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Barfin flounder fish identification, Habitats, Fishing methods, fish characteristics
The Barfin flounder, Verasper moseri, is a rare marine fish species in the world, found in the Pacific Ocean and economically very important for aquaculture in China, Korea, Japan and Russia. This is a demersal fish that lives in cold water on sandy, muddy bottoms at depths of up to 3,000 ft (900 m). It can reach up to 28 in (70 cm) in length, and can weigh as much as 8.8 lb (4.0 kg). Barfin flounder grows rapidly at low temperatures and is a relatively high-price very valuable product. The name is associated with the surface of the eyed side body being rough like the bark of the pine.
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The Barfin flounder, Verasper moseri, is a flatfish of the family
family Pleuronectidae, also known as Matsukawa, Matsu-kawa (pine tree skin) in Japanese, Вераспер Мо з е ра in Russian. It is a large highest-priced right eye flounder, its native habitat is the northwestern Pacific: Northern Japan and south to Aomori. They distributed from the southern Sea of Okhotsk to northern Pacific coast in Japan, from the northern part Sea of Japan northward to South Hokkaido, the Korea Strait of Tartary and the Southern Kuril Islands, extended in the southwestern of Sakhalin and in Peter the Great Bay up to Yellow sea.
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Description:
The Barfin flounder has a slimy, slightly rough elongated body, depth approximately half of the length; depth of caudal peduncle is 1/4th in greatest depth of body; length of caudal peduncle, measured axially, 1 2/3rd in its depth. The eyes are on the right side of a body. Eyes small, their anterior margins opposite, the diameter of lower eye equaling distance from tip of snout to posterior nostril, 1/6th in head. Inter-orbital space is quite wide and flat, not ridge-like, its total width equaling 1/2 diameter of eyes. Head much depressed is 1/3rd in length to base of caudal fin, similar to in appearance Pacific Sand Sole (Psettichthys melanostictus), its thickness at inter-orbital space equaling distance between pupils of upper and lower eyes. It can easily distinguish from its belt-shaped body and appearance of a white spot on the eyed side. Mouth is small, very oblique, the gape strongly arched, the broad maxillary reaching a vertical behind middle of pupil, 2 4/5th in head; mandible narrowing toward tip, with very rudimentary symphyseal knob. Both jaws symmetrical, teeth obtuse, are well developed on both jaws. Teeth in upper jaw in two distinct series throughout, those of the outer series increasing slightly in size toward front of jaw, but none of them canine-like; mandible teeth in one row, except at symphysis, where a few teeth form a short outer series. Nasal openings of eyed side approximated in front of middle of inter-orbital space, the anterior with a short tube, the posterior with a raised rim.
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Gill rakers short, broad, triangular, minutely notched on inner edge, one-third diameter of eye; 7 present on horizontal limb of outer arch. Lateral line with a short high anterior arch, the string of which is 1/5th the straight portion. The height of the arch is one-third its length. Behind the arch, the lateral line descends in a gentle curve to middle of sides. Dorsal fins start above front of pupil, the rays rising in length to the 45, which is 2 2/7th in head. Longest anal ray (the 17th) is 2 1/7th in head. Tail broadly rounded, 1 2/5th in head. Pectoral fins short and broad, 2 2/5th in head. Ventrals of almost equal length, reaching origin of anal, 3 1/5th in head. No anal spine.
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The scales are very rough, lengthwise; smoothly when touch, each possessing several long, sharp spines diverging from median portion of posterior margin. Anterior and posterior portions of dorsal and anal fins naked, the rays of the middle portion each with a series of strongly ctenoid scales. Caudal densely scaled to tip. Pectorals and ventrals are naked, not covered with any scales. Head covered with strongly spinous scales, except for snout, maxillary, and mandible. On blind side the scales are rough on head, ventral area, and along bases of ventral fins; largely smooth elsewhere. The snout, jaws, pre-operculum, sub-operculum, lower half of gill cover, and all but a central strip on inter-operculum are scaleless on blind side of head.
Key characters
Vertical fins are with streaks following the rays from base to tips; arch of lateral line very abrupt and high. Mouth is small; upper premaxillary teeth in 2 series, teeth uniformly small, without canines.
76-86 Dorsal fin rays
53-63 Anal fin rays
12 Pectoral fin rays
37-41 Vertebrae
84-100 scales in lateral line
Max length: 70.0 cm
Max. Weight: 4.0 kg
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The color of the eyed side of the body is tinged yellow-like to brown with slightly reddish, blind side is light-white or is yellow. A color is different from size in male and female. Centers of the scales light gray, the margins dark brown. Fins light or dusky, the vertical fins with obvious dark transverse strips parallel with the rays. These are most evident on the under side, where the pigment seems to principally occur, and are seen through the fin more faintly on the colored side. Dark strips are located also on the tailed fin. A dorsal fin and an anal fin have a clear black spot. Lining of cheeks and gill cover of colored side are dusky. Peritoneum is gray.
The Barfin flounder is closely related to
Spotted Halibut, Verasper variegatus, of the same genus. Main different in the much lower and smaller arch of the lateral line in Spotted Halibut than in Barfin flounder. The fins in Spotted Halibut are spotted with black, but not barred. It is similar to Spotted Halibut however you can recognize it easily because of the belt-shaped pattern of its fins and the white spots on its body. The body size is different depending on the sex.
Habitats:
The Barfin flounder lives in the demersal, marine, costal waters, but does not avoid the freshened waters in the mouths of rivers. It dwells mainly at the depths from 1 to 200 m, however, it can move down to 900 m depth environment. It inhabits the sand mud bottom and eats fish, lobster brachyuran, large crustacean or a lugworm and other animals. Spawning flows in the winter-spring period.
Spawning:
Females became maturity at age 3 and length 45cm and males at 2 years old and 34cm; however the age at first maturity varies with body size. Barfin flounder spawn in costal waters in Hokkaido, Japan from April to June, under water temperature of 6 �C, usually at night time from 10p.m. to 4a.m. The female spawn repeatedly for approximately one month ones a year. One female can spawn 10 - 11 times for one spawning season with average spawning intervals from 2.9 to 3.5 days. The start of spawning and the spawning period could be different. Female can reproduce averaged between 85,000 to 406,000 pelagic eggs during a spawning season. Female (approx. 72 cm in length) could produce up to 180 thousands of eggs at one time.
The fertilized eggs average diameter 1.77�0.02mm is global, which have transparent yolk and homogeneous but with no oil ball. In the middle spawning period, the proportion of fertilized eggs was higher than that in the early or last spawning season. Egg diameters became smaller with the increase of spawning time. Juvenile pigments appear when olfactory plates begin to form. Hatching takes place on the 8th to 10th day after fertilization at a water temperature of 8�C, and the hatched larvae absorb almost all of their yolk-sac masses within 21 days after fertilization. The newly hatched larvae with average total length of 4.69�0.15mm are transparent, floating on the water surface. During the 5th day after hatching the body surface of larvae appear more melanophores, pectoral fins begin to develop, which enable larvae to swim horizontally. On the 25th day, the larvae�s notochord bends upwards, the fin rays of odd fins differentiate, some pigment cells on the fin rays of dorsal fin and anal fin concentrate, and mastoid teeth on mandible appear. On the 30th day, left eye of larvae begin to move upwards. On the 51st day, the left eye moves to the right and larva metamorphosis is accomplished. Barfin flounder females grow faster than males.
Fishing Methods:
The Barfin flounder is fished mainly in Iwate by a gill net. It is a delicious high-quality fish, one of the best fish of the sashimi with a high price, great grilling fish with the good quality fat. The male is considered tastier than the female and so it is ranked at a higher level. Very few are caught. Efforts have been made to stock certain areas in recent years. Along with Spotted Halibut, Verasper variegatus, it is a high ranking fish next only to
Summer flounder.
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