as lead the SVS team for OpWall. This consisted of supervising and training a group of undergraduate dissertation students on the efficiency of underwater SVS and Underwater Visual Census (UVC) fish surveys and benthic surveys, including analytical proficiency. Data collection added to an ongoing temporal data set.
This time I had the chance to venture to Tela bay, located on the north coast of Honduras. Here I witnessed one of the most unique and mesmerising reefs in the region. Coral cover is over 70%, which is up to 4 times more than other reefs located in the Mesoamerican Barrier Reef System. Check out Tela Marine Research Centre to find out more about their incredible underwater ecosystems and their ongoing work.
It is safe to say that the Caribbean reefs around Utila and Tela stole a piece of my heart!