Takakazu Ozawa

Feeding chronology of the vertically migrating gonostomatid fish, Vinciguerria nimbaria (Jordan and Williams), off southern Japan

The feeding habits of the gonostomatid fish,Vinciguerria nimbaria (Jordan andWilliams), from off southern Japan were studied in relation to its food organisms, process of digestion, and diel vertical migration. Food organisms were composed mainly of small- to moderate-sized copepods which live almost entirely in the 0–200 m epipelagic zone.V. nimbaria appears to feed twice a day; after having migrated to the epipelagic zone in the evening, all individuals fed intensively from 6 to 8 p.m. They then spent the remainder of the night in digestion. Many, but not all, of the individuals foraged again in the morning.

Redescription of Bregmaceros mcclellandi Thompson, 1840 (Gadiformes: Bregmacerotidae)

Abstract This study redescribes Bregmaceros mcclellandi Thompson, 1840, based on one specimen (74.4 mm SL) from the Bay of Bengal and 66 specimens (30.0–84.7 mm SL) from Mumbai (Bombay), India, because the type specimens have apparently been lost. The present specimens are characterized by having black dorsal, pectoral, and caudal fins and show the following morphology: caudal fin slightly forked; body chromatophores present mainly at the dorsal part; no scales on cheek; vertebrae 52–55 (13–15 + 38–41); dorsal rays 52–59; anal rays 54–60; pectoral rays 18–20; caudal rays 27–31 (principal rays 14); transverse scales 14–15. In the 66 Mumbai specimens, it was confirmed that the distinctive black fin pigmentation developed sequentially with growth, with complete pigmentation first on the anterior lobe of the dorsal fin, then simultaneously on the posterior lobe of the dorsal fin, the caudal fin, and the pectoral fin, and last, on the anal fin. This species is known only from the Arabian Sea, Bay of Bengal, and Gulf of Thailand. A review of 16 nominal Bregmaceros species indicates that, besides B. mcclellandi, the distinctive dark fin pigmentation is found in B. atripinnis (Tickell), B. atlanticus Goode and Bean, B. japonicus Tanaka, and B. lanceolatus Shen. B. atripinnis is considered a junior synonym of B. mcclellandi, and the others are clearly distinct from B. mcclellandi. Comments are made on some of the characters to more fully characterize the species and for reference in future revisionary and phylogenetic studies.

Uncisudis posteropelvis, a new species of barracudina (Aulopiformes: Paralepididae) from the western North Pacific Ocean

Six specimens (2 flexion larvae: 9.5–10.4 mm in notochord length; 4 postflexion larvae: 12.3–18.2 mm in standard length) collected from the western North Pacific are tentatively ascribed to the genus Uncisudis of the tribe Lestidiini of the subfamily Paralepidinae (Paralepididae) in sharing remarkably elongate and filamentous pelvic fin rays, their tips reaching the origin of the anal fin. They are described as Uncisudis posteropelvis sp. nov. in uniquely having the insertion of pelvic fins closer to the origin of anal fin than to the posterior end of dorsal fin base among lestidiine species. Addition to this character, the new species has remarkably elongate and filamentous dorsal fin rays, the short distance between anus and origin of anal fin (4.2–6.1% of standard length, SL), the posteriorly located pelvic fins (prepelvic length 69.4–71.5% SL), dorsal fin rays 10, anal fin rays 28–29, myomeres 41–42 + 38–40 = 80–81 (vertebrae 38 + 41 = 79), and peritoneal pigment spots 11–12. The occurrence of larvae differing in pigment pattern from the present new species suggests another undescribed species of Uncisudis in the western South Pacific.

Reexamination of Bregmaceros lanceolatus Shen, 1960 with description of a new species Bregmaceros pseudolanceolatus (Gadiformes: Bregmacerotidae)

Based on our reexamination of the 9 specimens including the neotype, Bregmaceros lanceolatus is recharacterized and diagnosed by the following combination of features: caudal fin rounded; scales present on gill cover; dorsal surface of snout unpigmented or with a few chromatophores; isthmus pigmented with punctate chromatophores; two parapophyses on abdominal vertebrae; dorsal rays (D) 65–74; anal rays (A) 67–74; vertebrae (V) 58–61; longitudinal scales (LS) ca. 82–88; principal caudal rays (PC) 16–18; head length (HL)/standard length (SL) 14.0–15.5%; caudal peduncle depth/SL 3.2–4.2%. Based on 27 specimens, B. pseudolanceolatus sp. nov. is described. This species is closely similar to B. lanceolatus, but is diagnosed by the following combination of features: caudal fin rounded; scales present on gill cover; dense concentration of chromatophores on dorsal surface of snout; isthmus colorless; one board-like parapophysis on the last three abdominal vertebrae; D 58–64; A 58–67; V 52–55; LS ca. 68–77; PC 14–16; HL 15.5–18.4% SL; caudal peduncle depth 4.1–5.2% SL. Bregmaceros pseudolanceolatus is known from around the Taiwan Strait, southern East China Sea, South China Sea, Gulf of Thailand, Timor Sea, Arafura Sea, and eastern Bay of Bengal.

Early ontogeny of a South Pacific gonostomatid fish Sigmops longipinnis

Abstract During the R/V Hakuho-maru Cruise KH-95-2, Ocean Research Institute, University of Tokyo, from Tokyo, Japan to the South Pacific east of Australia (22° N–30° S; 126° E–176° E) from June to September, 1995, 77 unidentified gonostomatid larvae (5.5–20.0 mm SL) were collected south of 20° S with an IKMT net. They subsequently were identified as Sigmops longipinnis (Mukhacheva), and its ontogeny during the latter part of the larval stage (body form and proportions, photophores, pigmentation, and meristics) is described here. The larvae develop a species-specific row of melanophores along the midlateral line anterior to the caudal peduncle and another along the middorsal line from before the dorsal fin to just before the caudal fin.

Age and growth of Lestrolepis japonica (Aulopiformes: Paralepididae) in Kagoshima Bay, southern Japan

Abstract Age and growth of a paralepidid, Lestrolepis japonica, were determined from sagittal otoliths of specimens collected from April 2001 to February 2002 in Kagoshima Bay, southern Japan. Marginal growth increments indicated that the annulus was formed once a year, in August and September. Four groups were recognized, having none, one, two, or three annuli, respectively. Age in months was assigned to each individual on the basis of August as the birth month. The maximum recorded age was 48 months. Growth was expressed by von Bertalanffys equation, Lt = 171.91{1 − exp[−0.148(t + 0.403)]}, t being the age in months and Ltthe standard length (mm) at age t.

Larva of Chascanopsetta lugubris lugubris (Bothidae) disgorged by a lancetfish (Alepisaurus sp.)

Chascanopsetta lugubris lugubris Alcock of the family Bothidae occurs on the sea bottom at depths of 270–595 m in the western Pacific and Indian Ocean (Amaoka and Yamamoto 1984). Bruun (1937), Nielsen (1961), Amaoka (1971), and Ozawa and Fukui (1986) described the larva of this subspecies, which is known to attain 120 mm SL (Amaoka 1971), the largest size known among pleuronectoid larvae. Such large larvae are rarely collected, and their morphological development is not sufficiently understood. Interestingly, gut contents have not been reported from any bothid larvae inclusive of this subspecies. A large larva of this subspecies, 108mm SL, was disgorged on deck by a lancetfish (Alepisaurus sp.) caught in Tasman Sea. The larva was fresh and excellent in condition when it was delivered frozen to the Australian Museum, by officers of NSW Fisheries. It contained many food organisms in its gut. This article describes the larva and the gut contents. The measurement methods followed Ozawa and Fukui (1986), the clearing and staining techniques those of Potthoff (1984), and the institutional abbreviations those of Leviton et al. (1985). The gut contents were found to be a copepod, Scolecithrix danae. The copepods were slightly damaged; therefore, their body lengths were estimated as follows. The length of intact part from the anterior tip of head to the posterior tip of fourth thoracic segment was measured on the specimens from the gut and used to calculate the total body length from the proportions given by Mori (1964). The metasoma of all the contents was intact, and its maximum width was also measured. Chascanopsetta lugubris lugubris Alcock (Figs. 1, 2)

Early ontogeny of two bothid species, Psettina iijimae and Laeops kitaharae

From specimens collected in the western North Pacific, the early ontogeny ofPsettina iijimae andLaeops kitaharae is described. Diagnostic characters of the genera throughout larval stages are also provided. It is suggested that these species are distributed on continental shelf or at the edge, and that they spawn between July and September.

Occurrence and abundance of bregmacerotid larvae in Kagoshima Bay, southern Japan, with descriptions of ontogenetic larval characters

Regular collections of ichthyoplankton were made with a larva net at 9–14 stations from Oct. 1983 to Dec. 1988 in Kagoshima Bay, totalling 817 collections from 66 cruises. A total of 2172 bregmacerotid larvae obtained from 195 collections of 33 cruises were identified asB. atlanticus (2001),B. neonectabanus (169),B. macclellandii (1) andB. nectabanus (1, tentative identification). The peaks of mean densities of larvae collected occurred in autumn forB. atlanticus andB. neonectabanus. The larvae ofB. atlanticus occurred throughout the bay, and their densities and frequency of occurrence were lower in the northern part of the bay. In the southern part of the bay, stations in its southwest quadrant showed higher densities than the others. The larvae ofB. neonectabanus occurred only in the southern part of the bay in which stations in the northwest quadrant showed higher densities than the others.

Seasonal Change in Stomach Contents of Silvergray Seaperch.

鹿児島湾産オオメハタ151個体(体長66a178mm)の胃内容物を調査した。餌生物は3綱10目22科に同定され, カラヌス目かいあし類が多様で多数出現した。全ての餌生物種あるいは属のサイズはオオメハタの成長に伴い増大した。四季にわたり採集された体長階級101-120mmにおける摂餌量には4つの季節間で統計的有意差はなかった。餌生物として春季にはベントスに次いで動物プランクトンが, 他の季節では動物プランクトンが優占した。魚類が春季から季節を経るにつれ増加した。