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Volume 46 (1999)
- Issue 2 Pages 75-
- Issue 1 Pages 1-
Volume 46, Issue 2
Displaying 1-9 of 9 articles from this issue
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Michiaki Tanaka1999 Volume 46 Issue 2 Pages 75-81
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSSeasonal changes in the loach population in different aquatic habitats surrounding paddy fields in Ehime Prefecture were investigated so as to establish the parameters necessary for stable propagation. Habitats were classified into three types: paddy fields, temporary creeks and permanent creeks. Adult or sub-adult loaches, which overwintered in the permanent creeks, entered paddy fields via temporary creeks at the beginning of the irrigation season. In the paddy fields, they spawned and reproduced until midseason drainage of the former. An increase in the number of juvenile loaches in the temporary creeks just before midseason drainage, indicated their having begun to disperse. During midseason drainage, the loaches moved primarily towards temporary and permanent creeks, seldom returning to the paddy fields. A survey of these habitats in autumn suggested that the species overwinters mainly in permanent creeks, the life cycle of loaches residing in habitats surrounding paddy fields, therefore being regulated by water-level control for agricultural purposes. The three habitats served different functions during the life cycle of the loaches, paddy fields being sites for reproduction, permanent creeks for overwintering and temporary creeks for dispersal.View full abstractDownload PDF (2930K) -
Shi Dong, Nobuhiko Taniguchi, Rikizo Ishida1999 Volume 46 Issue 2 Pages 83-90
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSLoaches, Misgurnus anguillicaudatus, collected from Torentsu river, Ibaraki, Japan, were found to comprise two types based on the morphological and genetic traits. Complete substitution of alleles of the two types at the AAT-2* and GPI-1* loci were found, as well as significant differences in allele frequencies at eight other loci. The genetic distance between the two types was 0.4. The belly color was yellowish in type I and grayish in type II, and the average number of precurrent rays was 21.4 (range: 16-25) and 10.5 (range: 7-13), respectively.
The results suggested that the two types should be regarded as a distinct biological species.View full abstractDownload PDF (4668K) -
Shigeo Harada, Izumi Kinoshita, Hiroaki Omi, Masaru Tanaka1999 Volume 46 Issue 2 Pages 91-99
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSTo clarify the early life history of Cottus kazika (Cottidae), we examined the distribution, migration, growth and food habit of larvae and juveniles collected by various methods from the Yura estuary and neighboring waters in western Wakasa Bay from November 1993 to May 1994, and from January to June 1995. Collections using an aqualamp in the rocky shore yielded mostly yolk-saclarvae, which tended to occur synchronously with the spring tide. This tendency was supported also by the back calculation of the hatching date estimated from otolith microstructural increments. Most of the larvae and juveniles were collected in the 5 m depth areas (mean salinity about 34 ppt) with a beam trawl (from 3.5 to 30m depth). We collected no C. kazika larvae and juveniles by oblique tows of alarva net in coastal areas of 10 to 50m depth. In wading areas of the surf zone, many larvae and juveniles were collected, particularly at the lowest salinity (mean about 26 ppt) station nearest to a river mouth. Mean size of larvae and juveniles were greater in the surf zone than in the 5 m depth areas. Food habits changed with growth, and differed between habitats. Pelagic larvae fed on copepods in 5m depth areas. Settled larvae and juveniles chiefly fed on mysids in 5 m depth areas, and gammarids in the wading areas of the surf zone. Thereafter, juveniles fed on tanaidaceans and trichopteran larvae in the estuary.View full abstractDownload PDF (3757K) -
Takeshi Kon, Tetsuo Yoshino1999 Volume 46 Issue 2 Pages 101-103
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSA specimen of Antennarius analis (Lophiiformes: Antennariidae), collected from Okinawa Island, Ryukyu Islands, Japan, represents the northernmost record of the species and the first record from Japanese waters. The species is easily distinguished from other members of the family in having the opercular opening adjacent to the anal fin. Judging from comments in the remarks accompanying the original description, the author of the species is Schultz, who was alone responsible for both the name and description of the species.View full abstractDownload PDF (2668K) -
Hisashi Imamura, Daiji Kitagawa1999 Volume 46 Issue 2 Pages 105-108
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSOn 15 April 1998, a single specimen of an agonid fish (153 mm SL, sex unknown) was collected from the western North Pacific, 37°59'N, 142°09'E (off Miyagi Pref., Honshu, Japan), at 700 m depth (3.4° bottom temperature).This specimen is identified with Bathyagonus nigripinnis Gilbert, owing to the agreement of following characters with diagnosis of the species: first preopercular spine with a supplementary spine, no barbels on mandible, lower jaw projecting forward beyond upper jaw, lachrymal with serrated ridge and margins, 45 lateral line plates and all fins being bluish black, although the minor differences, which can be regarded as the intraspecific variation, between present specimen and previous descriptions of B. nigripinnis were also recognized in the numbers of the dorsal fin ray, caudal fin ray and middorsal plate, and lengths of head and pectoral fin.This record represents a first occurrence of this species from Japan.View full abstractDownload PDF (2356K) -
Harumi Sakai, Yoshiki Tanaka, Hiroshi Tsujii, Akihisa Iwata, Itaru Ike ...1999 Volume 46 Issue 2 Pages 109-114
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDistribution pattern and introgression of two groups of Odontobutis obscura, West Seto and Hikimi Groups, around the Takatsu River were surveyed utilizing six diagnostic allozyme markers. West Seto Group fish were distributed to the middle to lower reaches of the Takatsu River and the upper reaches of the Abu River, while Hikimi Group fish occurred in the upper reaches of the Takatsu River, the Tama River and the Masuda River. West Seto Group population must have invaded the Takatsu River from the Abu River through presumed tributary exchanges between the upper reaches of the Abu River and the Tsuwano River, atributary of the Takatsu River. Slight accidental introgressions were recognized in two localities from Hikimi to West Seto Group populations. However, these two groups were distributed parapatrically and well isolated each other in the Takatsu River basin.View full abstractDownload PDF (626K) -
Kohji Mabuchi, Kazunori Matsumoto, Tetsuji Nakabo1999 Volume 46 Issue 2 Pages 115-119
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSA probable Pseudolabrus hybrid specimen, collected from Morode Beach on the Uwa Sea, Ehime Pref., Japan, in 1995, is the first report on natural hybridization in Pseudolabrus. The specimen had a color pattern on the dorsal surface of the head intermediate between that of Pseudolabrus eoethinus and P. sieboldi, and possessed a mosaic of character combinations: as in P eoethinus, the lowermost dark stripe behind the eye reached diagonally to the upper edge of the pectoral fin base; as in P sieboldi, the dorsal body surface (above the lateral line) had two rows of white spots. Principal component analysis based on six meristic and metric characters supported the likelihood of the specimen being intermediate between P eoethinus and P sieboldi.View full abstractDownload PDF (2176K) -
Takuya Kondou, Kazuhiro Sakata, Naohiko Takeshita, Akinobu Nakazono, S ...1999 Volume 46 Issue 2 Pages 121-125
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIwana-charr, Salvelinus leucomaenis is not indigenous to Kyushu Island western Japan. In 1971, this species was transplanted to a commercial hatchery by the Haki River (32°32'N, 130°57'E), a tributary of the upper reaches of the Kuma River System. Some of the charr individuals escaped from the hatchery's holding pond and came into the stream. Fifty-one were collected in the lower reaches near the hatchery but none in the upper reaches during 1994-1996. The collected sample consisted of individuals belonging to plural age classes. In addition, we observed some spawning activities of the charr in November every year during 1994-1997 and found some eggs in the redd. Our findings suggest that reproduction of the charr occurs in some tributaries of the upper reaches of the Kuma River and their distribution is expanding downstream. They also suggest that dams without fishways prevent the charr from migrating upstream.View full abstractDownload PDF (2349K) -
1999 Volume 46 Issue 2 Pages 139-144
Published: November 30, 1999
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1029K)
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