28 Nov 2010

Sandy bottom delights

This time we were looking for sea horses but instead we found rays, many many rays!
The sandy bottom realm sounds quite boring, divers stay well away of it, but the sandy bottom hosts an array of very interesting and beautiful inhabitants. Today we present the skate/ray Raja radula,one of the most common rays of the Mediterranean,with some evidence towards its endemism in the area, as the specimens found off the Atlantic could have been misidentified with other similar species, not very hard to do with these rays.
This ray is completely harmless to humans, it has no thorn, like the sting rays and no electricity like the torpedo rays, however the skin around the tail is quite rough, hence its common name, rough ray.
This fish inhabits shallow water until the depths of 300 meters,and this particular specimen was photographed in Stratoni at the depth of 10 meters.All in all, on a 50 minute dive, we spotted 4 animals laying on the sandy sea bottom.
They prefer to eat any type of bottom animals, making Stratoni a haven of food for them!
They are oviparous, laying oblong egg capsules with stiff pointy horns on the ends (mermaid purses). About 80-154 eggs are laid by an individual in a year. Because of insufficient data on their populations it is listed as Data Deficient on the IUCN Red List.

3 Nov 2010

Triggerfish journeys

Photo by Vasilis Mentogiannis

After all these years of diving, travelling and exploring the seas of the world, this was the year I said with the most certainty that even if I only dive here,in Greece, for the rest of my life and nowhere else, I will be happy and content!
Dive Greece Baby!
The beauty of our sea is not only very well hidden and currently very fragile but also it is very little acknowledged. One example, is a completely exotic animal the Triggerfish, which usually lives in tropical seas. The Grey triggerfish (Γουρονόψαρο η Βαλιστής) is a resident of the East and West Atlantic, all the way down to Argentina with rarer occurrences in the East Mediterranean.

Balistidae is a family containing 40 species but only Balistes carolinensis (synonym Ballistes capriscus)can be found in Greece. As a family, these fish are most extraordinary, with colorful lines and spots, especially in their Indopacific range. Their name, triggerfish, comes from the locking mechanism of their anterior dorsal fin, which is composed of 3 spines that fit inside a groove, while only 2 work as a trigger. When the first, (anterior) spine is locked in place by erection of the short second spine, then it can only be unlocked by depressing the second, “trigger” spine.

Another peculiarity of the triggerfish, is their aggressive behavior against other fish in small aquaria, or divers when they approach a nest of eggs. At this point, it is advisable to swim away from the nest and not over it, as their territory is conical reaching to the surface. If you add the aggressive behavior of these fish, along with their strong, fused teeth, you have one vicious, unnecessary bite! Some strong attacks have been mentioned from bigger, more tropical species, but for the Grey triggerfish this has not been reported.
Balistes carolinensis prefer to eat small crustaceans and mollusks from the benthos. Their skin is very tough and leathery.
It seems that this particular individual is a juvenile, because the tips of its caudal fin are not elongated yet। As an adult it can reach the size of 60cm! Their reproductive season is in the summer, when spawn is placed inside a crater on the sand, and is guarded by the female (male in the tropics), a sure sign you should swim around and not over the nest!
The color of the Grey triggerfish is mostly grey with brilliant fluorescent turquoise dots on upper half of body and median fins, and irregular short lines ventrally. There may also be three faint irregular broad dark bars on body and a narrow pale transverse band on the chin.

This particular beauty was hanging out under the traditional fishing boat (kaiki) Agios Nikolaos, the boat that broke the embargo to Gaza in the summer of 2008 http://www.youtube.com/watch?v=8gRscVeNbDo&feature=related.
The second expedition took place this year with tragic consequences....

The boat was anchored next to the Isle of Modi in the NE Peloponnese, but that is a whole different adventure soon to come on Medi Sea!
Until then, thank you Vasilis for capturing the elusive fish!