It’s strange to think that it’s been over two weeks since I left the distinct life of Mo’orea in French Polynesia to return to the bustle of Vancouver: from a single road to multitudes of roads I still don’t know the names of; from sun, water, fresh pineapple, and lush volcanic peaks, to well, something similar yet quite different – sun, water, lush volcanic peaks and no fresh pineapple!
Since returning back to our respective homes, the team studying the eating habits of a particular octopus species living in waters halfway around the world has started to sort through data and notes we collected, and to think about what conclusions we can draw from what we found.
So, can I tell you now what O. cynea (the day octopus) likes to eat? Not quite yet.
Over the course of our 21 days of research, we spent roughly 50 hours searching the azure waters looking for those quirky characters or places that make up each unique octopus neighborhood. All told, we have data from five different sites (though we scouted perhaps 13 different habitat sites during our stay). We met more than 25 octopuses and – in keeping with modern life – we ‘poked’ them to test their personalities (note – do not try this at home). And once we had scratched around their neighbourhoods and cleaned up their dinner plates, we recorded 244 prey items in our database.
Sorting, analyzing and interpreting all this data is going to take some time.
One of the things I can tell you is that the dominant prey species we came across were the clam (quidnipagus palatum), the crab (daria perlata), the tree mussel (isognoma perna) and the crab cyclodius obscurus. Even being able to come to this finding took hours of sorting through piles of shells (called “middens”). In addition to the four main ‘dishes’ listed above, we found another 40-60 other species in the octopus middens – and we still have some shells yet to be identified.
As I mentioned in a previous post, one of those 40-60 species is the Gonioinfradens paucidentatus crab – and this crab was confirmed by Joseph Poupin (a French marine biologist who maintains a database of these animals) to be the first recorded crab from Mo’orea. Although this crab is common in the Indo-Pacific, it has never been officially recorded in the waters off Mo’orea before.
Some of the other things we found interesting are that our observed octopuses have a high diversity to their diet, and that where the density of octopuses increases, so does the diversity of their diet.
Once we’ve finished identifying the octopuses dinners and the research paper we planned is written, we’ll take another look at the information we collected on our trip to see what else we can find. In addition to the data we collected about O. cynea prey and diets, we have over a thousand pictures and likely close to a hundred videos (including at least four foraging trips filmed – which is pretty exciting). This information might be enough to create another paper detailing foraging activities of this species.
All in all, we discovered quite a bit on our trip to this beautiful island.
And all those photos? My co-workers will be watching them on my desktop computer background for quite awhile yet.
Guest blog post by Keely Langford, an interpretive delivery specialist at the Vancouver Aquarium. This summer, Keely accompanied a team of researchers, led by Dr. Jennifer Mather of University of Lethbridge, to the South Pacific this summer. This team of researchers is studying how the day octopus (Octopus cyanea) chooses its food. Keely is sharing a series of blog post updates throughout this trip. Her first, second, third, and fourth posts in these series are also available to read.