Some species

emblematic of the Mediterranean

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Black (or brown) grouper

Epinephelus marginatus

Family  :

Sea perch, serranids

 

There are other varieties such as the badèche, gray, royal grouper ...  

 

It is a protected species whose fishing has been prohibited since 1993.

 

Description  :

Bony fish with small scales, up to 1.40 meters in length for a weight of 65 kg, with an oval body, massive, chocolate brown with yellow spots. But its livery may vary. The mouth is wide, the mandible prominent and the operculum bear 3 spines.

The fins have thorny rays.

 

Place of life  :

Benthic and vagile, it lives alone between 20 and 200 meters deep, near the bottom, in boulders, scree, rugged rocky areas that offer several holes in the center of a hunting territory that it traverses and defends. fiercely.

Feeds on  :

It is a voracious zoophage consumer who hunts on the lookout, crabs, cuttlefish, octopus, squid but also rock fish or open water. This stocky and powerful macrophage predator (prey kid-eater) has well-developed eyes, very sensitive scent dimples, a lateral line that reacts to vibrations and changes in water pressure.

It can hunt at night and surprise its prey all the more easily as it is capable of lightning starts.

Its widely slit mouth bears numerous small teeth on the jaws and palate; these teeth are retention organs that serve to hold the prey and prevent it from fleeing.

 

How to observe it while diving  :

It seems that the activity and movements of groupers increase in summer, while in winter the movements are more frequent but of low amplitude; which would be an argument of a real sedentary lifestyle in winter. Thanks to these partial protection measures and the improvement of water quality, in marine protected areas first (Port Cros, Banyuls, Scandola, Bouches de Bonifacio) then outside these areas, the grouper populations s 'grow and rejuvenate (arrival of young females and appearance of juveniles born on the coasts of Provence).  

They are easily observed in open water, they are quite curious and can be approached.

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Red coral

Corallium rubrum

Family :

Cnidarians

Description  :

"  Flower animals  », They form arborescent colonies, ramified in all planes, of variable size (20 cm in the Mediterranean) fixed (sessile species) on dark rocky bottoms (benthic species).

It reproduces sexually, the colonies being hermaphrodite. Fertilization is external and the egg gives rise to a ciliated larva or planula which attaches itself to a hard substrate and gives rise to a small polyp which forms by budding a colony. Growth is very slow.

 

Place of life  :

Species which lead a benthic life, permanently fixed (sessile species) on the walls of semi-dark caves of the circalittoral level (30m) and deeper rocky cliffs.

However, it was found that well-lit colonies were often lush!

 

Feeds on  :

It is a predatory zoophage microphage consumer (= carnivore) which captures small planktonic preys using the tentacles of the polyps which constitute a fine network which filters sea water and retains eggs, larvae, copepod crustaceans .. but also inert organic particles; also it is considered as a passive filter (= suspensivore).

 

How to observe it while diving  :

Red coral also needs clear, agitated water at an average temperature of 15 ° C; its distribution in the Mediterranean is therefore quite limited.

Formerly it was found at depths of 30-40 meters on overhangs, lining the walls of caves in quiet, poorly lit surroundings.  

Harvested since ancient times, "Mediterranean red gold" has become rare today in the northern Mediterranean.  

It is a protected species whose fishing is highly regulated.

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Moray eel

Muraena helena

Family  :

Anguilliformes

Description  :

  Being able to reach 1.50 m, its meeting is sought by the divers. It is characterized by a small brown head spotted with ocher and this coloration transforms along the flanks into a more marked golden marbling. Long dorsal and anal fins merge into a rounded caudal (no pectoral fin)

 

Place of life  :

  Moray eels can be seen along the coasts between shallow rocks and wrecks.

 

Feeds on  :

  Nocturnal, it feeds on fish, octopus, corpses and waste. Its bite is not poisonous but it is nonetheless painful due to the delicacy of its teeth.

 

How to observe it while diving  :

  It tends to feed rather at night. Usually a few symbiotic shrimp live in the same hole, cleansing it of its parasites. Often open mouth when approaching too close, ready to defend against predators (humans)  : watch your fingers  ! 

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Peacock Girelle

Thalassoma pavo

Family  :

Labridae

 

Description  :

Bony fish with spiny rayed fins, slender body covered with small scales. On the sides, 5 thin blue-green transverse bands.

The dorsal fin is long, the caudal has 2 slender lobes.

The head, striped in blue, is small with a pointed muzzle and a small mouth with big lips.

Male and female are of different color, it is said that there is sexual dichromism.

The male besides a "bump" on the head, has a blue-green livery with 2 transverse bands, one blue, the other yellowish.

The orange-yellow female has 5 blue transverse bands and 1 black spot on the back.

Place of life  :

Burrows into the sand at nightfall, when the waters are cold, or to escape an enemy.

Feeds on  :

Carnivorous, predatory fish, it feeds on invertebrates, crustaceans, molluscs, worms that it captures

 

How to observe it while diving  :

Benthic, solitary or in small groups, it inhabits seaweed meadows, Posidonia meadows and rocky bottoms in the hottest surface areas.

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Hervia

Cratena peregrina

Family  :

Molluscs, nudibranchs

 

Description  :

This nudibranch, Gastropod Mollusk, has the appearance of a slug 10 to 30 mm long, which crawls on its flattened foot in sole.

The head has 2 pairs of tentacles  ; the first tapered pearly white which are mouth tentacles, the second erect red or purplish made up of 2 olfactory tentacles or rhinophores at the base of which are 2 orange-red eye spots.

The soft shellless body carries groups of dorsal papillae or cerata which play several roles, bare gills (= nudibranch) and defense organs

 

Place of life  :

It moves on the rocky drop offs of the coralligenous in the Mediterranean in clear and well oxygenated waters: it is a vagile benthic species

Attacked, the slug launch on its enemy the nematocysts which release their toxic venom (actinocongestin) against which it is immune.

Sea slugs have another defense, they taste bad  !

 

Feeds on  :

Hervai grazes the Hydraires (Eudendrium ramosum) on which she lives and shreds them using her radula (long ribbon of chitin with many small teeth): he is a predatory zoophage consumer.

The stinging cells (nematoblasts) of these hydraires are not digested but accumulate in a pocket (= cnidosac) located near the top of the dorsal papillae

 

How to observe it while diving  :

Who finds what Hervia eats, finds Hervia! It is useful to bring a small magnifying glass to better observe it.

There are also several thousand varieties of nudibranch. We observe about twenty common species on our northern Mediterranean coralligenous.

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Octopus (or octopus)

Musk: Eledone moschata 

And common: Octopus vulgaris

Family  :

Molluscs, cephalopods

Common octopus  : 2 lines of suction cups

  Musk octopus  : 1 line of suction cups

 

Description  :

It is a soft-bodied animal, covered with mucus, lacking a fin and an internal shell. The head with 2 well-developed eyes wears a crown of 8 tentacles (= Octopod) located around the mouth: it is a Cephalopod Mollusk. The side arms are longer than the back and front arms.  Like its eyes, its brain is also evolved since the octopus is capable of learning.

 

Place of life  :

It is a benthic animal that does not move far from the bottom where it moves by crawling on its suckers or in open water by expelling water from the palleal cavity.

Solitary, he lives in rocky crevices whose entrance he camouflages with stones, in the upper coastal zone. It is a sedentary benthic animal that inhabits rocky bottoms or the Posidonia meadows.

 

Feeds on  :

The octopus is a voracious zoophage (carnivorous) macrophage consumer that hunts for fish and crustaceans (which it attacks by surprise). It is a nocturnal predator (consumers of living prey). It has a feeding behavior characterized by a series of actions that take place in a given order.

 

How to observe it while diving  :

It is easy to find the octopuses in the rocky holes, in front of which one can observe a heap of small stones which he gathers to protect his cavity, and the remains of small shells consumed.

There remains a fearful animal that must be left in peace, especially during the laying period

To defend  : the escape  ! leaving a cloud of black ink to hide. His worst enemy  : the moray eel.

 

 

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To Spirograph

Spirographis spallanzani

Family  :

Sedentary polychaete

Description  :

Ringed worm, the body of which is formed of segments, living in a soft tube, formed of mucus and clumped mud.

A plume of variegated filaments striped white, yellow or brown, attached to the article in front of the mouth, comes out of the tube and retracts at the slightest alert; this plume consists of two lobes, one of which winds in a helix

 

Place of life  :

  It is a sedentary Polychete Annelid which lives in a tube fixed on the bottom (benthic sessile species): it colonizes poorly lit rocky bottoms but also soft bottoms; the sands and silts of port areas with waters rich in organic matter and plankton.

 

Feeds on  :

The plume of filaments has a dual respiratory and nourishing role.

The filaments constitute a gill which is used to collect food made up of microscopic particles suspended in water which are agglomerated by a secretion; the spirograph is a microphage suspensivore consumer.

What is edible (algae, bacteria) is ingested, what is not is excreted towards the base of the tube and then expelled upwards through a ciliated gutter.

Spirographs are oviparous and the eggs give rise to ciliated larvae or trochophores.

 

How to observe it while diving  :

Often found in caves and caverns, you have to approach very slowly and stabilize yourself if you want to observe the spirograph, because at the slightest vibration (even from our bubbles) it retracts into its tube to protect itself.

 

Animal approaching  : la Sabelle

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Lobster

Palinurus vulgaris

Family  :

Shellfish

Description  :

The red to purple colored body can reach 50 cm in length; it is segmented and has articulated appendages: the lobster belongs to the Branch of the Articulates or Arthropods.

The body is covered with a chitinous shell impregnated with limestone; it consists of two clearly distinct parts, the cephalothorax and the abdomen.

Place of life  :

Benthic animal, it lives on rocky bottoms, drop offs or underwater caves with little light, between 20 and 70 meters deep or even sandy bottoms; it is relatively free with regard to the substance and its nature.

Feeds on  :

During the day, it is hidden (thanks to its homochromy, it harmonizes its color with that of the background and easily merges with the environment); at night, she is active in fetching her food. It is a predatory zoophage consumer that attacks living prey (bivalves, gastropods, sea urchins, brittle stars, etc.) but also feeds on animal corpses (in this sense it is a scavenger) or on plant debris.

 

How to observe it while diving  :

She walks on the bottom  ; when threatened, she makes a sudden leap backwards, beating the water downwards with her swimming paddle located at the end of her abdomen.

It is easy to spot it with its long antennae sticking out a bit from its hole.

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Posidonia

See the article  dedicated on the Blog at this address:

https://dede789.wixsite.com/saphir-plongee/post/la-posidonie-la-forêt-sous-la-mer-méditerranée

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Brown lionfish or capon

Scorpaena scrofa

Family  :

Rascasse, scorpenidae

Description  :

Bony fish, brownish gray or reddish in color with black spots, up to 30 cm long. The body is short and stocky, covered with fine, interlocking scales. The head, devoid of scales, is armored with dermal bones, and bristling with ridges and thorns; the sub ocular bone has 2 sharp points and the supra ocular bone a long and "feathery" tentacle.

The fins are armed with spiny ossified rays; the dorsal fin has a long spine and a shorter flexible part; it communicates with a gland with a poisonous secretion which makes the wound stinging and painful, sometimes followed by edema.

 

Place of life  :

Benthic, solitary and sedentary fish that lives on rocky bottoms covered with algae meadows and mainly on sandy bottoms of the posidonia meadows of the infralittoral level

 

Feeds on  :

It is a nocturnal species that hunts on the lookout at dusk. It is a consumer, predator, voracious macrophage carnivore; its mouth-trap which is enormous, provided with fine and numerous teeth ("velvet" teeth) which cover the jaws and the palate, is capable of swallowing large prey, fish (gobies, blennies ...), crabs, crustaceans, worms, molluscs

 

How to observe it while diving  :  

It is totally invisible on the bottom because it is often motionless and its mimicry is remarkable; mimicry being the resemblance of an organism to another species or to the substrate. The lionfish, thanks to numerous anatomical details, cutaneous appendages on the head in particular and on the body, merges with the rock covered with algae. A lamp is necessary to see it well.

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Gorgon

Paramuricea clavata

Family  :

Cnidaria, Paramuricea

 

Description  :

Colonial multicellular animals (Eumetazoans) resulting from an embryo with 2 layers the ectoderm and the endoderm which will give on the one hand the external wall and on the other hand the internal wall with digestive function of the body of individuals called polyps; these have the shape of a "double-walled bag"

The colonies are hermaphroditic (male and female) and the sex cells or gametes are released into seawater; fertilization is external and the eggs give birth to small ciliated planktonic larvae (planula) which after metamorphosis attach themselves to the rocks.

 

Place of life  :

It forms large colonies, up to 30 cm high, fan-shaped, abundantly branched in the same plane, yellow, orange, red or purple in color, living between 30 and 35 meters deep, fixed (sessile species) on rocky bottoms (benthic species) very sloping or drooping

Gorgonians include 21 species in the Mediterranean, including:

  Corallium rubrum or Mediterranean red coral, Eunicella cavolinii or yellow fan-shaped gorgonian.

 

Feeds on  :

The colonies are arranged perpendicular to the direction of the dominant current, which allows them to effectively filter water and retain only the microscopic prey constituting their food; it is a predatory zoophage consumer who captures living prey, plankton microorganisms (microscopic larvae algae, small crustaceans.) but also inert organic particles, which they swallow whole. It is a macrophage

How to observe it while diving  :

By observing more closely with a magnifying glass, one can observe the polyps  :

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The Conger

Leave leave

Family  :

Anguilliformes

Description  :

  This blue-gray, cylindrical fish, reaching over two meters in length, is also called a sea eel.

Serpent-like body, without scales, with a single long dorsal fin, linked to the caudal and anal fin.  

 

Place of life  :

  Common throughout the region, it lives more in caves, crevices, faults in rocks.

Little is known about its reproduction at home, knowing that it migrates in deep waters where each individual lays several thousand eggs and the young take 2 to 3 years to return to the coastal habitat.

 

Feeds on  : 

With powerful jaws, it feeds on crustaceans and small fish

How to observe it while diving  :

 

In addition to its usual places of life, it is often found in wrecks where an abundance of long pipes allows it to hide.

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Girelle or damsel

Coris Julis

Family  : Labridae

Description  :

A bony fish with spiny rays, a slender body covered with small scales.

The head is small with a pointed muzzle and a small mouth with protractile lips. It can reach 10 to 25 cm.

The operculum bears a blue stain.

On the flanks, a bright red or orange longitudinal line and a black spot. The dorsal fin has 8-10 spiny rays longer than the others.

 

Place of life  :

Lives in small groups, it is a gregarious fish whose juveniles inhabit the meadows of algae, the herbarium of Posidonia while the adults meet on rocky bottoms: it is a benthic fish.

 

Feeds on  :

Carnivorous consumer, macrophage, predator that feeds on crustaceans, molluscs, worms that it captures; it has pointed incisors and pharyngeal teeth welded into masticatory blades.

 

How to observe it while diving  :

Very curious by day, and can be easily attracted by scratching a rock with a pebble, on the lookout for food.

 

Burrows into the sand at nightfall, when the waters are cold, or to escape an enemy. 

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Doris "dalmatian" or leopard

Discodoris atromaculata

Family  : Molluscs

Useful facebook page  : Nudibase - sharing Nudibranch knowledge  :

https://www.facebook.com/groups/nudibase

Description  :

This white nudibranch, with a body bearing irregular brown spots, is a Gastropod Mollusk, about 12 cm long, with the appearance of a slug; it crawls on its flattened sole, on the surface of a sponge on which it feeds.

Animal sensitive to light and which is also able to detect an approach, movements in water.  

The non-segmented soft body (= Mollusc) and devoid of shell, bears towards the posterior end, in dorsal position, a naked gill (= nudibranch) in a star, around the anus, formed of 8 appendages with 3 ramifications.

 

Place of life  :

  Benthic animal found on rocky bottoms between 5 and 50 meters deep. It performs low amplitude movements: it is a sedentary species

 

Feeds on  :

He is a zoophage microphage consumer, eater of marine invertebrates that he devours while crawling on the rocks. It is a predator of sponges and in particular of the species Petrosia ficiformis or "sea fig" that it grazes with its radula (chitinous ribbon bearing many small teeth).

How to observe it while diving  :

  You can come across individuals of all sizes (a magnifying glass is useful), both in well-lit open areas and in deep caves.

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Cuttlefish or Sepia

Sepia officinalis

Family  :

mollusk, cephalopod

Description  :

It is an animal with a soft body, covered with mucus, flattened dorso-ventrally, with bilateral symmetry. The head with 2 advanced side eyes, wears a crown of 10 tentacles located around the mouth

Eight tentacles are short and have several longitudinal rows of suckers and two longer retractiles which have a tentacle club formed from 5 to 6 longitudinal rows of suckers. Just like his eyes, his brain is also evolved.

 

Place of life  :

It frequents sandy or muddy bottoms, Posidonia meadows or other marine phanerogams on the continental shelf: it is a necto-benthic species because it does not move far from the bottom, it is vagile.  Its swimming makes it free and independent of the movements of water masses (necton).

 

Feeds on  :

Motionless, hidden in the sand from which only the eyes emerge, the cuttlefish hunts on the lookout, fish and crustaceans (which it attacks by surprise): it is a voracious zoophage (carnivore) consumer, a predator (consumers of live prey).

The cuttlefish is a macrophage, that is to say an eater of large prey.  The 2 long tentacles carrying suction cups are prehensile, they are used to capture the prey from a distance. The other arms, shorter and fitted with suction cups, are used to hold the prey during the meal. Squid saliva injected into a crab or a small fish kills it: its saliva is therefore toxic

 

How to observe it while diving  :

Placed on a rocky bottom, it takes a dark hue, while on a sandy bottom its hue is light, and on a background of Posidonia, it is greenish hue.

Threatened, it flees, tentacles united and directed forwards, by a violent contraction of the walls of the cavity of the mantle, expelling a jet of water directed forward by the funnel; it causes by reaction, a jump of the animal backwards, at the same time as a cloud of black ink hides it

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To Pink Planaria

Prostheceraeus giesbrechtii

Family  :

Flatworm or Yungia

Description  :

Free, flat worm, it is the most observed planarian, mainly because of its purple / white stripes. About two centimeters in length, with bilaterally symmetrical, soft non-segmented body in the form of a thin leaf with wavy white edges.

  The head carries sense organs such as numerous ocelli (simple eyes) or chemoreceptors (sensitive to chemicals).

 

Place of life  :

Lives on the underside of stones on shallow rocky bottoms in the Mediterranean and the East Atlantic.

 

Feeds on  :

The body carries an orifice ventrally which serves as a mouth-anus communicating with a pharynx, the whole forming a suction cup (Under the order of Cotylea).

Planarians are predatory zoophagous macrophage consumers who capture worms, crustaceans, etc. which are swallowed by a ventral muscular tube (the pharynx) which devagates; enzymes are then poured onto the prey which therefore undergoes external digestion

 

How to observe it while diving  :  

In view of its small size and its place of life, it is necessary to take the time to observe well on the rocks   to see it.

 

Particularity  : They have an important power of regeneration, since starting from a fragment of their injured organism, they can be reconstituted. The 2 separate parts being each capable of giving a complete individual, in total we end up with 2 clones

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The little sea cicada

Scyllaris arctus

Family  :

shellfish

Description  :

It is an Arthropod Crustacean of reddish brown to almost black olive green color with segmented body and appendages; it can reach 16 cm long and is covered with a rectangular, chitinous shell, impregnated with limestone.

 

Place of life  :

It lives above rocky bottoms, boulder scree, between 0 and 20 meters deep, in dimly lit underwater caves, but it can also be found in the Posidonia meadow

 

Feeds on  :

It is a carnivorous macrophage consumer, predator for which chewing is external: the prey (worms, molluscs, etc.) is shredded before being ingested.

How to observe it while diving  :

She walks or crawls on the bottom; when threatened, she swims backwards, beating the water, downwards, using her swim paddle located at the end of her abdomen.

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The Coraligenous

See the article  dedicated on the Blog at this address:

https://dede789.wixsite.com/saphir-plongee/post/le-coralligène-en-3-minutes-comment-ça-marche

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