My one and only

2010 has been declared as the year of Biodiversity by the UN.
Hopefully this will actually mean something more than just a "fancy name " for this year.
Marine Biodiversity in the tropics is immense due to the thousands species of coral and
all the animals that are associated with them, that is well known. Here in snowy Greece
(and the rest of the Mediterranean) we have the one and only scleractinian coral that can
form reefs, Cladocora caespitosa.
We might only have one reef building species of coral here, but our seas are as spectacular
as the tropics, only sized down a little bit, but that does not matter! (Dive Greece Baby!)


Cladocora caespitosa

This amazing coral can form colonies up to 1m in diameter and one big colony was discovered
some years ago on a reef in Vourvourou, Chalkidiki(hope it's still there!)! As most corals, it is
composed of an external, calcareous skeleton which is secreted by the living organism contained
within it. The individual coral polyps(the little tentacles that are visible in the picture above) are
symbiotic with algal zooxanthellae, which photosynthesize to produce nutrients for its host.
The Cladocora coral reproduces sexually, releasing orange eggs and bundles of sperm before the
full moon in the summer months, in the Adriatic banks of this coral this happened in June.
The shape of the colonies depend on depth, light and currents.
It has a growth rate of a few mm per year, making it extremely slow growing.

Diving in Pilion last summer we were shocked to find massive coral structures completely
torn to bits at a depth of 40 meters.


The first time I encountered these massive formations and they were all dead....
Vizualising these corals when they were alive and the life they contained within and around them
is wondrous, but for the sake of biodiversity and for a healthy ecosystem...
I hope this year we permit our one and only reef building coral to grow.

the hermitcloak or anemocrab?

In an older post we talked about the association of Dardanus sp. with the anemone C.parasitica. Now I will describe to you the most admirable symbiosis relationship of the Mediterranean, between crabs and anthozoa. Pagurus prideaux is a hermit crab that can grow up to 6cm and lives usually on the sandy parts of cave entrances. Unlike their great population in the Norwegian coast of the Mediterranean you cannot meet them too often here. When they are young they start to have a symbiotic relationship with the Adamsia carciniopados anemone. Because P.prideaux doesn’t feel very comfortable inside the gastropod shell, they prefer to live with “something like a shell” which the anemone helps to build. That way it doesn’t need to change its shell throughout his lifetime, as the shell grows bigger, along with the crab and the anemone. The anemone covers all the sensitive parts of the crab and the tiny shell like a cloak. The anemone is responsible for her buddies defence. For that purpose when they are in danger the anemone produces a lot of bright pink tentacles with stinging cells. These tentacles are called “acontia” (Second photo “where these animals are frightened the crab runs as the anemone spreads its stinking defence). The most noticeable thing in this relationship is the feeding behaviour. The crab feeds the anemone by putting pieces of food near the anemones mouth! It is possible, even after a few hours, the crab pulls the food out of the anemone’s stomach and eats it.

Crab duo...

Spidercrabs love anemones, and the anemones love the crabs. It seems that neither animals are hurt in this beneficial relationship, the crab is protected by the poisonous tentacles and the anemone is warned for any predators before anyone can suspect otherwise. You see, these crabs cannot be seen easily, you may be taking a picture of one and the other would be giggling behind a tentacle! Amazing camouflage and very hard in identification, unless the carapace is available for closer examination, for example when the crab is shedding. Maybe next time...I know where you live....
Sometimes they like to cover up with sponges, like another resident of Kalogria which will be on the next post.
Until then happy crab hunting!




Photo taken on this last Sunday of November in Kalogria.

Greater Mediterranean hermit crabs

As most species of crabs Greater Mediterranean hermit crabs are susceptible to fights. Here you can admire the impact of Mike Tyson to the animal kingdom. (Video by Kostas Milonakis, unidentified if they are D.arrosor or D.calidus)


Dardanus calidus with some Calliactis parasitica on his shell.

Dardanus calidus

When you diving at Mediterranean you can meet two species of Big Hermit crabs (Bernard-l'ermites). The species Dardanus arrosor and Dardanus calidus can grow more than 6cm and both can be symbiotic with the anemone Calliactis parasitica. Unlike with the parasitic symbiosis that this anemone has with the Atlantic Hermit crab Pagurus bernhardus it is confirmed that D.arrosor assists the trasfer of C.parasitica to its shell. Also the same experiments showed that most of the D.arrosor that had accepted C.parasitica to their shell were females and males prefer to be on their own.

Funky slug making lurve circles...

The Eastern side of the Mediterranean, never seems to stop suprising us with its beauty!
Phyllidia flava is the only representative of the Phylidias, in the Med,
and here we have two specimens (yellow blob) on the two orange shponges, after they have layed their, not so perfect as usual, egg mases.
Phyllidias do not have radular teeth so these slugs eat the sponge by exuding enzymes and sucking the animal off the sceleton.
This photo was taken at 35 meters in Pilio.

A small city called Anemonia viridis

Living on her own or at big populations Anemonia viridis is one of the most common Mediterranean anthozoa species. It is the home for a big number of other species like crabs, fishes, shrimps even bacteria and algae. So she's is a real ecosystem on her own. The green fluorescent proteinis probably responsible for the ones with greenish colour. You should avoid touching her because as all the cnidarians may damage you with her stinging cells. If you want to meet the residents of this city stay in contact with medi-sea.blogspot.com .

Alicia in wonderland!

This amazing anemone, is so unlike any others!
In the day time it is as shown in the pictures, but at night it extends upwards
with elongated tentacles around it. We promise to post a night shot soon, or if anyone has one all ready and would like to
contribute, please do.
In the day time you can see it attached on anything, sponges, plastics (why are they there?), seaweed, anywhere.
All photos from Pilion, from 5-18m depth

Lung Jelly or Octopus Jelly

- It's the biggest jelly fish species in the Meditarranean sea.
- photo taken from Pileion Greece (trikeri) at march 09