By Iain Caldwell
Thinking back to my recent experience at the IMCC, there is one session in particular that stands out in my memory: “Lessons from the control of invasive species on coral reef ecosystems in Hawaii.”
It seems like doom-and-gloom stories are all too common in conservation and I was buoyed by the positive messages coming out of this series of talks. The first speaker, Jonathan Blodgett from Hawaii’s Department of Land and Natural Resources, talked about how the Hawaii Department of Land and Natural Resources has gained a foothold onAvrainvillea amadelpha, an invasive algae species in Kaneohe Bay, using a giant underwater vacuum cleaner and sea urchins.
The vacuum cleaner (playfully termed the “super-sucker”) is used by scuba divers to suck up the vast tracts of the algae that have invaded the bay. While the super-sucker is good at removing the algae, the area can become re-invaded quite quickly. This is where the cleaner urchin come in. Once the invasive algae has been removed, these native urchins have been successful at keeping at least small areas clear of new algae. The technique is certainly not perfect as the urchins need to be “herded” to areas that need to be cleaned, but it appears to be a step in the right direction.
The second speaker, Eric Conklin of the Nature Conservancy, shared some lessons from his work co-operating with local organizations to rid Oahu’s shore of the same invasive algae species. The lesson he shared that stayed with me was that starting small can make big things possible. Eric showed an aerial photo of Manalua Bay after a group of volunteers had made a first attempt at removing the invasive algae. The algae carpets the bay from one end to the other and a group of local volunteers was only able to clear a tiny square on the map.
As Eric said, it would be very easy to look at the photo and think that their efforts were for nothing. However, that small step inspired a partnership between the Nature Conservancy and a local people’s organization called Malama Maunalua, which has attracted more funding and support. The result? Over 23 acres (almost three million pounds) of the invasive algae have been cleared to date.
The third presentation was a tag-team effort by Russell Sparks and Darla White, both of the Hawaii State Division of Aquatic Resources, who have tackled the algae problem in Maui by protecting key herbivorous fish from overfishing. These native fish eat the algae and help to keep the invasion in check. The Kahekili Herbivore Fisheries Management Area was established in 2009 and has gained local support even within fishing communities — probably partly because fishing of non-herbivorous fish is still allowed.
The final presentation, by Alan Friedlander of the University of Hawaii and the USGS, addressed the problem Hawaii faces from an invasive fish known as roi. This grouper species was initially introduced in the 1950’s as an additional source of food because of the dwindling number of native fish. Ironically, it has since been linked with ciguatera poisoning, making its consumption questionable. It is now blamed for the further decline of native species.
Spearfishing groups have been organizing “roi roundups” to try to rid reefs of the perceived threat of these species — without enough information about the actual threat or how effective this intervention can be. Using a suite of experimental techniques, Alan and his colleagues at the University of Hawaii and the Nature Conservancy have been working with local fishing communities to determine what effects roi is having on the native fish community and whether their short term removal is an effective long-term solution.
Even though the five speakers were from a variety of backgrounds (NGO, government, and academic) they all had a relaxed and conversational tone, which made the session feel more like a town hall meeting or a department seminar than a formal presentation at an international conference. It probably helped that the room was small and the dress was casual — the speakers donned Hawaiian shirts for the occasion — but I think any audience would have been engaged.
To me this refreshing and informative session demonstrated that good science can be entertaining and conservation can use positive messages to inspire.
Iain Caldwell is a Ph.D candidate with Project Seahorse.