Coral Reefs

Secret Biodiversity: Uncovering Hidden Species and Behaviours

Secret Biodiversity: Uncovering Hidden Species and Behaviours

The second of the new marine science seminar series was held online on Tuesday 13th October. This session looked at ‘Secret Biodiversity: Uncovering Hidden Species and Behaviours’ and featured a fantastic panel of international experts chaired by Dr Dominic Andradi-Brown of WWF.

A recording of the seminar is available to watch here:

Here are answers to some of the remaining questions which there wasn’t time to answer during the live session.

Have you noticed any specific behaviours between shark clans or pairs that may be acting to keep their social bonds strong? An equivalent to grooming in primates so to speak!

David Jacoby: With the technology we are working with acoustic telemetry we are already pushing the boundaries of what we can understand about behaviour. Our techniques are inference methods as we cannot actually directly measure social behaviour in the same way that we would for grooming interactions in primates. The challenge we face is studying animals that we will never see again and that travel long distances under water – hence the combined approaches of the camera tags with the acoustic tags. We’ve done a little work on leadership in these sharks and find that females are more likely to lead away from the reef than males who are more likely to follow. I would say that strong social bonds are maintained by the duration of time these individuals spend together. I really does seem as though they have quite tight knit communities. Hopefully the technology will progress sufficiently soon that we can measure and importantly retrieve data on direct social interactions in wild sharks.

Are there other species of sharks known to have the similar social groups such as grey reef sharks?

David Jacoby: There are a number of other species that have been shown to be social including (but not limited to) manta rays, blacktip reef sharks, small spotted catsharks, lemon sharks etc. So, it seems that social behaviour is not necessarily uncommon in sharks. The study I presented is the first however to suggest that sharks can maintain social preferences over many years, and that perhaps the mechanism driving structure is one of information exchange about foraging locations.

Is there any ex situ conservation work on Chagos brain coral? Would an in situ conservation intervention be possible?

Bryan Wilson: A great question, essentially underpinning the biggest challenge to my research at the moment, here at the University of Oxford. The Chagos Marine Protected Area is a wonderfully difficult location to get to but I’m always so very aware that it is this remoteness that drives its incredible biodiversity. And in that regard, both in situ and ex situ conservation work on the Chagos brain coral are inherently “difficult”. Limited access to the area means that the regular monitoring and management that in situ work would require is problematic, whilst the administrative (and not least, ethical) issues of removing and transporting critically endangered species overseas for studies are a major concern. However, I’m spending a good deal of my time looking into how we might solve these critical problems – and collecting gametes and/or larvae from spawning Ctenella chagius for ex situ conservation seems to be the most logical way forward, essentially minimising physical perturbation of the adult colonies in situ, whilst also allowing for a more amenable means of transporting live biological specimens out of the territory. I’m hoping that with the wonderful ongoing collaboration and support of the Zoological Society of London and Horniman Museum and Gardens, we shall ultimately be successful in this venture!

Is the amount of boring algae associated with the health of the corals?

Bryan Wilson: Another very pertinent question and absolutely on my current research radar – the data that I presented during the presentation is very much at the cutting edge of what we know about this species and as I only received this microbiome data back very recently, I haven’t as of yet had the time to fully delve into it. Major biological and ecological statements will also have to be tempered by my small (N = 7) sample number – however, with the serendipitous discovery of this “Aladdin’s Cave” of colonies in the northern atolls, I am relishing the opportunity to return the MPA and sample more extensively.

Do if you think the Chagos brain coral could be the panda of coral reefs? Or does it represent the general survival chances of Chagos coral reefs?

Bryan Wilson: That’s a salient point and one that I’ve discussed with many of my colleagues. Whilst I won’t deny that I have become very attached to the idea (bordering on all-consuming passion!) of conserving this iconic species, it’s important to place this coral – like Giant Pandas – in the greater contextual framework of an environment under stress. We’re seeing the degradation of reefs on a global scale, and the reduction and loss of a number of coral species – in the Chagos MPA, Ctenella chagius is the species most threatened, teetering on the very brink of extinction – but other coral species will surely follow in the years to come if we don’t act now. And so I believe that if we can save Ctenella and put in place a conservation framework to recover corals such as these, then we may have a greater chance of halting the decline in biodiversity on these reefs.

Is there any work being done on the presence of potential toxins from manmade sources like agricultural pesticides and herbicides in the water around the Chagos Archipelago?

Currently this work is not funded as part of this marine science programme but there is interest in developing this work in the near future.