3..2..1.. take-off

“We're all familiar with birds that are as comfortable diving as they are flying but only one family of fish has made the reverse journey” inform us “The Journal of Experimental Biology”. Reading more about an experiment done at Seoul answers all the questions that query us when we first watched the flyingfish’s flight over the sea. At the work of two scientists of Seoul National University ,that made the aerodynamic experiments, we can read all that interesting things.
"For the first time, we have performed a direct wind-tunnel experiment to investigate the aerodynamic properties of flying-fish flight and provided qualitative and quantitative data for the flying fish flight. Force measurements were performed for the real flyingfish models with different wing morphologies. The aerodynamic performance of flying fish is comparable to those of various bird wings, and the flying fish has some morphological characteristics in common with the aerodynamically designed modern aircrafts. As the lateral dihedral angle of the pectoral fins decreases, the lift coefficient slightly increases. In addition to the enlarged pectoral fins, the large pelvic fins have an important role in enhancing the lift-to-drag ratio and longitudinal static stability. The enhancement of the lift-to-drag ratio from the pelvic fin is attributed to the jet-like flow existing between the pectoral and pelvic fins. For both solid and water surfaces, the drag coefficient decreases and thus the lift-to-drag ratio increases as a result of the ground effect, indicating that the flying fish obtains substantial advantages by gliding close to the sea surface."

Nelly didn’t expect such a rare meeting while she was ascending from a dive at Kardamili region at Southern Greece. Usually she met jellyfishes or schools of small fishes in similar situations. Suddenly she thought that a bird splashed down over her bubbles trying to catch one small fish that moved carefree near her surface. Watching better she thought that the world had turned upside down (like at the POC 3 movie) and the birds come underwater! Ohhh look that fish it has enormous fins that look like wings tried to say at her buddy who swam nearby her. She realized that she was watching a flying fish, a fish that she had first met while fishing with her grandfather when she was child. Fastly she took some very nice pictures and later shared them at the social network. There I saw the pictures and that make me excited because it was the first time that I saw a u/w picture of a flyingfish. That fishes rarely come near the shore to make company at divers as they prefer the open sea. I find it hard enough to descry which specie it is because at Greece there are several similar species of flyingfish. I think it’s the Cheilopogon heterurus but as far as I search I cannot be sure. Thank you Nelly for sending us that pic!

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.