Preanal Length Research Articles

우리나라 남해에 분포하는 붕장어(Conger myriaster)의 연령과 성장

【Age and growth of whitespotted conger Conger myriaster were estimated using right sagittal otoliths from 495 fish collected from February, 2004, to January, 2005, in the southern coastal waters of Korea. Examination of the outer margin of the otoliths showed that opaque zones formed once a year and annual rings formed from April to June. The ages of the specimens examined ranged from 3 to 8 years. Whitespotted conger spawn from December to March. Allometry between preanal length and total weight can be expressed as $TW=0.0350{\times}PL^{2.9173}$ ( $R^2=0.89$ ). There was no significant difference in allometry between females and males (P>0.05). The estimated VBF growth equation was $L_t=415.2(1-e^{-0.1457(t+0.4654)})$ .】

Gymnothorax melanosomatus, a new moray eel (Teleostei: Anguilliformes: Muraenidae) from southeastern Taiwan

Gymnothorax melanosomatus new species, is described here on the basis of eight specimens collected from eastern coastal Taiwan at a depth 50–180 m. This new moray eel is distinguished from a closely similar species, G. prolatus, by a combination of the following characters: a uniformly black body when fresh (vs. brown), a relatively long preanal length 58.5 % of TL (vs. 48.9), shorter snout length 17.8 % of HL (vs. 20.0), interobital width 12.2 % of HL (vs. 14.3); more preanal vertebrae 105–109 (vs. 74–86) and total vertebrae 201–211 (vs. 174–190). The male and female are not different in body color and pattern, but the numbers of median intermaxillary teeth are different between the sexes, 0 in male and 2–3 in female.

Gymnothorax melanosomatus, a new moray eel (Teleostei: Anguilliformes: Muraenidae) from southeastern Taiwan

Gymnothorax melanosomatus new species, is described here on the basis of eight specimens collected from eastern coastal Taiwan at a depth 50–180 m. This new moray eel is distinguished from a closely similar species, G. prolatus, by a combination of the following characters: a uniformly black body when fresh (vs. brown), a relatively long preanal length 58.5 % of TL (vs. 48.9), shorter snout length 17.8 % of HL (vs. 20.0), interobital width 12.2 % of HL (vs. 14.3); more preanal vertebrae 105–109 (vs. 74–86) and total vertebrae 201–211 (vs. 174–190). The male and female are not different in body color and pattern, but the numbers of median intermaxillary teeth are different between the sexes, 0 in male and 2–3 in female.

Effects of Precaudal Elongation on Visceral Topography in a Basal Clade of Ray‐Finned Fishes

Elongate body forms have evolved numerous times independently within Vertebrata. Such body forms have evolved in large part via changes to the vertebral column, either through addition or lengthening of vertebrae. Previous studies have shown that body elongation in fishes has evolved most frequently through the addition of caudal vertebrae. In contrast, however, body elongation in Polypteriformes, a basal clade of ray-finned fishes (Actinopterygii), has evolved through the addition of precaudal vertebrae; one genus, Erpetoichthys, has approximately twice as many precaudal vertebrae as do members of its sister genus, Polypterus. Thus, polypteriform fishes provide an excellent opportunity to study the effects of precaudal elongation on the gross morphology and organization of visceral organs contained within the body cavity. In this study, we document the anteroposterior positions of most major visceral organs in representative species of both genera (E. calabaricus and P. palmas), relative to both vertebral number and percent pre-anal length. We found that, whereas the positions of the anterior and posterior borders of the visceral organs relative to percent pre-anal length were generally similar between the two species, most visceral organs were positioned further posteriorly in E. calabaricus than in P. palmas with respect to vertebral number. Based on previous determinations of the molecular control of anteroposterior patterning of the visceral organs, we discuss which possible changes in gene expression may have led to the anatomical modifications seen in the visceral morphology of Erpetoichthys.

Larval development and shape variation of the kelpfish <em>Myxodes viridis</em> (Teleostei: Clinidae)

Larval development and shape ontogeny of the kelpfish Myxodes viridis (Clinidae) are described for the first time. A total of 214 individuals ranging between 3.51 and 23.09 mm standard length collected off central Chile were assessed employing classic and geometric morphometrics, illustration with camera lucida and a double-staining technique for cartilaginous and bone structure observation. Based on characteristics such as yolk sac presence and fin formation, six stages of larval development were differentiated: yolk sac, preflexion, flexion, early postflexion, late postflexion and juvenile. Shape changes during development are subtle and occur smoothly, being more significant in the head and preanal length, and ontogenetic allometry accounts for almost 15%. Cartilage formation takes place first at the branchial arches and cranium; then hypural, haemal and neural arches are consecutively formed. Bony structure ossification occurs late in the development. Vertebral centra ossify directly, without cartilaginous matrix replacement.

Age, growth and reproduction of cutlassfishes Trichiurus spp. in the southern East China Sea

Summary The cutlassfish is one of the most commercially important continental fishes in the East China Sea. However, the current classification of cutlassfishes is suboptimal and complicates fisheries management. This study investigated the growth and reproduction of three cutlassfish species in the southern East China Sea. Between August 2002 and September 2003, a total of 2717 specimens of Trichiurus japonicus, T. sp.2 (likely synonymous for T. nanhaiensis) and T. lepturus were collected monthly from Daxi, Anping, Nanfangao, Donggang and Xingang fishing ports. The von Bertalanffy growth model in preanal length (PL) resulted in PL (mm) for T. japonicus, PL(mm) for T. sp.2 and PL (mm) for T. lepturus. Their growths were significantly different between sexes for T. japonicus and T. sp.2 and among the three species. From macroscopic examination of ovaries, histological inspection of oocytes, and analyses of gonosomatic and hepatosomatic indices, T. japonicus was likely to spawn all year round, with two peaks in February–July and November–December. T. sp.2 spawned relatively later, between April and August. The length at sexual maturity of T. japonicus females was 264 mm PL or 746 mm total length. The sex ratios of T. japonicus and T. sp.2 were significantly different from 1 : 1 whereas T. lepturus showed no significant difference. The three species of trichiurids have different geographical distributions in this region.

Unraveling a 146 Years Old Taxonomic Puzzle: Validation of Malabar Snakehead, Species-Status and Its Relevance for Channid Systematics and Evolution

BackgroundThe Malabar snakehead Channa diplogramma is one of the most enigmatic and least understood species within the family Channidae, which comprise one of the most important groups of freshwater food fish in tropical Asia. Since its description from peninsular India in 1865, it has remained a taxonomic puzzle with many researchers questioning its validity, based on its striking similarity with the South East Asian C. micropeltes. In this study, we assessed the identity of the Malabar snakehead, C. diplogramma, using morphological and molecular genetic analyses, and also evaluated its phylogenetic relationships and evolutionary biogeography.Methodology/Principal FindingsThe morphometric and meristic analysis provided conclusive evidence to separate C. diplogramma and C. micropeltes as two distinct species. Number of caudal fin rays, lateral line scales, scales below lateral line; total vertebrae, pre-anal length and body depth were the most prominent characters that can be used to differentiate both the species. Channa diplogramma also shows several ontogenic color phases during its life history, which is shared with C. micropeltes. Finally, the genetic distance between both species for the partial mitochondrial 16S rRNA and COI sequences is also well above the intra-specific genetic distances of any other channid species compared in this study.Conclusions/SignificanceThe current distribution of C. diplogramma and C. micropeltes is best explained by vicariance. The significant variation in the key taxonomic characters and the results of the molecular marker analysis points towards an allopatric speciation event or vicariant divergence from a common ancestor, which molecular data suggests to have occurred as early as 21.76 million years ago. The resurrection of C. diplogramma from the synonymy of C. micropeltes has hence been confirmed 146 years after its initial description and 134 years after it was synonymised, establishing it is an endemic species of peninsular India and prioritizing its conservation value.

Biometric characteristics of small Atlantic bluefin tuna (Thunnus thynnus, Linnaeus, 1758) of Mediterranean Sea origin

The aim of this study was to provide a detailed description of the biometry of the juvenile Atlantic bluefin tuna (FL = 50–127 cm) of Mediterranean Sea origin. Regarding meristic features, there were 31.5 (SD = 2.1) gillrakers found on the first gill arch, 13.41 (SD = 0.494) spines in the first dorsal fin, 33.56 (SD = 2.124) soft rays in the pectoral fin, 9.86 (SD = 0.464) dorsal finlets and 8.90 (SD = 0.412) ventral finlets on the tail. Results of morphology analyses indicate that, on average, the head length contributes 28.84% (SD = 0.745); first predorsal length contributes 31.86% (SD = 0.915); preanal length contributes 61.45% (SD = 1.632); maximum body height contributes 26.90% (SD = 1.001); second dorsal fin height contributes 11.11% (SD = 1.457); pectoral fin length contributes 20.09% (SD = 1.550); and caudal fin width contributes 28.60% (SD = 1.842) of the fork length. Eye diameter comprises 13.14% (SD = 1.471), snout length 33.11% (SD = 1.332) and postorbital length 53.75% (SD = 1.354) of the head length. The significant change in body proportions, as fish grow in length, has been noted and leads to the conclusion that the juvenile bluefin body does not grow isometrically in size. Continuous decrease in the mean condition factors as body length increased, and a length–weight relationship describing negative allometric growth [ln WW (g) = −3.2965 + 2.8546 ln FL (cm)], indicate elongation of the juvenile bluefin body shape during early life, corresponding mostly to the period preceding sexual maturity.

Morphometric differences among populations of Tu’ini, Capoeta damascina (Teleostei: Cyprinidae), in the interior basins of Iran

Summary Tu’ini, Capoeta damascina, is a widespread species in the interior basins of Iran. To examine the morphometric variations residing within the taxon, six isolated river systems from the west, south, southwest, and centre of Iran were investigated: Gharasu, Hanna, Bazoft, Eghlid, Abadeh, and Gamasiyab. A total of 240 adult fish specimens ≥180 mm standard length (females: 180–336; males: 186–304) were collected from March to June 2008. Based on the multivariate methods used (factor analysis, canonical variates analysis, and a classificatory discriminant analysis), the river samples were clearly separated into distinct groups. The Gharasu River sample was separated into a distinct group by differences in inter-nasal distance (iND), inter-orbital distance (iOD), and barbel length; the Hanna by iND, iOD, body depth (BD), minimum BD, caudal peduncle (CP) depth, CP width, and pectoral-anal distance; the Bazoft by head depth, iND, CP length, and preanal length; the Eghlid by anal-caudal distance; the Abadeh by postorbital length; and the Gamasiyab River by preorbital length, dorsal fin height and base, eye diameter, BD, preventral length, and pectoral-ventral distance.

A new catfish, Hara koladynensis from northeastern India (Siluriformes: Erethistidae)

A new Erethistid catfish species, Hara koladynensis is described from Koladyne River, Mizoram, India. It is distinguished from its congeners in having rough (vs. smooth or serrated) anterior margin of dorsal spine; shorter pre-anal length (58.5-60.9% SL vs. 63.2-75.2), longer head (36.0-38.3% SL vs. 24.8-34.2%), longer post-adipose distance (18.6-21.9% SL vs. 12.3-18.3), and deeper body (21.9-25.2% SL vs. 11.5-20.9).

Growth and morphological development of laboratory-reared larval and juvenile snakeskin gourami Trichogaster pectoralis

Morphological development, including that of fins, labyrinth organ, body proportions, and pigmentation, in laboratory-hatched larval and juvenile snakeskin gourami Trichogaster pectoralis is described. Body lengths (BL; mean ± SD) of larvae and juveniles were 2.3 ± 0.1 mm just after hatching (day 0) and 8.2 ± 0.6 mm on day 22, reaching 14.1 ± 2.3 mm on day 48. Aggregate fin ray numbers attained their full complements in juveniles >11.8 mm BL. Preflexion larvae started feeding on day 2 following upper and lower jaw formation, the yolk being completely absorbed by day 12. Subsequently, oblong conical teeth appeared in postflexion larvae >8.2 mm BL (day 16). Melanophores on the body increased with growth, with a large dark spot developing on the lateral midline at the caudal margin of the body in flexion larvae >6.1 mm BL. Subsequently, a broad vertical dark band from the eye to the caudal peduncle developed in postflexion larvae >8.9 mm BL. Proportions of head and pre-anal lengths became constant in postflexion larvae greater than ca. 9–10 mm BL, whereas those of maximum body depth, eye diameter, and snout length failed to stabilize in fish of the size examined in this study. First soft fin ray of the pelvic fin elongated, reaching over 40% BL. The labyrinth organ differentiated in postflexion larvae >7.4 mm BL (day 22). Comparisons of larval and juvenile morphology with another anabantoid species Anabas testudineus were also made, revealing several distinct differences, particularly in the numbers of myomeres and fin rays in the dorsal/anal fins, mouth location and body shape.

A new species of freshwater eel Anguilla luzonensis (Teleostei: Anguillidae) from Luzon Island of the Philippines

Anguilla luzonensis, a new species of freshwater eel, family Anguillidae, is described on the basis of 29 specimens collected from the Pinacanauan River system, which is a tributary of the Cagayan River on northern Luzon Island of the Philippines. The new species and A. celebesensis, which is distributed in the same region, both have variegated color marking and broad maxillary bands of teeth, but show statistically significant differences in the following characters of the new species: predorsal-fin length 28.6–33.1% of total length (TL); preanal length 39.6–44.8% of TL; trunk length 26.4–31.3% of TL; distance between the verticals through the anus and origin of the dorsal fin 9.3–13.9% of TL; length of gape 35.5–46.9% of head length; the total number of vertebrae 103–107; and number of abdominal vertebrae 40–42. These morphological differences, together with the present knowledge about anguillid eel taxonomy, genetics, and ecology, strongly support the presence of the new species A. luzonensis in the area of northern Luzon Island of the Philippines.

성숙 유도한 한국산 고등어 (Scomber japonicus)의 난발생과 자치어의 형태 발달

Development of egg, larvae and juveniles for the Pacific mackerel, Scomber japonicus are described following natural fertilization in the indoor tank of <TEX>$25^{\circ}C$</TEX> water temperature. Following a routine hormone treatment technique for the brood stock, male and female mackerels were artificially matured by intramuscular injections of LHRHa at a dosage of <TEX>$400{\mu}g/kg$</TEX> body weight (BW)+Domperidone at a dosage of <TEX>$4{\mu}g/kg$</TEX> body weight (BW) to induce maturation in a separate aquarium and induced natural spawning. Fertilized eggs were ca. 1.0 mm in diameter; spherical in shape with a single oil globule; pelagic and non-adhesive. Hatching occurs 41 hours after fertilization at <TEX>$23-24^{\circ}C$</TEX>. The newly hatched larvae was 3.03 mm in average total length (ATL), the mouth and anus were not open, oil globule located in posterior end of yolk sac, and preanal length was 42.8% of TL. The larvae measuring 2.89 mm ATL, almost absorbed yolk sac and oil globule material in 2 days after hatching, in which the mouth and anus were open. Melanophores, branch or star in shape were observed on the top of head, peritoneal region and along the ventral contour. In 13 days after hatching, the larvae was 6.88 mm ATL, its posterior end of notochord began to flex upward, finfold of caudal fin appeared, jaw teeth were already formed. In 19 days after hatching, the larvae was 7.71 mm ATL completed only caudal fin rays (9+8), and preanal length was 49.4% of TL. In 37 days after hatching, the larvae was 27.4 mm ATL already completed all the fins, and preanal length was 59.9% of TL.

Microrasbora Annandale, a new genus record in China, with description of a new species (Teleostei: Cyprinidae)

A new species of genus Microrasbora Annandale (1918), M. microphthalma, is described from the Nanwan River, a tributary of the Ruili River, Irrawaddy drainage, in southwest Yunnan province, China. This new species is the first record of the genus Microrasbora in China. Microrasbora microphthalma can be distinguished from the other species of Microrasbora by the following combination of characters: 15–16 predorsal scales, eye diameter/head length 27–38%, eye diameter/interorbital width 70–93%, predorsal length/ standard length 60–68%, the preanal length/ standard length 65–71% and the origin of dorsal fin is posterior of that of the ventral fin.

Description and ecology of larvae and juveniles of three native cypriniforms of coastal southern California

Larval series of the Santa Ana sucker, Catostomus santaanae (Federally Threatened), arroyo chub, Gila orcutti (California Species of Special Concern), and Santa Ana speckled dace, Rhinichthys osculus (California Species of Special Concern) are described from wild-caught specimens from the Los Angeles and Santa Ana river drainages. Santa Ana sucker larvae are elongate, having 41–46 myomeres and a distinctive paired-triangle patch of melanophores over the midbrain. Melanophores present on the snout, dorsal body, lateral midline, dorsal gut, postanal ventral body, and caudal fin. Preanal length 74–79% in body length (BL), typical of catostomids. Arroyo chub larvae relatively deep-bodied, 36–39 myomeres, and a heart-shaped patch of melanophores over the midbrain with a line of melanophores trailing posteriorly. Heavy pigment present on the snout, lower jaw, dorsal body, lateral midline, gill arches, dorsal gut, postanal ventral body, and caudal fin; short preanal length of 65–72% BL, typical of native North American cyprinids. Santa Ana speckled dace are similar to arroyo chub except for having less pigment on the ventral gut, large distinct melanophores on the ventrolateral caudal peduncle, a wedge-shaped patch of midbrain melanophores with no distinct line trailing posteriorly, and lateral midline melanophores that do not extend anteriorly. These three species often occur together and with nonnative cyprinids. Characters distinguishing them from other local larvae, including southern fathead minnow, Pimephales promelasconfertus and red shiner, Cyprinella lutrensis, are discussed with their habitat preferences.

A systematic and ecological study of Aphanius vladykovi Coad, 1988 (Actinopterygii: Cyprinodontidae) in Iran

A multivariate statistical analysis was performed on the morphological characters of four populations of Aphanius vladykovi. Factor analysis revealed that interlocality morphological variations consist of characters such as total length, predorsal length, preventral length, preanal length, head length, head width and head depth. By using one way ANOVA analysis of 38 meristic and morphometric characters examined for males and females, 33 were significantly different (p<0.05) among all populations. Three localities for Aphanius vladykovi were found for the first time. The species is mainly carnivorous and generally has the same diet at all four stations examined. The gut contents consisted mostly of Diaptomus, Daphniae and filamentous algae. This fish forms schools, swimming and feeding together. Teeth are found in both jaws of the superior mouth in a single row and are tricuspid.

Does eel metamorphosis cause a breakdown in the tenets of otolith applications? A case study using the speckled worm eel (Myrophis punctatus, Ophichthidae)

Several basic tenets of otolith research have been questioned recently with regard to eel metamorphosis. Specifically, some researchers have suggested that otolith increment formation is not daily, and otolith material may be resorped during metamorphosis. We conducted a rearing experiment to test the hypothesis that increment formation is daily and that the otolith continues to grow during eel metamorphosis. We marked the otoliths of wild-caught Myrophis punctatus leptocephali and reared these fish through metamorphosis. Metamorphosis was characterized by a decreasing standard length, pre-anal length, and body depth accompanied by an increase in pigmentation and a change in behavior. Increment formation was daily or near-daily through metamorphosis, and the otolith continued to grow during metamorphosis. Thus, the basic tenets of otolith application apply to eel metamorphosis, and non-daily ring deposition and resorption should not be used as explanations for otolith characteristics of eels (e.g., back-calculated hatch dates) unless demonstrated experimentally.

Food and feeding habits of ribbonfish Trichiurus lepturus in coastal waters of south-western Taiwan

The catch of ribbonfish Trichiurus lepturus in the coastal waters of south-western Taiwan has significantly declined in recent years. To examine the effects of exploitation on the feeding habits of ribbonfish, 1570 specimens were collected on a monthly basis during March 2002-March 2003 from the landings by trawlers operating in the coastal waters of south-western Taiwan. The size of the ribbonfish ranged from 83–298 mm, preanal length (PL), with a peak at 201–250 mm PL. Although they fed on shrimps and squid, fishes including Benthosema pterotum, Bregmaceros lanceolatus and Encrasicholina heteroloba were their main food items. In particular, B. pterotum was the most important food all year except during summer No evidence of cannibalism was found in this study. No differences between day and night were found in the feeding activity of T. lepturus. However, B. pterotum and Acetes intermedius were the most important prey in the daytime, whereas B. lanceolatus, B. pterotum and E. heteroloba were at night. Feeding activity and the number of food items increased with increasing size of ribbonfish. Their feeding intensity in February to June, the main spawning season, was significantly greater than in other months. Changes in the food and feeding habits of this species before and after the recent period of heavy exploitation are discussed in detail in this study.

Morphological development of Pellona flavipinnis post-yolk-sac larvae and juveniles (Clupeiformes: Pristigasteridae)

Pristigasterids are predominantly coastal marine sardines of tropical and subtropical seas, with some species being found in fresh water. Two species of the genus Pellona, P. castelnaeana Valenciennes, 1847 and P. flavipinnis (Valenciennes, 1837), inhabit fresh waters of the neotropical region, with the latter occurring in the Pantanal of Mato Grosso, in the Paraguay River basin of central Brazil. The development of P. flavipinnis larvae and early juveniles was characterized from an ontogenic series of 27 specimens (6.3–35 mm SL), based on morphological and meristic characters. The larval and juvenile development of this freshwater sardine are typical of most clupeiforms. Exact hatching size is unknown, but it is less than 6 mm standard length (SL) and the yolk is absorbed under 10 mm. Transformation to the flexion stage occurs at about 11 mm, to the postflexion stage between 16 and 19 mm, and to the juvenile stage after 26 mm. The ventral scutes begin to form between 25 and 31 mm, with the full complement of scutes (32 to 37) formed between 32 and 35 mm. Total myomere count averages 42. As the dorsal fin and origin of the anal fin and vent migrate anteriorly, the preanal myomere count ranges from 29 in the flexion larvae to 24 in early juveniles up to 35 mm. Corresponding preanal lengths range from 85 to 61%, respectively.

Larval and juvenile Polymetme elongata (Stomiiformes: Phosichthyidae) collected from Suruga Bay and offshore waters, Japan

Two larvae [17.4 mm standard length: SL (postflexion stage)] and 26.1 mm SL (transformation stage)] and a juvenile (31.7 mm SL) of a phosichthyid, Polymetme elongata, from Suruga Bay and offshore waters, central Japan, are described. These specimens had an elongate body with relatively short preanal length (53–63% SL), long anal fin base (2.6–3.4 times dorsal fin base length), and anal fin origin below dorsal fin base, and were further characterized by a blackish flap on each eye and internal clusters of melanophores (e.g., along caudal myosepta around midlateral line and on ventral margin of caudal peduncle). The short preanal length and larval melanophore pattern were very similar to those of another phosichthyid, Yarrella blackfordi, from the Atlantic Ocean.