Early osteological development of the fins in the hatchery-reared red porgy, Pagrus pagrus (L. 1758)

The present study was undertaken to establish the normal, healthy features of morphological structures at various developmental stages as achieved under well-defined environmental culture conditions (temperature between 16 and 21°C, salinity 36 ppt, pH around 7.6, and oxygen saturation over 95%) common in aquaculture of the species. The pectoral fin supports began to develop at 2.90 mm total length (TL), followed by those of dorsal fins at 5.5 mm TL, caudal fins at 5.6 mm TL, pelvic fins at 5.9 mm TL and anal fins at 6.0 mm TL. The pelvic fins appeared fully at 7.4 mm TL. Development of dorsal lepidotrichia was first observed at 6.9 mm TL, attaining their final number at 7.6 mm TL. The dorsal spines first appeared at 6.5 mm TL and were complete at 7.4 mm TL. The anal lepidotrichia appeared during the development phase from 6.8 to 8.6 mm TL. At 5.6 mm TL, the upward flexion of the urostyle was initiated. The caudal lepidotrichia formed within the primordial fin at 5.6 mm TL and reached the final count at 7.4 mm TL. The caudal dermatotrichia first appeared at 7.3 mm TL and all forms were observed by 15.5 mm TL. The development pattern of fin supports found in Pagrus pagrus is quite similar to that described for other Sparid species.     

Morphogenesis in hatchery-reared larvae of the black rockfish,Sebastes schlegeli,and its relationship to the development of swimming and feeding functions

The developmental sequence of morphological characteristics related to swimming and feeding functions was investigated in hatchery-reared larvae and juveniles ofSebastes schlegeli, a viviparous scorpaenid. The fish were extruded at an early larval stage, when the mean body size was 6.23 mm TL. Fin-ray rudiments became visible at 9.0 mm TL in the dorsal and anal fins, at 8.0 mm TL in the pectoral and pelvic fins and 6.0 mm TL (size at extrusion) in the caudal fin. Completion of segmentation of soft rays in the dorsal and anal fins was attained by 14 mm TL and in all fins by 17 mm TL. Branching of soft rays in the respective fins started and was completed considerably later than the completion of segmentation, as well as ossification of the fin-supports. Morphological transformation from larva to juvenile was apparently completed by about 17 mm TL. Although the completion of basic juvenile structures was attained by transformation at that body size, succeeding morphological changes occurred between 17 mm and 32 mm TL. Newly-extruded larvae possessed one or two teeth on the lower pharyngeal and pharyngobranchials 3 and 4, but lacked premaxillary, dentary, palatine and prevomer teeth. The fish attained full development of gill rakers and gill teeth by 15 mm TL, the upper and lower pharyngeal teeth subsequently developing into a toothplate. Development of the premaxillary, dentary and palatine teeth was completed at about 30 mm TL, by which time loop formation of the digestive canal and the number of pyloric caeca had attained the adult condition. The developmental sequence of swimming and feeding functions during larval and early juvenile periods appeared to proceed from primitive functions to advanced or complex ones, from the ability to produce propulsive force to that of swimming with high maneuverability and from development of the irreducible minimum function of passing food into the stomach to the ability to actively capture prey via passive food acquisition with the gill rakers and gill teeth. The relationship of morphological development to the behavior and feeding activity of artificially-produced hatchlings is also discussed.     

New genus and species of the family stichaeidae from Hokkaido,Japan

Specimens of a new genus and species of the stichaeid fish,Leptostichaeus pumilus, were collected from the Okhotsk Sea off Hokkaido in Japan. The present new genus and species clearly differs from all the other genera and species of the stichaeid fishes in the following characters: 3 or 4 pectoral fin rays; 10 or fewer caudal principal rays; 79–82 dorsal spines; no pelvic fin; last interneural spine supporting a single dorsal spine; infraorbital, occipital and lateral line canals absent; moderate size of dorsal spine shorter than eye diameter; membranes of dorsal and anal fins widely connected with caudal fin; a large black spot divided by a yellow band present just above gill cover.     

Embryonic and morphological development of larvae and juveniles of the Amberjack,Seriola dumerili

Embryonic and morphological development of larvae and juveniles of the amberjack,Seriola dumerili Risso, are described using specimens raised at Yaeyama Station (Ishigaki Island, Okinawa Pref.), Japan Sea Farming Association. The specimens obtained from brood fish (3 females, 3 males) were treated with gonadotropin and spawned on 6th of April 1987. The eggs of amberjack are pelagic, spherical in shape and 1.01–1.17 mm in diameter. The yolk is roughly segmented and has a single oil globule 0.22–0.24 mm in diameter. The perivitelline space is narrow. During development, a few melanophores and no xanthophores were observed on yolk. Hatching took place 35 hrs. 15 min. after spawning out at temperatures 23.1–23.7°C. The newly hatched larvae were 2.84–3.04mm in TL with 27 (13+14) myomeres and an oil globule anteriorly situated beyond the head. 3 days after hatching 4.00 mm TL, the mouth opened. 10 days after hatching 4.26 mm TL, small denticles appeared on the margin of the upper jaw and there were 1 anterior and 2 posterior preopecular spines. At 5.96mm TL, notochord was slightly flexed. Caudal, dorsal and anal fins with rudiments of rays appeared at 8.00 mm TL. The specific numbers of all fin rays and spines were obtained in a juvenile 9.60 mm TL. In a juvenile 34.25 mm TL, 54 days after hatching, the characteristic brown band of amberjack had appeared on head. Some notable changes in relative growth were observed at 5 mm and 15 mm in TL.     

Larval development of the Common Ponyfish, Leiognathus equulus (Teleostei: Leiognathidae)

Larval development of Leiognathus equulus is described from reared postflexion specimens (4.6–15.8 mm Standard Length, SL) from Taiwan. Larvae have strong head spination, particularly a supraoccipital crest, strong supraocular ridge and very long, serrate preopercular spines, with the spine at the preopercular angle initially heavily pigmented. Fin spines are robust, and the anterior spines of dorsal, anal and pelvic fins are long and serrate. Structures characteristic of the family Leiognathidae form early in development (ca. 5 mm SL), including the very protrusible mouth, the fin-locking mechanism and the bacterial light organ. Pigment is initially largely confined to the ventral midline, but as development proceeds, extensive lateral and dorsal pigment patches appear. Larvae of L. equulus have the Trnski and Leis Morph 1 morphology.     

Larval development of Pseudorhombus oculocirris and P. arsius (Pleuronectiformes, Paralichthyidae) from off southern Japan

 Larvae of two paralichthyids, Pseudorhombus oculocirris and P. arsius, are described and illustrated from specimens collected off Tosa Bay, southern Japan. Peudorhombus oculocirris larvae (5 specimens, 4.5–7.8 mm BL) are characteristic in having 6 or 7 elongated anterior dorsal fin rays and poorly developed head spines and melanophores on the tail. Pseudorhombus arsius larvae (3 specimens, 5.3–8.4 mm BL) are distinctive in having 11 or 12 elongated anterior dorsal fin rays and well-developed head spines, including a row of spines on the sphenotic. Received: June 28, 2001 / Revised: November 2, 2001 / Accepted: November 22, 2001     

Growth and morphological development of larval and juvenileepinephelus bruneus (perciformes: Serranidae)

The growth and morphological development of larval and juvenileEpinephelus bruneus were examined in a hatchery-reared series. Average body length (BL) of newly-hatched larvae was 1.99 mm, the larvae growing to an average of 3.96 mm by day 10, 6.97 mm by day 20, 12.8 mm by day 30, 22.1 mm by day 40 and 24.7 mm by day 45 after hatching. Newly-hatched larvae had many mucous cells in the entire body epidermis. By about 4 mm BL, the larvae had developed pigment patterns peculiar to epinepheline fishes, including melanophores on the dorsal part of the gut, on the tips of the second dorsal and pelvic fin spines, and in a cluster on the ventral surface of the tail. Spinelets on the second dorsal and pelvic fin spines, the preopercular angle spine and the supraocular spine, had started to develop by about 6 mm BL. The notochord tip was in the process of flexion in larvae of 6–8 mm BL, by which time major spines, pigments and jaw teeth had started to appear. Fin ray counts had attained the adult complement at 10 mm BL. After larvae reached 17 mm BL, elements of juvenile coloration in the form of more or less densely-pigmented patches started to appear on the body. Squamation started at 20 mm BL. Major head spines had disappeared or became relatively smaller and lost their serrations by 20–25 mm BL.     

Neolumpenus unocellatus,a new genus and species of stichaeid fish from Japan

Neolumpenus unocellatus gen. et sp. nov., a stichaeid fish (subfamily Lumpeninae,sensu Makushok, 1958) is described on the basis of a single specimen found in the stomach of the Pacific cod,Gadus macrocephalus Tilesius, caught off Akkeshi, Hokkaido, Japan. The new genus and species is distinguished from all other lumpenines in having the following combination of characters: 1) 51 dorsal spines, 33 anal fin rays, 57 total vertebrae; 2) broad pelvic fin with deeply-branched soft rays; 3) lower rays of pectoral fin branched and not prolonged backward; 4) prevomerine and palatine teeth present; 5) pungent spines present in pelvic and anal fins; 6) upper lip fused to snout anteriorly; 7) gill openings not extending forward beyond a vertical through posterior margin of eye; 8) minimal (fifth) hypural present; 9) first interneural spine inserted between first and second neural spines; 10) extremely large cephalic sensory pores present; 11) high, steep snout; 12) ocellus on dorsal base of caudal fin.     

Development of eggs,larvae and juveniles of the labrid fish,Halichoeres poecilopterus,reared in the laboratory

Embryonic, larval and juvenile development of the labrid fish,Halichoeres poecilopterus, is described using a laboratory-reared series. The eggs, measuring 0.60–0.72 mm in diameter, were pelagic and spherical with a single oil globule (0.12–0.16 mm in diameter). Hatching occurred 18 h 48 min after spawning. The newly-hatched larvae, measuring 1.46–1.70 mm TL, had 8–114 + 16–18 myomeres. A conspicuous melanophore appeared on the dorsal finfold 8 h after hatching, at ca. 2 mm TL. The yolk was completely absorbed 3 days after hatching, at 2.52–2.72 mm TL. Flexion of the notochord started at ca. 6 mm TL and was finished at ca. 8 mm TL. Aggregate numbers of all fin rays were completed at ca. 14 mm TL. Squamation was almost completed at ca. 20 mm TL.     

New record of the golden grouper <Emphasis Type="Italic">Saloptia powelli</Emphasis> (Perciformes: Serranidae) from North Sulawesi,Indonesia

One specimen (300 mm in standard length) of Saloptia powelli, belonging to the family Serranidae, was newly collected in a local fish market in Manado, North Sulawesi, constituting a new record for the species in the Indonesian archipelago. This species was diagnosed by the following morphological traits: dorsal rays VIII—11, anal rays III—8, well-defined opercular spines, pelvic fins below pectoral fins, caudal fin emarginate, mouth moderate in size, supplemental maxillary present, fine teeth in irregular rows on vomer and palatines. Head, body, and fins yellow in color. We suggest “kerapu emas”, a translation of its existing common name “golden grouper”, for the Indonesian species names.     

Structure of supporting elements in the dorsal fin of percid fishes

The dorsal fin is one of the most varied swimming structures in Acanthomorpha, the spiny‐finned fishes. This fin can be present as a single contiguous structure supported by bony spines and soft lepidotrichia, or it may be divided into an anterior, spiny dorsal fin and a posterior, soft dorsal fin. The freshwater fish family Percidae exhibits especially great variation in dorsal fin spacing, including fishes with separated fins of varying gap length and fishes with contiguous fins. We hypothesized that fishes with separated dorsal fins, especially those with large gaps between fins, would have stiffened fin elements at the leading edge of the soft dorsal fin to resist hydrodynamic loading during locomotion. For 10 percid species, we measured the spacing between dorsal fins and calculated the second moment of area of selected spines and lepidotrichia from museum specimens. There was no significant relationship between the spacing between dorsal fins and the second moment of area of the leading edge of the soft dorsal fin.     

Morphological development of larval and juvenile Alectis indica (Perciformes: Carangidae) reared in captivity

Larvae and juveniles of Alectis indica reared in captivity are described based on 47 specimens (3.2–32.0 mm in body length: BL). Development was typical for the tribe Carangini except for the presence of elongated fin filaments. Elongated dorsal-fin filaments were present at preflexion (3.2 mm BL). During flexion, the anal- and pelvic-fin rays elongated and the body deepened. The full complement of fin spines and rays was present by 7.1 mm BL. The larvae of A. indica could be differentiated from those of Alectis ciliaris, which also inhabits in the Indo-Pacific waters, by the presence of a ventral series of melanophores on the tail, elongated pelvic fins, and the timing of anal-fin spine migration. The rounded body and elongated fin rays of A. indica cause it to resemble venomous Cubomedusae.     

Larval development of Hypsophrys nicaraguensis (Pisces: Cichlidae) under laboratory conditions

The cichlid Hypsophrys nicaraguensis is a popular fish known as butterfly, and despite its widespread use as pets, little is known about its reproductive biology. In order to contribute to this knowledge, the study describes the relevant larval development characteristics, from adult and larval cultures in captivity. Every 12h, samples of larvae were collected and observed under the microscope for larval stage development, and every 24h morphometric measurements were taken. Observations showed that at 120h, some larvae had swimming activity and the pectoral fins development was visible; at 144h, the dorsal fin appear and all larvae started food intake; at 168h, the formation of anal fins begins, small rudiments of pelvic fins emerge, the separation of caudal fin from anal and dorsal fins starts, and the yolk sac is reabsorbed almost completely; at 288h, the pelvic fins starts to form; at 432h, the rays and spines of dorsal and anal fins can be distinguished, both the anal and the dorsal fins have the same number of spines and rays as in adults. After 480h larvae have the first scales, ending the larval stages and starting the transformation to fingerlings. Larvae were successfully fed with commercial diet.     

Pseudanthias calloura (Teleostei: Perciformes), a new serranid fish from Palau, Central Pacific

A new anthine fish, Pseudanthias calloura, is described on the basis of three specimens from Palau. The new species differs from other congeners in having a complicated color pattern of the caudal fin and the following characters: moderately forked caudal fin; dorsal fin with 10 spines, the anterior ones being shorter than the rest, and with 16 soft rays; second anal spine shorter than the third; 19 pectoral rays; scales on lateral line 51 (holotype) to 53 (paratypes) in number; tongue without teeth; circumorbital rim with several fleshy projection on posterior part; a row of fine scales occurring asymmetrically behind alternate dorsal spines on both left and right sides; preopercle margin finely serrated; interopercle and subopercle margins smooth. Received: June 9, 1999 / Revised: September 23, 2000 / Accepted: February 23, 2001     

Selenoscopus turbisquamatus,a new genus and species of Uranoscopid fish from Japan and the Norfolk Ridge

A new stargazer,Selenoscopus turbisquamatus, is described from 30 specimens from the Kyushu-Palau Ridge, the coasts of Kii Peninsula, Japan, and the Norfolk Ridge, northern Tasman Sea. The species appears to be most closely related to the genusUranoscopus in having two dorsal fins, a spinous dorsal fin consisting of feeble spines, a stout cleithral spine, an externally visible pelvic spur, two supracleithral spines, and no postcleithrum, but differs from it in having a smooth posterior margin of the gill flap, uniserial dentary teeth, random arrangement of body scales, no subopercular spine, an intervention of the pterosphenoid (=alisphenoid) between the frontal and the parasphenoid, and the first and second haemal spines depressed on the centra. A new genus,Selenoscopus, is therefore proposed, based on these characters.     

Description ofGerres chrysops sp. nov. From Thailand and redescription ofGerres setifer (Hamilton, 1822) andG. Decacanthus (Bleeker, 1865) (perciformes: Gerreidae)

Gerres chrysops, a new gerreid species from the Gulf of Thailand, is described on the basis of 29 specimens, 58–83 mm in standard length (SL). A small-sized species (less than 100 mm SL), it is characterized by a silvery-gold sheen on the head and trunk, vivid yellow or yellowish-hyaline fins in life, two supraneural bones (formula 0/0/2/) and dorsal fin rays usually IX, 10. The new species is similar toG. decacanthus (Bleeker, 1865) andG. setifer (Hamilton, 1822), which are redescribed. being similarly small valid gerreid species characterized by two supraneural bones. Together, the three species comprise “theGerres setifer complex.”Gerres chrysops differs from bothG. decacanthus andG. setifer in life and fresh colors, the body being silvery-gold with vivid yellow or yellowish dorsal, caudal, anal and pelvic fins, and yellowish-hyaline pectoral fins (vs. silver body with hyaline fins in the latter two species).Gerres setifer differs fromG. chrysops andG. decacanthus in having the last dorsal fin spine longer than the penultimate spine (vs. almost same length or shorter), usually ten dorsal fin spines and nine soft dorsal rays (vs. usually IX, 10), and 8 or 9 lower series gill rakers (vs. usually 7).Gerres decacanthus differs fromG. chrysops andG. setifer in having a shorter head, lesser body depth at the first anal fin spine base, lesser body width at the pectoral fin base, and shorter second dorsal and third anal fin spines. The new species is currently known only from Angsilla, near Bangsaen, and around Si Chang Island, northeastern Gulf of Thailand.Gerres decacanthus inhabits southern Chinese waters andG. setifer is currently known from the Bay of Bengal to the Andaman Sea.     

A new species,gerres infasciatus, from the gulf of thailand (perciformes: Gerreidae)

Gerres infasciatus sp. nov. is described from the holotype and two paratypes, 125–140 mm in standard length (SL), collected off Samut Prakan, northern Gulf of Thailand. The species is similar toG. filamentosus Cuvier andG. macracanthus Bleeker in general appearance, having an elongated second dorsal fin spine, but differs from them in having 39 or 40 pored lateral line scales, the first and second soft dorsal fin ray tips yellow in fresh specimens, a narrow, faint dusky-yellowish margin on the upper membrane of the spinous dorsal fin (between 4th–9th spines), the distal part of the pelvic fin (between 1st–5th soft rays) white for 1/3–1/2 of each ray length (lost after preservation), bands absent on the body in both fresh and preserved specimens, a smaller orbit diameter (11.4–12.4% of SL), a longer second dorsal fin spine (48.0–68.9% of SL), and shorter second and third anal fin spines (10.7–11.2% and 10.4–11.3% of SL), respectively.     

Early life history of a seahorse, Hippocampus mohnikei, in Tokyo Bay, Japan

The early morphological development, seasonal and spatial occurrence patterns, and food habits of a seahorse, Hippocampus mohnikei, in offshore waters of Tokyo Bay, central Japan, were studied on the basis of 206 juvenile and young specimens (6.0–65.3 mm TL) collected between August 1995 and January 1999. All the specimens were collected within the period from May to January, inclusive, each year. In the least developed specimen (6.0 mm TL), the number of dorsal, anal, and pectoral fin rays had attained the adult complement, whereas the minute caudal fin, consisting of two rays, was present in juveniles of 6.0–26.4 mm TL. Hippocampus mohnikei≧35 mm TL, being larger than settlement size (ca. 30 mm TL), had very low gut fullness index values (GFI = 0, >70% of specimens), whereas those of 15–29 mm TL had higher values (GFI = 2–4, >80% of specimens). In addition, larger individuals selectively fed on larger planktonic animals (species of Brachyura), which occurred naturally at low densities, although smaller food items, such as Oithona davisae and Penilia avirostris, occurred abundantly, being consumed by smaller H. mohnikei individuals (15–34 mm TL). These results indicated that food availability for H. mohnikei in offshore waters of Tokyo Bay is significant for individuals larger than settlement size, because their food preference would shift from smaller food items to larger food items, which would be scarce in their environments. Received: January 12, 2001 / Revised: May 13, 2001 / Accepted: June 14, 2001     

Ontogeny of the mandarinfish <Emphasis Type="Italic">Siniperca chuatsi</Emphasis> (Perciformes: Sinipercidae) reared in aquarium

Early-stage morphologies of the mandarinfish Siniperca chuatsi are described on the basis of an ontogenetic series of reared specimens in an aquarium. Spherical eggs (diameter 1.70–1.82mm) with a single oil globule (0.40–0.48mm) were free-demersal and easily floated when agitated. Hatching occurred about 3 days after spawning at about 24°C. Newly hatched larvae (3.8–4.2mm in notochord length: NL) had many melanophores on the yolk sac. After reaching ca. 5.5mm NL (8–9+19–20=27–28 myomeres), larvae had almost completely absorbed the yolk, possessed a large mouth and sharp teeth, and were starting to prey on other fish larvae. Three large preopercle spines appeared at ca. 5.5mm NL, five spines by ca. 8.5mm NL, and eight by ca. 21mm in standard length (SL). The interopercle bore a single spine at ca. 8.5mm NL and two spines at ca. 13.5mm SL. A single spine appeared at the supracleithrum and another at the opercle at ca. 10mm SL. Dorsal fin spines and pelvic, anal, and caudal fins were completed at ca. 10mm SL. Dorsal fin rays and pectoral fins were completed at ca. 13.5mm SL. Four ontogenetic characters (free-demersal eggs, large jaws with large teeth, conspicuous head spination, and precocious completion of dorsal fin spines) are rare among freshwater percoids.     

Chromis okamurai,a new damselfish from the Okinawa Trough,Japan

A new pomacentrid fish,Chromis okamurai, is described from a single specimen taken from the Okinawa Trough (25°53.4′N, 123°59.4′E), in 135–175 m. This species is most closely related to the deep-dwellingC. mirationis, sharing with it the same meristic data (in particular XIV dorsal spines and 2 upper and lower caudal spinules), large eye, and relatively deep body. It differs in having a small round posterior nostril (large and slit like inmirationis), longer second anal spine, shorter pelvic fins, and in color: two dark brown stripes on body and a pale pectoral-fin axil (mirationis has a single, midlateral, yellow to yellowish brown stripe which extends broadly onto lower part of caudal fin, and a black pectoral axil).