news
Bubbles Burst at the Surface
Feb 10, 2012
Huge Pipefish at Vato Soa
As very much a right-brain diver, my appreciation of a reef system relies heavily on an aesthetic sense; on colours, movement, and the patterns created by coral cover and streaming cascades of fish. This, obviously, is not the most scientific way in which to gauge the health and diversity of a patch of ocean.
And yet, as human beings, our sense of beauty is intrinsically connected to our subconscious ability to assess the condition of our environment and the organisms that inhabit it; we instinctively choose a genetically appropriate mate based on the ratios of their physical features, we learnt to determine what fruits were ripe and edible based on their colour, we can infer the well-being of a plant just by looking at the shape, texture, and hue of its leaves, and environments that are potentially bad for our health tend to assault some of our finer senses and repulse us.
And so I am sure that this is why, when diving barren, monochrome reefs that have been badly damaged and are being colonised by bacteria and algae, something registers as deeply disturbing. And I am sure that this subconscious, aesthetic evaluation is also why, when diving at Vato Soa, the soul sings; aware somehow that this place is still enjoying a rich diversity of habitation.
Vato Soa, or ‘Good Rock’, is a site that lies roughly seven kilometres north of the ReefDoctor base. It is shallow, as with most sites on the interior, and, on a good day, the water can be exceptionally clear and delightfully blue. It comprises a triangular formation of three relatively small patches of coral, the tops of which do not extend more than two or three meters from the sea floor.
Vato Soa has, somehow, so far escaped the deleterious effects of over fishing, coral bleaching, and invasive species.
Crowning the reef, huge, dense gardens of foliose Montipora; whirling helix formations best appreciated from above, look like creations inspired by M. C. Escher. Schooling yellow back fusiliers dip and dart overhead. Crevices hide all kinds of elusive fishy treasures such as leaf scorpion fish and crocodile flatheads, numerous species of nudibranch and shy moray eels.
A resident octopus guards his coralline castle, peeking out over the top of shells and rocks meticulously collected and arranged to ridge the lip of his lair.
Near pristine Porites bommies are enveloped in clouds of sweepers and hinge-beak zebra shrimp scuttle around the bubbling boundaries of huge Plerogyra colonies.
Huge pipefish up to twenty centimetres long inhabit the sea grass bordering the site, twiggy heads peering out over the algal canopy.
Getting to Vato Soa requires quite a lot of petrol, which means that we don’t dive it as often as we would like, but it also means that a dive there is a real treat. Thankfully, it is one of our survey sites.
So, on this day, while the urchin predation assessment team were happily analysing and gathering baited lines of urchins, I was to change the data logger with my dive buddy, Kajsa. We were prepared for the worst, having recently had a rather frustrating data-logger ‘session’ at Ankaranjelita.
Ah, changing the data loggers. At this point I feel I need to make a small digression in order to familiarise those of you who may not have not have been fortunate enough to take part in this process.
The data logger is a wonderful little piece of technology that, once carefully and securely situated, tied firmly to a suitably exposed piece of substrate, will record for you all the information about light and temperature fluctuations that your scientific, research orientated heart could desire.
They can be out merrily memorising for around three months, after which they need to be brought back to be relieved of all this data, and another one installed in their place. Quite impressive for a little two inch square piece of plastic. Simple, I hear you cry, so why this hullabaloo?
Because, in addition to being nifty little gatherers of information, the humble data logger is also an accomplished gatherer of algae, and while out on mission will cleverly disguise itself as a living piece of reef. These masters of deception, however, are not always so adept at blending into their surroundings, with some finding themselves so conspicuous as to attract the attentions of passing Vezo fishermen with an eye for foreign technology. So, to cut a long story short, these diminutive instruments can be a real bugger to find.
Incredibly, this time it only took us about 70 minutes to locate the elusive article and so we finished off the air in our second tank with a truly enchanting pootle around this charming site.
We made the acquaintance of the largest red-mouth grouper I have ever had the pleasure of meeting (we have named him Pete), we ‘ooh’d’ and ‘ahh’d’ at scorpion fish and a crocodile flathead, we stared transfixed at a whirling vortex of glassfish. Running low on air we headed back towards the boat; stopping briefly to direct the grateful urchin team to the last of the lines (you’re very welcome).
Arriving at the surface we exchanged happy smiles, and immediately began sharing the highlights of our splendid little dive.
Also resting at the surface, just twenty meters or so from us, were two pirogues. We raised hands in greeting and began to fin back towards Faye. This position afforded us a premium view of the fishermen as they began dropping their huge nets into the water; fishing gear constructed from several hundred square meters of mosquito netting. And as the pirogues made deft manoeuvres, encircling the entire site in the lethal mesh, a site where, mere seconds before, we had been swimming around in a state of blissful amnesia, the reality of the pressures facing the Bay of Ranobe were once again brought crashing home.
Nets of this kind are unbelievably destructive, indiscriminately gathering juveniles as well as by-catch such as damsel fish. It was heart breaking to motor away from the site, leaving behind who-knows-what ichthyologic devastation. Visions of our venerable red-mouth grouper kept popping into my mind, and I prayed that he would have the sense to find a deep crevice and stay put for an hour or so.
From a position of privilege and vegetarianism, it is all very well to feel a sense of tragedy after such an explicit encounter. And yet, daily, we see evidence of the extreme poverty that characterises this region of Madagascar, with people driven, through lack of opportunity and education, to such unsustainable practices in order to survive.
Last week we made a return visit to Vato Soa, and I did catch a fleeting glimpse of old red-mouth Pete. It seemed he had outwitted the nets once again, for at his size, it is more than likely that he has seen nets such as those many, many times in the past.
Given this probability, Vato Soa does not appear to be suffering too badly. At first glance, fish density in general did not seem to be much affected since the last poignant visit, but it would require more stringent monitoring to ascertain just how well the site is handling the fishing pressure.
My intuitive, aesthetic sense tells me that there is still hope for this supposedly highly resilient patch of reef, but, as the science team would say, this kind of thing needs to be quantifiable.
Alice Grainger
Dive Officer
May 2011
