When you dive most of the time for science, you start to forget what a dive feels like where you don’t have tasks to do, where you don’t need to swim into the current in order to survey, and where you don’t have an unimaginable amount of equipment strapped to your BCD. The truth is, I wouldn’t swap it for the world.
When we are researching in the Maldives, our daily dives begin early as we take advantage of every ounce of daylight... whether it’s raining or sunny, windy and choppy or calm and placid, soaring current or gentle flow- we are gearing up to dive. Our buddy checks go beyond the usual ‘BCD, weights, releases, air and final check’ to encompass ‘do you have the tape measure?’ and ‘will you roll the transect line out whilst I photograph?’, and, my personal favourite ‘we’ll have to swim into the current to survey - is that ok with you?’
Buddy check complete, we descend into the blue ocean, and as the reef comes into view, we all take our action posts. We each have a set number of tasks to complete. What makes this challenging is that we are limited by both time and air.
Our first and most important task is to locate our permanent monitoring station. A permanent monitoring station may sound impressive, but in reality it is very basic. Each transect is marked by several small pieces of steel rebar that extend from the bottom only 30-50 cm, hidden between coral heads on a reef with very few distinctive landmarks. If that isn’t challenging enough, these rebars are rapidly colonized by algae, sponges and ascidians and become part of the reef. Provided that our trusty GPS coordinates get us to the monitoring station with ease, we can begin our data collection.
At each station we photograph a section of reef between the rebars, re-photographing the exact same area each time we revisit a site- this helps us to build a long-term photographic database of the reef and how it changes over time. Around each station, we characterize the reef fish community using 30m X 4 m belt transects. We count the number of fish that cross the transect line, estimate their size, and record what species they are. Using 10 m long lead lines we conduct benthic surveys, recording the substrate and animal or plant that has colonized the reef at 10cm intervals. We will quantify both fish and benthic cover at three different depths; deep, mid and shallow, as these assemblages often change with depth and we want to have a full picture of the reef.
As our computers begin to buzz indicating the dive has come to an end, our team re-groups at 5m for a safety stop. Ascending to the surface together, we haul our gear on to the boat, thirstily guzzle some water and get the next diving tank ready to go.