Sphyraena Viridensis

– Yellowmouth Barracuda –

Sphyraena viridensis, the yellowmouth barracuda or yellow barracuda is a predatory ray finned fish from the family Sphyraenidae, the barracudas, which is found in the warmer waters of the western Atlantic Ocean and the Mediterranean Sea. It is often confused with the European barracuda Sphyraena sphyraena.

Description

Sphyraena viridensis has a long, fusiform body with a long, streamlined pointed snout which has a long mouth lined with two rows of sharp, fang-like teeth and a jutting lower jaw. There are no scales on the preoperculum, unlike S. sphyraena which has scales on both the anterior and posterior margins of the preoperculum. There are numerous transverse dark bars on the dorsum and these are longer,extending below the lateral line, towards the head while in S. sphyraena they do not extend to the lateral line.^[3] 

Generally the colouration is a countershaded dark above, silvery below and the barring fades on dead specimens.^[4] Juveniles are described as being dark yellow or greenish in colour.^[5] S. viridensis averages smaller than S. sphyraena growing to a standard length of 65 cm, although the average length is 35–40 cm.^[4] but specimens up to 114.5 cm have been caught of the Azores.^[5] The rod caught record is 10.2 kg which was caught off Lanzarote in the Canary Islands in 2007.^[6]

This fish has a general hydrodynamic appearance.
The body, fusiform, silvery gray, has a lighter belly; the sides are striped with dark bands widening below the lateral line *.
The two dorsal fins, short , are slightly yellowish and the caudal, very indented, is bordered of black .
The first dorsal is very set back from the pectoral fin.
The thin head has a prominent, pointed lower jaw . The upper jaw has a low protractile capacity *. The generous dentition, in two rows, is turned inwards.
The cheeks are without scales at the level of the preoperculum *.
The eye is round.
This species can grow up to 120 cm long.

Distribution

The exact distribution of Sphyraena viridensis is unclear because of confusion with S. sphyraena. It occurs in the eastern central Atlantic around the Azores, Madeira, Cape Verde Islands and the Canary Islands and has been recorded in the eastern Mediterranean off Lebanon.^[2] It has also been recorded in the Mediterranean in the Adriatic Sea, Aegean Sea, off Israel, Algeria, Corsica and Sicily.^[3][5]

Biotope

The species frequents two biotopes *, depending on age:
– Juveniles prefer shallow areas. They hide readily in the semi-darkness of the rocks (port areas) on the fringes of Posidonia meadows in order to pounce on potential prey. They also escape the teeth of their elders in these places. Their shape evokes a plant floating with the current (torn posidonia leaf).
– Adult, pelagic * specimens are nevertheless fond of drop-offs, dry areas or coastal areas, in summer as in early autumn. They are found in water deeper than ten meters, which does not prevent them from crossing in open water, between 3 and 5 m. They can meet up to 110 m.

Similar species

Sphyraena sphyraena (sea pike): is distinguished from S. viridensis by barely or not visible black bands and the presence of scales on the preoperculum, a gray-brown to gray-blue back and silvery white sides. Dark bars are frequently lacking or are very faint. Serious
confusion possible with Sphyraena viridensis .

Sphyraena chrysotaenia (yellow- lined beak): Lessepsian species from 30 to 40 cm, present in the eastern basin of the Mediterranean; is distinguished by yellowish-brown horizontal lines, sometimes not very marked, and a yellow caudal.

Alimentation

Fish, molluscs, cephalopods, crustaceans are on the menu of this hunter. In the Azores, analysis of stomach contents revealed that 66% of the remains observed consist only of fish. In this area, the yellow-mouthed barracuda feeds mainly on juveniles of horse mackerel Trachurus picturatus , observed in 82.2% of full stomachs.

Reproduction

Really little information available about this species but scientific work has shown that it has a very low turnover rate. A video taken in Spain by amateur divers shows behavior that may be linked to reproduction: a small group of yellowmouth barracudas swims without a determined direction, very quickly, without paying attention to the divers, and some individuals seem to want to rubbing against others “. Any other observation, especially if it is accompanied by pictures, will be welcome!

Various Biology

Different types of aggregations were observed: small groups and individuals isolated in winter, large schools in summer and autumn responding to different feeding and predatory strategies.
The yellow-billed becune is capable of sharp accelerations, it has a powerful tail; its top speed is around 44 km / hour.
This southern species is more and more regularly observed in schools by divers, on the French Mediterranean coasts.

Ecology

In the Azores fish made up all of the diet and the most important species in the diet of Sphyraena viridensis was the bluejack mackerel Trachurus picturatus being found as having been preyed upon by 72.4% of the fish sampled and making up nearly two thirds of the weight of prey taken. Other species taken in this study included single examples of bogue Boops boops, ornate wrasse Thalassoma pavo and axillary sea bream Pagellus acarnae, as well as an unidentified species of the Exocoetidae. Unidentified fish remains were found in nearly 20% of the specimens sampled. In the same study the predatory behaviour of S.viridensis was observed and they are active pursuit predators of fish with one or many barracudas pursuing fish, either singling out lone prey or attacking shoals of prey fish. The pursuit was rapid and was usually over in 8–40 seconds and the more fish were involved the higher the rate of success was. In these observations other fish species than those sampled from specimens were observed as prey e.g. longspine snipefish Macrorhamphosus scolopax and boar fish Capros aper.^[5] It is also known to feed on cephalopods and crustaceans.^[4]

In summer they form schools of up to 180 fish, although most schools number 30-40 fish, in areas where there are strong currents. These schools are predominantly made up of sub-adult fish with the smaller fish nearer to the surface and the larger, usually female, fish at the bottom of the school at depths of up to 30m. In winter the only aggregations are small groups of juveniles in shallow bays. No territorial behaviour was observed. Schooling is thought to be an anti predator defence and to facilitate mating with the smaller males being attracted to the larger females, in addition groups of barracudas were more successful in hunting prey fish than single fish. This species does not appear to mix with other barracuda species in mixed schools but there are reports of these fish associating with whale sharks in the Azores and an instance of them actively swimming towards a manta ray Mobula tarapacana.^[5]

In the Azores juveniles of Sphyraena viridensis are preyed upon by the lizard fish Synodus saurus, this predation shows that there is an overlap in habitat between the juvenile barracudas and the lizard fish which occur in sheltered, very enclosed bays with sandy substrates.^[7]

Fisheries

Sphyraena viridensis is landed in small quantities in the eastern Mediterranean by fishermen using in trammel-nets and beach-seines.^[4] It has been reported from markets in Turkey but it is generally caught as a bycatch, although as numbers increase in the Mediterranean it may be becoming a more important species for fisheries.^[1]