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Fine Flounder fish identification, Habitats, Fishing methods, fish characteristics
The Fine flounder (Paralichthys adspersus), is a species of large-tooth left-eyed flounders, family Paralichthyidae, Genus Paralichthys. It is a medium sized flatfish, growing up to 70 cm in length, with females typically being larger than males. Fine flounder is a game fish, caught by an artisanal fishery off the Peruvian coast.
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The Fine flounder (Paralichthys adspersus), also known as Chilean flounder, Hunboruto-hirame (Japanese), Lenguado, Lenguado fino (Castilian), is a species of large-tooth flounder native to the eastern Pacific Ocean, along the continental shelf from the coast of Ecuador in the north to the coast of Peru in the south.
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Description:
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The Fine flounder has high, moderately elongate and compressed body; body height is about 45% of a standard length. Head is big, its length is approximately 30% of standard length and has the almost straight profile; I nuzzle a little bigger than the diameter of the eye. Eyes are small, shorter than snout, the size of 1/6th of a head length, are on the left side, separated by a flat space without a ridge. Large, long and oblique mouth is 44% of head length. Mouth ends under rear of eye, the later margin of the top jaw reaches the later margin of the top eye that is more anticipated than the low eye. Teeth are large, sharp, and slightly recurved, larger in front of jaws. Snout is very slightly produced; inter-orbital is moderately wide, its posterior covered half with the scales; anterior nostril with a flap which reaches to middle of posterior nostril.
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Dorsal fin begins over an upper eye; back elongated fin originates at level of the half of the eye in the adult species. Bases of the pelvic fin rays are symmetric sub-equal. There is urinary papilla on the eyed side, immediately behind level of an anus. Pectoral short fins in the eyed side ends almost to the half of the length of the head, slightly reaching past curve of lateral line, its tip pointed and on the blind side pectoral short fins ends almost a third of the length of the head, not reaching to end of curve, its tip blunt. Gill rakers are hardly as long as eye.
The eyed side is covered with ctenoide rough scales, large fish with small accessory scales between larger body scales and blind side scales are cicloides, smooth. Side line strongly curled in his initial portion, it is continued almost in straight line towards the later region. Lateral line is extending onto head, with branches to upper eye and below lower eye, strongly arched over pectoral fin. Snout and mandible are naked; end of maxillary and rest of head are covered with scales; the rays of all the fins are covered with small scales; the membrane is naked; each scale on body with a row of accessory scales around its posterior edge; scales cycloid, the accessory scales giving the fish a rough feeling; origin of dorsal over anterior edge of upper eye, bending slightly toward the blind side; caudal double lunate.
Key characters
Pectoral fins short, about half of head on ocular side and about one-third of head on blind side.
65-77 Dorsal fin soft rays
54-65 Anal fin rays
21-26 Gill rakers (3 to 6 + 15 to 17)
95-112 Lateral line scales
Caudal fin double truncate
Maximum size: 70cm.
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The eyed side is brown to grey, with or without pale and many larger and smaller dark spots and blotches, fins lighter than body, unpaired ones marked like body, pectoral and pelvic with small dark spots, often in rows on pectoral.
Habitats:
Adults of this species inhabit soft substrata on the continental shelf, whereas juveniles occur in shallower waters including estuaries and mangrove habitats. It feeds on mobile invertebrates and fishes. This species is found at depths to 35 m. Baby Fine flounder begin feeding as an ambush predator as soon as they settle on the bottom. The juvenile fish are normally in very shallow estuarine areas and feed on tiny shrimp like copepods, small crabs, a variety of sea worms and invertebrates. The species is a predator, feeding off smaller fishes in its habitat.
Spawning:
Fine Flounder spawn year around. Both males and females become sexually mature at the age of 3 to 4. Females typically release several hundred thousand eggs. The fecundity (number of eggs produced in a single spawning season) of females increases with size and weight. Fine Flounder hatch offshore. The eggs float in the water column, hatching 60 hours after fertilization.
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Larvae are 1.7mm; yolksac is more than half the body length; a small oil globule (0.13mm) is present posterior to the yolksac. Eyes of yolksac larvae are not pigmented. Few, relatively-large melanophores are found near the tip of the notochord on the head, trunk, and yolksac except at the ventral margin.
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Pigment forms on the medial region of the pelvic fin, the eyes start to pigment. With absorption of the yolk, the yolksac larva becomes slender; the gut, jaws, and pectoral fins develop; and two sphenotic spines begin to develop on each side of the head, initially the upper one is the larger. 4-5 days after hatching at length 3.5mm, the yolk is exhausted, the mouth is functional, eyes are pigmented, and the pectoral fin is formed, a series of melanophores forms on each side, slightly dorsal to the midline.
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The most important distinguishing features of preflexion larvae are the presence of 2 sphenotic spines and absent of pigmentation in the dorsal finfold. Body depth is moderate (13.9%) and pre-anal distance is 41.4%, stellate melanophores are present on the head and over the anterior 2/3 of the body. Head pigmentation consists of melanophores over jaws, preopercle, opercle, and dorsal and lateral brain region. At 4.5mm, preopercular and opercular spines appear. Opercular spines are located at the upper portion of the bone and are more prominent than preopercular spines. At 6.5mm, the elongated 3 rays of the dorsal-fin crest begin to appear.
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The flexion stage is characterized by an increase in body depth (22.8% of a length) and development of the caudal fin. Preopercular spines are in 2 series in the upper and lower margins of the bone. Opercular spines are in 2 groups: an upper group on the body of the operculum and a lower group along its margin. Elongated dorsal-fin rays remain with the middle one the longest. The presence of 2 groups of numerous opercular and preopercular spines, as well as 2-3 elongated dorsal-fin rays, is diagnostic characteristics of flexion larvae.
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At 7.5mm, the pelvic fins begin to form and dorsal, anal and caudal fin rays are became more evident, reaching their full complements at 8.8mm. At 8.1-8.6mm the hypural complex develops; the anal-fin pterygiophores appear in advance of their corresponding fin rays. In both fins, development proceeds posteriad. The pelvic fin appears at 8.5mm, and all six rays are present at 10.1mm standard length. There are 18 caudal-fin rays, plus 2 procurrent rays.
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At the flexion stage pigment intensifies in the tail region, head and interradial membrane of the elongated dorsal-fin rays. The dorsal fin is pigmented, particularly in the posterior half, and the ventral region of the abdomen becomes pigmented. Tail melanophores concentrate in the ventrolateral region, while the paired series dorsal to the notochord is became evident. Dorsal crest fin rays increase in relative length; the second reaches its maximum length (53% of standard length). The short dorsal-fin ray anterior to the crest begins to develop. The interocular region begins to change in preparation for eye migration.
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During metamorphosis pigmentation increases on the left side of the body. Dorsal fin pigmentation is concentrated in the posterior half of the fin. Groups of melanophores are present on the interradial membrane of the anal fin. The pelvic fin is almost completely pigmented. The second dorsal fin is being reabsorbed. Migration of the right eye to the left side begins and completed at 13.0mm. Pectoral-fin rays form. Preopercular and opercular spines are lost, as are the elongated dorsal fin rays. There are 33 (4-6 pre-anal and 27-29 post-anal) myomeres at the end of the stage.
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Fishing Methods:
The Fine flounder is a good game fish, caught by an artisanal fishery off the Peruvian coast.
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