Melicertus Kerathurus

– Caramote Prawn –

Description

This shrimp is large in size : the total length, from the tip of the rostrum * to the tip of the suchon * is at most, in males, 18 cm (usually 11 to 14 cm) and in females 22.5 cm (usually 13 to 17 cm).
The general color of the animal is beige. On the side, the dark bands form separate spots.
The tip of the caudal fan is sky blue , edged with red bristles.
The appendages are rather yellow. The first three pairs of walking legs are terminated by a small clamp .
The suchon is pointed and provided with three movable spines on each side.
Laterally, the first abdominal segment covers the second.
The rostrum is short and barely protrudes from the eyes; it has eight to thirteen dorsal teeth and a single ventral one.

Certain details of carapace ornamentation, observable especially in the laboratory, are widely used systematically:
Behind the last dorsal tooth, there is a double carina with a deep and typical median groove extending to the posterior edge of The carapace ; a long ridge runs parallel to the rostrum.
On the hepatic region there is a ridge in antero-ventral direction; the gastro-frontal ridge is present. The abdomen has a dorsal carina on all segments, and ends with a spine on the sixth segment.

Similar Species

In Europe, caramot can be confused with the Japanese shrimp Marsupenaeus japonicus . In the latter the dark bands are continuous transversely on the first four abdominal segments, which is not the case in the caramot.

Biotope

The caramot Melicertus kerathurus is a demersal species *, living in coastal regions or in brackish waters *, on sandy or sandy-muddy bottoms, generally at depths of 0.5 to 90 m, most often between 5 and 40 m.

Exceptionally, the species has been recorded at depths varying between 100 and 640 m in the Strait of Sicily.

Alimentation

The caramot is an active predator with low selectivity for its prey. She has a diversified diet, and mainly consumes molluscs, crustaceans and polychaetes.

Reproduction

Some studies suggest that this species changes sex during its life. She would therefore be a * protandric * hermaphrodite (first male the first year and then female), but this is not really proven. A high percentage of females mature from May to July in the Aegean Sea. It is recognized that the female is mature by observing the ovary which is swollen and colored greenish-beige and is visible dorsally by transparency in the animal. The older females lay earlier than the younger ones.

Spawning in the Mediterranean takes place depending on the local temperature between May and November; it is carried out at night in open water. The number of eggs laid varies between 100,000 and 800,000 depending on the size of the females.

The larvae pass through the nauplius *, zoé * and mysis * stages before metamorphosing into juveniles. The larvae are planktonic, and stay close to the coast until they reach the first post-larval instar; they then abandon their planktonic life and become benthic, living in the littoral zone.

The service life is 2 to 3 years.

Associated Life

In the same coastal areas as the caramot, we typically find several other crustaceans: the prawns Palaemon spp. ( P. adspersus, P. serratus , P. elegans), the gray shrimp Crangon crangon , the penaeid Metapenaeus monoceros (for example in the Gulf of Gabès), and the Mediterranean green crab Carcinus aestuarii . It is not a true interspecific association but a biocenosis * (community of species frequenting the same environment).

Various Biology

The caramot makes movements related to reproduction. Juveniles move to relatively warm, low salinity waters rich in plankton where they can grow rapidly. Then they leave the coastal lagoons to go to the sea where they finish their growth and reproduce.

Behaviorally, this species presents two very distinct phases of activity. By day, the animals are motionless, buried in the sediment and in a low metabolic state (they “sleep”). At night, the animals are active.

Further Information

Caramot, an edible species, is traditionally fished along the Atlantic and Mediterranean coasts. It is regularly present on the markets of Spain, Morocco, Tunisia and Italy. Due to its high commercial value, it has a certain economic importance. Caramot aquaculture was somewhat developed in the 1980s; the aggregate production of Penaeus kerathurus reached 7,700 tonnes in 2000 and 6,655 tonnes in 2005.

In the Mediterranean, populations of the caramot Penaeus kerathurus are declining due to the invasion of penaeid species originating from the Red Sea such as Marsupenaeus japonicus and Metapenaeus monoceros in Tunisia. Caramot has almost disappeared along the entire eastern Mediterranean coast, in southern Turkey and as far as the Aegean Sea. The management and protection of this species is quite difficult in the face of this type of threat.

Threats

The Lessepsian migration of Erythrian penaeid prawns through the Suez Canal into the Mediterranean may lead to increased competition for Melicertus kerathurus and the invasive Metapenaeus monoceros has already been implicated as a causal factor in the local extinction of M. kerathensis in the south-eastern Mediterranean.^[7] M. monoceros is now the most important target species for commercial, inshore, fisheries in the Gulf of Gabes, Tunisia, and off Egyptian Mediterranean coasts. In coastal lagoons the invasive prawns Penaeus pulchricaudatus and Penaeus semisulcatus make up a major portion of the prawn catch. In addition the northern brown shrimp Farfantepenaeus aztecus has now been found in the Mediterranean and may be another source of competition for M. kerathensis, as well as being a potential vector for the bopyrid parasite Epipenaeon ingens ingens.^[8]