Larvae and juveniles of blue drum,Nibea mitsukurii,occurring in the surf zone of Tosa Bay,Japan

A total of 211 larval and juvenileNibea mitsukurii (4.0–19.0 mm SL) was collected with a small seine in surf zones of Tosa Bay during the period of May 1981 to June 1984. They had morphological characteristics common to the larvae and juveniles of Sciaenidae, but were distinguished from the others by the distribution pattern of melanophores on body and spines at the anterior tip of maxillary. They occurred only in surf zone of Tei out of three locations facing Tosa Bay from middle May to middle August. Temperatures and salinities at the place when they were collected ranged from 21.7 to 29.5°C and from 24.5 to 31.3‰, respectively. Good catches were observed when minute dusts floated abundantly in the surf zone. In past studies using traditional larval nets or minnow-nets in coastal or shallow waters of Tosa Bay, larval and juvenileN. mitsukurii were not reported. It seems that they occur in association with minute dusts in extremely shallow waters such as surf zones.     

Larvae and Juveniles of Temperate Bass, <Emphasis Type="Italic">Lateolabrax latus</Emphasis>, Occurring in the Surf Zones of Tosa Bay,Japan

A total of 343 larval and juvenile Lateolabrax latus (9.2–27.0 mm TL) was collected with a small seine in surf zones of Tosa Bay. They are very similar in general morphology to those of the closely related L. japonicus, but can be distinguished from them by the distribution pattern of melanophores on the tail, head spination, proportion of head length to standard length and the 15 or 16 dorsal fin soft-rays. They occurred in surf zones of Tosa Bay from early January to middle May, being most abundant in middle April. Temperatures and salinities of waters where any number of them were collected ranged from 12.2 to 24.0°C and from 23.7 to 34.5%, respectively. Larval and juvenile L. latus have not been reported so far in coastal and shallow waters, and eelgrass beds of southern Japan. It may be possible that they have been confounded with those of L. japonicus. Their occurrence seems to be limited in extremely shallow waters such as surf zones.     

Feeding habit of larval and juvenile ayu,Plecoglossus altiyelis in the surf zone of Tosa Bay,Japan

A total of 7,000 larval and juvenilePlecoglossus altivelis was collected at semimonthly intervals with a small seine in a surf zone of Tei beach facing Tosa Bay during the period of June 1982 to May 1983. They occurred in the surf zone from middle October to middle May. About 500 larvae and juveniles (10.9–59.9 mm TL) were used to examine their feeding habit. The feeding incidences by collection dates fluctuated from 0 to 100%, with 90.6% in total incidence. They fed mainly on copepods (e.g.Paracalanus parvus andOithona spp.) throughout postlarval and juvenile stages, while they first took small benthic animals at 53.0 mm TL. Their food compositions were influenced fundamentally by the planktonic fauna of the surf zone, but larvae under 20 mm TL tended to take relatively larger copepods.     

Larvae of two pleuronectiforms, Poecilopsetta plinthus (Poecilopsettidae) and Parabothus coarctatus (Bothidae), from southern Japan

Pelagic larvae of two pleuronectiforms, Poecilopsetta plinthus (Poecilopsettidae) and Parabothus coarctatus (Bothidae), are described and illustrated based on specimens collected off Tosa Bay, southern Japan. Postflexion larvae (8.2–11.9 mm BL) of Poecilopsetta plinthus are characteristic in having a series of melanophore patches along the dorsal and anal fin bases and the inner margins of the pterygiophore zones, and linear myoseptal pigmentation also along the inner margins of the latter. Preflexion and flexion larvae (5.0–6.3 mm BL) of Parabothus coarctatus are distinctive in having the dorsal fin origin located level with the dorsal margin of the eye and seven elongated rays in the anterior part of that fin. Received: November 18, 2000 / Revised: May 1, 2001 / Accepted: June 13, 2001     

A pelagic larva of <Emphasis Type="Italic">Plagiopsetta glossa</Emphasis> (Pleuronectiformes,Samaridae), characterized by a trailing gut and S-shaped pelvic bone: description and phylogenetic considerations

 The pelagic larval stage of a pleuronectiform samarid, Plagiopsetta glossa, is described and illustrated, for the first time, from a 8.4-mm BL postflexion specimen collected off Tosa Bay, southern Japan. The larva is distinctive in having broad, semitransparent pterygiophore zones on the dorsal and anal fins, a trailing gut, flexible S-shaped pelvic bone, and a skin fold under the throat. These characteristics are shared with poecilopsettid larvae, suggesting a close relationship between the two families.     

Development of eggs,larvae and juveniles of the puffer,Takifugu chrysops,reared in the laboratory

The artificial fertilization of the puffer,Takifugu chrysops (Hilgendorf), was carried out at Sajima in Yokosuka City on May 22, 1984. Hatched larvae were reared for a period of about 150 days. The spawning period seems to extend from mid to late May in the eastern part of Sagami Bay. The eggs were spherical, pale milky white and semitransparent, demersal and adhesive in nature, measuring 1.32±0.04 mm in diamter, and with a cluster of small oil-globules. The incubation period was about 162 hours at a water temperature of 17.4 to 21.8°C. During embryonic development, the only pigment cells that appeared on the embryo were the black chromatophores. The newly hatched larvae measured from 2.72 to 3.06 mm TL, averaging 2.87±0.1 mm TL, and 22–23 (9 + 13?14) myomeres. At yolk absorption, 4 days after hatching, the larvae attained 3.64–3.79 mm TL. On the 11th day, postlarvae averaged 4.69±0.24 mm TL. Larval finfolds disappeared and rudimental dorsal, anal and caudal fins were formed. There were two large clusters of melanophores, one on the back, exteding from the mid-base of the dorsal fin to the caudal peduncle region, the other along the anal fin base. The color of the body began to turn pale green to brownish-orange and spinelike scales appeared on the belly. Eighteen days after hatching (7.02±0.27 mm TL), the caudal notochord began to turn up and a “constriction” appeared on the posterior margin of the caudal fin membrane. This notch moved upwards as the notochord upturning advances. The larvae attained full fin ray counts and reached the juvenile stage at 9.1-9.5 mm TL, 24 days after hatching. Characteristic black blotches on the back and specific brownish orange body color appeared at the stage of 20 mm TL, 24 days after hatching. The growth during the larval stage and early juvenile stage (24 to 51 days after hatching) were expressed by the following equations, wherey is total length (mm) andx is days after hatching.y ₁=2.8424× 1.0509⁹ (0≦x≦24)y ₂ = 3.7872×1.0372^x (24≦x≦51)     

A larva of Coryphaenoides pectoralis (Gadiformes: Macrouridae) collected by deep-sea submersible from off Hokkaido, Japan

A late-stage larva of Coryphaenoides pectoralis was first observed in situ and subsequently collected by the deep-sea submersible “Shinkai 2000” from mesopelagic waters at a depth of 530 m off Hokkaido, Japan. The larva (14.5 mm in head length, 149+ mm in total length) has fan-like pectoral fins, elongate first dorsal fin, pelvic fin and tail, 10 first dorsal rays (including 2 pseudospines), and 7 pelvic fin rays, 6 branchiostegal rays, no light organ, anus just anterior to anal fin origin, 2 retia and gas glands, 14 abdominal vertebrae, and previously reported larval pigmentation. Counts of second dorsal and anal fin rays, and caudal vertebrae, are reported for the first time.     

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.     

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     

Early development of fin-supports ani fin-rays in the milkfishChanos chanos

Development of fin-supports and fin-rays was observed in larval and juvenileChanos chanos, Chondrification of the caudal complex started at 4.70 mm SL. Ossification of the caudal elements started at 7.80 mm SL and was nearly completed at about 30 mm SL. Cartilaginous fusion of caudal elements, which occurs in hypurals of higher teleostean fishes but is not seen in lower teleosts, was observed between the neural arch of the preural centrum 1 and that of the ural centrum 1 via a small cartilage bridging the distal tips of the two arches. Caudal finrays began to develop at 6.60 mm SL, and an adult complement of principal rays was attained at 7.35 mm SL. Dorsal and anal pterygiophore elements were first evident at 6.70 mm and 6.65 mm SL, respectively. All proximal radiais were formed at 8.15 mm SL in both fins. Formation of dorsal and anal fin-rays started simultaneously at 8.60 mm SL, and adult fin-ray complements were attained at 10,00 mm and 10.70 mm SL, respectively. In the pectoral fin, the cleithrum, coraco-scapular cartilage and blade-like cartilage (fin plate) had already been formed at 4.65 mm SL. The mesocoracoid was observed to originate from the coraco-scapular cartilage and become detached from it in the course of ossification. Pectoral fin-ray formation started at 13.80 mm SL and was completed in number of rays at 20.00 mm SL. In the pelvic fin, the basipterygium was first evident at 13.00 mm SL. Pelvic fin-rays appeared at 13.80 mm SL and attained their adult count at 17.15 mm SL.     

Density,length distribution,and diet of age-0 arctic charrSalvelinus alpinus in the surf zone of Thingvallavatn,Iceland

Synopsis Population densities of age-0 arctic chaff in the surf zone averaged 1.83 and 4.70 fish m^-2 in August 1984 and June 1985, respectively. Length variation of the littoral fish was low in early summer, increasing in late summer and autumn. Newly emerged charr, ∼ 20 mm long, appeared in the stony shallow water zone during both May and June. From length variation and variation in mouth position of the young charr, it is concluded that at least two of the four chaff morphs in the lake are present in the surf zone during spring and summer. In August, some of the larger age-0 charr had moved out from the surf zone, into the pelagic and the deeper epibenthic waters. The food of young littoral charr was dominated by large chironomid larvae (instar 3 and 4) and pupae Contribution from the Thingvallavatn project     

Jetski-based plankton towing as a new method of sampling larval fishes in shallow marine habitats

I tested jetski-based plankton towing as a new method of sampling larval fishes in a shallow marine environment in warm temperate South Africa. Larval fishes were collected by towing a stainless-steel ring net behind a three-man jetski. The sampling technique was designed and tested to overcome problematic sampling of shallow sandy beach surf zones and the adjacent, shallow nearshore immediately seaward of the surf zone (behind the breaker line) with the same type of equipment. The composition, density, stage of development, estuary association, and length frequency of larval fish catches obtained by the new sampling method in the surf zone and in the adjacent shallow nearshore were compared. The success of the technique was evaluated by determining the extent of replication of known trends observed in other surf studies in the same climatic region of South Africa using either a seine or pushnet. Preflexion and postflexion larval fishes were collected. Larvae of the family Sparidae dominated the catches. Trends in catch composition, estuary association, and length frequency of the larvae were similar to those found in other studies of warm temperate South African surf zones. Density of larvae varied depending on the type of equipment used, although these results are tentative given the subjectivity of calculation of the water volume sampled and the extent of nursery use by larvae in the habitats sampled in each study. Increased towing times are recommended. Jetski-based plankton towing is a useful alternative technique for sampling larval fishes in shallow habitats and can easily be applied in surf zones, shallow nearshore areas, and estuaries. The technique greatly increases sampling agility in previously problematic sampling areas.     

A new prickly dogfish,Oxynotus japonicus,from Japan

Oxynotus japonicus sp. nov. is described on the basis of a specimen collected by a bottom trawl at depths between 225 m and 270 m in Suruga Bay, Japan. It differs from other species of the genus in having the following combination of characters: spines of 1st and 2nd dorsal fins sloping slightly backward; length from tip of 1st dorsal spine to apex of 1st dorsal fin 2.6 times vertical height from tip of spine to fin base; length from tip of 2nd dorsal spine to apex of 2nd dorsal fin 1.9 times vertical height from tip of spine to fin base; and 2nd dorsal base 1.3 in interspace between 1st and 2nd dorsal fins.     

Development of juveniles of four flatheads (Perciformes, Platycephalidae) occurring in southern Japan

The juvenile development of four Japanese flatheads (Platycephalidae),Onigocia macrolepis. O. spinosa, Inegocia japonica andRogadius asper, is described and illustrated from specimens trawled in Tosa Bay, southern Japan. Juveniles of twoOnigocia species are diagnosed by an ocular flap and absence (O. macrolepis) or presence (O. spinosa) of distinct dark bars on the body.Inegocia japonica juveniles are distinctive in having a heavily pigmented body and 12 dorsal and anal fin soft rays.Rogadius asper has a unique antrorse preopercular spine prior to 15 mm SL. During the early juvenile stage, strongly negative allometric growth occurs in the interorbital region, accompanied by migration of the eyes from the lateral to dorsal surface of the head.     

Larvae of Diagramma pictum (Haemulidae) from Tosa Bay, Japan

Preflexion to postflexion larvae (2.1–8.0 mm) of Diagramma pictum (Haemulidae) occur in coastal Tosa Bay, Japan from May to September. They can be distinguished from the other haemulid larvae by head spination, location of anus, and melanophore patterns. Compared with larvae identified as the same species from Australia, there are significantly morphological differentiations between the two areas. Thus, these significant differences are likely a reflection of subspecific differences.     

The distribution of cirripede larvae (Cirripedia: Thoracica) in the Amursky and Ussuriisky bays of the Sea of Japan

Based on data from plankton surveys that were carried out in the waters of the Amursky and Ussuriisky bays of the Sea of Japan from May to October 2007 and 2008, the species composition, time of occurrence, density, and distribution of cirripede larvae (Cirripedia: Thoracica) were studied. The larvae of five species of this group were revealed. Their average density does not exceed 400 ind./m3 and their proportion in the total meroplankton does not exceed 22%. In the summer season, the larvae of Amphibalanus improvisus prevailed and in the autumn season the nauplii of Balanus rostratus prevailed. The number of larvae of barnacles was higher in Amursky Bay, with deep-sea species nauplii being concentrated in its central part and shallow water ones in the northern and central parts, in the zones of costal gyres. In Ussuriisky Bay, the density of larvae of most species decreased seaward from the coast. The abundance of larvae of invasive species A. improvisus show that it has successfully become naturalized in Amursky Bay and is gradually replacing the native species Chthamalus dalli and Balanus crenatus in the lower littoral and upper sublittoral zones.     

Taphonomy of acanthodians from the Devonian Bunga Beds (late Givetian/early Frasnian) of New South Wales

Several articulated, but incomplete, acanthodians from the Bunga Beds (late Givetian/early Frasnian) of the southern coast of New South Wales are tentatively identified as ischnacanthids. Heads are missing from all three prepared specimens. They exhibit the following characters: two dorsal fin spines; long, slender scapulocoracoids; slender, relatively deeply inserted, unpaired fin spines; minute scales with a fairly smooth, flat, crown; and an increase in size of normal body scales towards the tip of the tail. The fish are preserved in black, finely laminated shales, which were probably deposited as deep water, lacustrine sediments. The rarity, burial conditions, and headless state of the Bunga Beds acanthodians indicate that they might have died in shallow water, sunk to the bottom, refloated by gas‐induced buoyancy, with the heads lost while drifting out to deeper waters, where the bodies finally sank to a scavenger‐free, anaerobic substrate.     

The effects of exposure in sandy beach surf zones on larval fishes

The influence of wind and wave exposure on larval fish assemblages within a large bay system was investigated. Larval fishes were sampled from two areas with vastly different exposure to waves and wind, namely the windward and leeward sectors of Algoa Bay. In total, 5702 larval fishes were collected using a modified larval seine. Of these, 4391 were collected in the leeward and 1311 in the windward sector of the bay, representing a total of 23 families and 57 species. Dominant fish families included Clinidae, Engraulidae, Kyphosidae, Mugilidae, Soleidae and Sparidae, similar to the situation elsewhere, highlighting continuity in the composition of larval fish assemblages and the utilization of surf zones by a specific group of larval fishes. Nineteen estuary‐associated marine species occurred within the surf zones of Algoa Bay and dominated catches (86·7%) in terms of abundance. Postflexion larvae comprised > 80% of the catch, indicating the importance of the seemingly inhospitable surf zone environment for the early life stages of many fish species. The greatest species diversity was observed within the windward sector of the bay. Distance‐based linear modelling identified wave period as the environmental variable explaining the largest proportion of the significant variation in the larval fish assemblage. The physical disturbance generated by breaking waves could create a suitable environment for fish larvae, sheltered from predators and with an abundance of food resources.     

Seasonal variation of pelagic invertebrate larvae in the shallow antarctic waters of Admiralty Bay (King George Island)

Recent studies have revealed increasing numbers of benthic invertebrate species producing pelagic larvae in Antarctic waters. This paper investigates temporal changes in larval abundance in shallow areas of Admiralty Bay. Plankton was collected from December to May of 2000/2001 and 2001/2002. Air and water temperature and solar radiation were significantly higher during the second year, characterising three seasonal periods early summer, late summer and early winter. Mean meroplankton abundance was 160 and 1,548 in d.100 m⁻³ for the first and second years, respectively. Mollusc veligers were dominant in both years. Analysis of variance showed that in 2001 veligers were present in the early winter and in 2002 they were synchronous with the late summer phytoplankton bloom; polychaetes and trochophors were concentrated in the early winter, while echinoderms and nemerteans were abundant in early summer. These results showed the importance of seasonality (i.e. a combination of air and water temperature, solar radiation and food supply) to the reproductive events of an Antarctic coastal nearshore environment.     

New species of genera Tintinnopsis, Metacylis and Eutintinnus (Ciliophora, Spirotrichea, Tintinnida) from the Kuwaiti waters of the Arabian Gulf

The Kuwaiti waters occupy the northwestern part of the Arabian Gulf. These waters are shallow, well mixed, and characterized by a high level of biological productivity. Tintinnids form an important component of the microzooplankton community in Kuwaiti waters. They are particularly abundant in the northern waters of Kuwait, as well as in the waters of Kuwait Bay. However, the diversity of the tintinnid species has not been studied. Tintinnids were collected from Kuwaiti waters during a 1-year zooplankton survey, and tintinnid species were identified. In this paper four new species of tintinnids (Tintinnopsis failakkaensis, Metacylis pythos, Eutintinnus conicus, and E. contractus) are described from Kuwaiti waters. All these species occur commonly in these waters. Statistical comparative analysis is carried out on the basis of measurements taken from 400 specimens of tintinnids from Kuwaiti waters.