Like this:

Rose Garden is still throwing up all kinds of surprises. Our urchin predation assessment has just rolled around once again, with staff and volunteers spending two days collecting and spearing urchins, stringing them up to entice various fish with an easy meal, and then looking at the remains of their spiny little bodies to figure out what sorts of urchin-eaters there are out there. And of course Rose Garden, the marine reserve, is one of our survey sites.

We have moored up on the north eastern side of the reef and I’m sunning myself on the boat. The volunteers have located the lines without my help, the viz. is good, the conditions clement. It’s a rare chance to take 20 minutes in the sunshine, and I’m teaching Manjo, our legendary boat captain, some maths.

As the urchin team heads back, one of them spots something. “There’s a guitar shark down here!” Really…?!I’m sceptical and consider staying on the boat; warm and dry.

But then I recall Kris, long term volunteer and excellent SCUBA student, telling me about a guitar fish that had supposedly visited him at Ankaranjelita while he was waiting on his knees for me to run through a navigation exercise with another student. I was sceptical then, too. But curiosity gets the better of me; two suspected guitar sharks in a week? This needs confirmation.

So in I get (the water turns out to be quite nice, actually, not too cold at all), mask fins and all, and yes, there is indeed a young guitar shark resting buried up to his eyeballs in the sand at the bottom of the mooring line. Like gannets we dive down, taking turns for a closer look.  The water is only about six meters deep and so the free-diving is relatively easy, but we pass a one kilo block between us so that we can stay on the bottom for a few seconds longer. The guitar shark appears unperturbed by our presence, seemingly quite confident in the infallibility of his sandy disguise.

Guitar fish, or guitar sharks, are members of the Elasmobranch sub-class, a taxonomic group that encompasses all rays and sharks. This is not a common sighting. So far, the only other members of this category that I have encountered here have been rays; blue spotted, torpedo, and one suspected coffin ray.

I gently waft the sand from one of his pectoral fins to determine colour and pattern so that we can identify what species this individual belongs to. I reveal a small patch of greyish brown skin dotted with darker-margined pale spots. Again, no reaction from the fish in the sand; confident little Elasmobranch….

Guitar fish are so named for the obvious reason that their bodies are shaped like electric guitars of the glam-rock variety. They have long, pointed, flattened snouts which taper back to wide pectoral fins. Pelvic fins are also flat and protrude just behind the pectorals along the sides of their bodies. Their dorsal fins are situated far back on the tail; eyes are close together on the top of their compressed heads, giving them a slightly woebegone appearance. And while their mouths and nostrils are tucked underneath them against the sand, as with many rays, they move like sharks with sinuous stokes of their tail and caudal fin. These wonderful hybrids tend to prefer sandy, shallow, inshore coastal habitats such as sea grass meadows and mangroves, where they can prey on crustaceans, molluscs, and fish.

The guitarfish family comprises 4 genera and over 40 species.  Back at base, identification becomes tricky. The pattern of spots is similar to the Ringed guitarfish Rhinobatos annulatus, yet the body shape does not look quite right. Our fish has wider, more pronounced, ray-like pectoral fins. The White-spotted guitarfish seems to have a more similar pectoral morphology, but the distribution does not fit. Trawling through the web, we come across reports of Rhinobatus petiti, a rare and as yet undescribed species of guitar fish that has been caught only once off the Toliara coast. With no morphological description or photograph to consult, we briefly entertain dreams of having encountered a relatively new and undocumented species of elasmobranch. Unlikely.

So the jury is still out. We are going to have to run into this odd-shaped elasmobranch once again, this time while carrying a camera. From now on, it looks like I will be spending most of my dives at Rose Garden with my eyes glued to the sand….

Alice Grainger

Dive Officer

Advertisement