28 Oct 2010

the third, the unknown the luckiest.

While swimming at Chorto bay in the Pagasitic gulf, I had the chance to check the marine life that lives associated with the Aplysina aerophoba sponges. I wasn’t alone, as this tiny fish had the same interests with me. It is the third, the smallest and the most unknown common fish species of the genus Serranus in the Eastern Meditteranean Sea.

Scientists of Ichthyology give it the humble name Serranus hepatus. I don’t think that this defame matters the fish, as its famous cousins are famous because fishermen catch them with hooks. It doesn’t feel unhappy of this because it knows that it’s better being an insignificant swimmer, than fried and famous. You can differentiate it from the Serranus cabrilla by the big black spot on its dorsal fin.

More information about our friend can be found in studies made by Abdoulaye Wague (in Greek click here) and Murat Bilecenoglu (in English and Turkish click here) .

24 Oct 2010

Running to the shelters!

.........................The presence of Elina alerts the hermit crabs.

As the naturalist approaches the sponge,he can notice a lot of tiny shells loosing their balance and falling down. In previous posts we saw the symbiosis (or the vicinity) between the sponge, mollusks and polychaeta. The structure of the sponge Aplysina aerophoba provides shelter also to the third major group of benthic fauna, the crustaceans. The little shells (except some Bittium sp) are the houses of the small hermit crabs. In the macro photo I think that you can see a young Pagurus anachoretus but it is too small to recognize. I was very impressed by the fast and simultaneous reaction of the tiny hermit crabs. As I got close to the sponge, at once all of them left their shell to fall from the walls of the sponge to the lower darker parts of the sponge. I don’t know if there is a possibility of communication between the hermit crabs, but what about the sponge? Sponges don’t have nerves but as an animal they find other ways to inform the rest of the body for what is happening. Maybe there is a sign by the sponge that can be recognized by the crabs? It’s very difficult to know but it’s nice as a scenario. Who knows maybe we learn in the next posts of the blog.

18 Oct 2010

More variable more watchers.

Except from having a great variable of color Hypsolodoris picta (as Elina inform us in the previous post) the nudibranch has and a great variable of cousins. The variable of color can reach to reddish coloration that we can meet at Cape Verde and the whitish coloration that we meet at several areas. The subspecies dividing of the species is ambiguous as the distribution of the species doesn’t match with the biologic taxonomy of the subspecies. In the photo above that provided to us by Konstantinos Vatikiotis we can admire an individual of the genus Hypselodoris (probably Hypselodoris villafranca but there is and a possibility to be a juvenile of H.picta). At the photos lower you can see more H.picta coloration and patterns. Have a look along with Frank!
First and second pic above from Santa Maria Paros, the third one is from Emporios bay Chios and the right above is from Kelifos island at Chalkidiki. All this locations are at Aegean sea.

15 Oct 2010

Variable colored beauty of the sea

The sea is full of suprises, we have seen this by now many times, but what never seems to astonish me is the suprises we find when we least expect them. Like yesterday for example, I dove in 4 meters of water in the muddy straight between Galatas and Poros, for training purposes.. I never go in the water without my one and only small camera, just for those suprises...and look what I found!
The beautiful Hypselodoris picta

This chromodorid is the largest of all chromodorids in the Mediterranean, reaching a size of 20 cm and it's distribution reaches as far as the Eastern Atlantic.
Because of its chromatic variations, this species has changed many names with the most common synonym being Hypselodoris elegans.
Nowdays, it has at least 5 subspecies depending on its locality and color.
This magnificent slug prefers to eat various sponges but its favorite food are sponges of the genus Dysidea.

8 Oct 2010

Pompanos as companions

This summer, never was I lonely on the shallow dives. The minute I jumped in the water 3 beautiful Pompanos(Trachinotus ovatus, Litsa, Mavrolitsa or Gofari in Greek) appeared immediately and were our loyal followers throughout the dive. They swim very fast, in a most elegant fashion and their curiosity is high, coming very close to swimmers without fear.
Their tail is fork shaped as is typical of the carangids, with a black spot on the tip of the caudal, dorsal and anal fins. They also have 3 - 5 dark spots on the front end of their body. The biggest specimen recorded was measured at 70 cm, although most commonly at 35 cm. Its distribution has been recorded from the Eastern Atlantic, Bay of Biscay, British and Scandinavian waters (rare) to Angola, including the Mediterranean Sea and offshore islands.
They usually swim in small schools near the coast in shallow waters, over sandy or muddy bottoms, unlike their other relatives of the amazing family Carangidae, which are mostly pelagic. They mostly prefer to eat small crustaceans, mollusks and fishes.
For this reason they are easy to spot and photograph.
Pompanos have a high salinity tolerance and are in the process of being farmed in China although they have a low food conversion rate, with trials being made to grow them using soyabean and fishmeal.