Last Sunday, for the third year in a row, I took part in the Hong Kong Reef Check as a dive volunteer. The event I joined took place at Port Island (赤洲) and was organised by Blue Ocean Club, a local dive group (that’s some of them in the picture).
What is the Reef Check?
Reef Check is a global programme to promote the conservation of tropical and temperate reef sites worldwide with participants in over 80 countries. In Hong Kong, the Reef Check began in 1997 with just five teams of volunteer divers. It has over the years become an enormously popular activity — 63 groups of divers participated in 2014. It is coordinated by the Agriculture, Fisheries and Conservation Department (AFCD) and, according to its website, has two main aims:
- To raise public awareness about the value of coral reefs, the threats to their health and the solutions to these problems
- To obtain data on coral reef status in order to allow them to be managed on local and regional scales.
The reef check involves over 30 sites in Hong Kong and the data collected is published every year. There’s even a mobile app. The data serves as an important indicator of the health of key reef sites in Hong Kong over time, allowing for species diversity and potential threats to be monitored.
What do dive volunteers do?
the reef checking itself is a simple survey activity that non-specialists can easily carry out. A 100-metre transect is laid out at the site and divers swim along it recording marine organisms spotted within a 2.5 metre-wide band on either side of the line (this is known as a belt transect). Three kinds of data are recorded: fish, invertebrate and coral species. Divers don’t need to record anything and everything they spot; instead they focus on a set of ‘indicator species’ — a handful of species which are representative of the health and diversity of the reef. Furthermore, buddy teams are assigned just one of the three data categories to focus on. Rare species, coral damage and any other unusual sights are also recorded.
Volunteers receive a full briefing before the dive by a participating marine ecologist who accompanies the group. The divers are provided with a slate to record their observations and a species ID chart to help them as they conduct the survey.
Back to Sunday…
Blue Ocean Club’s reef check site is Port Island, aka Chek Chau 赤洲, in the north-east New Territories. It was a hot and sunny 30°C and conditions were great with supremely calm water. Visibility underwater was variable though: quite decent in the deeper part of the site but low and hazy in the ultra shallow area of the transect line. Not great for spotting those rare species listed on the slate in a such as the bumphead parrotfish (someone in AFCD was either having a moment of wild optimism or a bit of a laugh there).
My buddy and I were assigned the fish survey so we swam along slowly and managed to spot a lone butterflyfish, a sweetlips, and an awful lot of ‘other wrasse’. In general though, the shallowness of the transect area (read: snorkellable) meant there wasn’t a huge amount of fish in the area. We spotted the ubiquitous pearl-spots and some juvenile pufferfishes but these aren’t among the indicator species. As soon as we had reached the end of the line, we continued our dive a little deeper and saw a lot more fish: snappers, small grouper, and more types of butterflyfish — none of which we could record because they were not in the transect zone.
In any case, I was just happy I wasn’t landed with the invertebrate survey because the one thing there was no shortage of (neither there nor anywhere else in Hong Kong) was sea urchins! That lucky volunteer had a hell of a lot of counting to do …
Photo gallery: click to view
The Reef Check is a fun activity but as a scientific exercise it is not perfect. It is conducted by volunteers, so the accurate identification of species is only as good as the volunteers’ knowledge can be. To be fair, participants tend to be keen local divers (at least in the group I’ve joined) who are probably familiar with the local species; and for the others it’s a good opportunity to learn.
Another challenge is that individual team leaders need to lay their transect at the exact same spot every year for the data sample to become meaningful over time. There is no point in looking at the change in coral coverage over time if the corals recorded are not the same as those that were surveyed during previous checks! Therefore it’s important for the organiser to have excellent knowledge of the site, GPS coordinates and so on.
Finally, the transect method serves to take a measurable sample, but it remains a very small sample of a very small area. Species diversity varies greatly with depth and in different zones of a given site, as we experienced on Sunday. I think the reef check results could be further enhanced if, in addition to the transect survey, divers carried out a broader fish/marine life survey across the whole site, which would generate a less focused but more comprehensive snapshot of marine diversity of the site. Conducting the 100-metre transect survey does not take long; divers could use the rest of their dive time to conduct this wider species survey. It would be a good way to get more divers involved and would have an educational dimension too.
Overall though, like the coral restoration project I recently took part in, participating in the reef check certainly has a positive impact on the participants, since it encourages us to look a lot more closely at the marine life around us as we dive.
If you enjoyed this post, please do follow this site by ‘liking’ its facebook page to receive future updates, or subscribe by email (scroll down, bottom right). Thank you!