By Dr. Phil Molloy
When I tell people that I do coral-reef conservation, they usually tease me about the tough life I must lead, spending all that time in the sea, sun, and sand. If only it were so relaxing! In fact, my work tracking the changes in fish populations starts with days of poring over species identification guides, shifting dive gear on and off boats, making seemingly endless forays to and from field sites, and spending hours underwater, wishing I’d gone with the 5 mm wetsuit instead of the 3 mm one.
Don’t get me wrong: I love it. I wouldn’t be doing reef conservation if I didn’t. But the widely unrecognized reality is that marine conservation fieldwork is time-consuming, physically demanding and, critically, expensive. Yet it is work that must be done carefully and accurately. Without accurate studies of the impact of external pressures on marine ecosystems, or the effectiveness of marine protected areas, we wouldn’t be able to create better conservation tools.
So, as marine conservationists, we are under considerable pressure to develop quick and cheap methods that allow us to get in the water, collect the data we require and get back to terra firma.
To this end, I’ve been exploring ways to streamline the methods used to detect changes in coral-reef fish populations over time. Can we, for example, obtain meaningful results even if we reduce the frequency of visits to each study site or the amount of replication required each visit, or by considering just a handful of fish species? In particular, we were hopeful that we could detect general changes in fish populations using a subset of locally fished species or those whose names make them particularly easy to identify (like the blackfin barracuda — a barracuda with, you guessed it, black fins).
By re-analyzing an existing dataset, we found that we could still detect changes in the number of fish and the number of species if we visited sites every other month (instead of monthly), or by halving the amount of replication done each visit. Most interestingly, we also found that we could detect these changes by only considering three-quarters of the locally fished species or all easily identified species. Still with me?
What this means is that we don’t need to count every fish species to detect changes in the overall fish populations on the reef. By using commonly fished species as indicators, conservationists can reduce the amount of time and money needed to train research volunteers — and they can more easily involve local fishers in their fieldwork, making it faster and more effective!
This is good news all around. Our results mean that we’ll have more time to do more conservation, and maybe, just maybe, a little more time to enjoy that fabled sea, sun, and sand!
Dr. Phil Molloy is a postdoctoral fellow with Project Seahorse. Learn more about this research in “Frugal conservation: What does it take to detect changes in fish populations?” published in the November 2010 issue of Biological Conservation.