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Spacing and kinship of the Formosan squirrel, Callosciurus erythraeus thaiwanensis, were studied in two different habitats. One, native habitat in the woods of Kenting, southern Formosa, was rich in available food throughout the year and had several species of predators. The other, a site in Kamakura, central Japan where squirrels had been introduced, had(More)
Recent studies in streams and ponds have demonstrated that the distribution and biomass of aquatic organisms can be estimated by detection and quantification of environmental DNA (eDNA). In more open systems such as seas, it is not evident whether eDNA can represent the distribution and biomass of aquatic organisms because various environmental factors(More)
We examined factors affecting the vertical distribution of juvenile walleye pollock during “the second critical period” (i.e. the transition period of prey size) in and around Funka Bay, Hokkaido, Japan. During the day, small juveniles (<30 mm) were distributed mainly in shallow, warm, and low-salinity water within the bay, whereas larger ones (≥30 mm)(More)
The southwestern Pacific coast of Hokkaido is the main spawning ground for the Japanese Pacific stock of walleye pollock Theragra chalcogramma. A commercial gillnet fishery targeting spawning adult pollock in this area mainly operates from October to January to coincide with the migration of adult pollock from the feeding ground. Given the results of(More)
The behavior of endangered adult Sakhalin taimen Parahucho perryi was tracked during 2008–2010 using acoustic telemetry in the Bekanbeushi River system, which flows through eastern Hokkaido, Japan. Movement distances per unit time of tracked P. perryi were compared between mid- and downstream habitats. Results indicated that movement distances were(More)
The images for Figs 2 and 3 are incorrectly switched. The image that appears as Fig 2 should be Fig 3, and the image that appears as Fig 3 should be Fig 2. The figure captions appear in the correct order. access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in(More)
The target strength (TS) patterns of Sardina pilchardus and Sardinella aurita at 38 and 120 kHz were estimated by a prolate-spheroid model, using measurements of swimbladder length and width. The ratio of swimbladder length to total length (TL) was similar in both species, however the ratio of swimbladder width to TL was smaller and more variable for S.(More)
Behavior of adult Parahucho perryi was examined using bio-logging and acoustic telemetry concurrently in the Bekanbeushi River system, eastern Hokkaido, Japan, in 2009 and 2010. Based on 46.1–87.9 h data from five P. perryi (69.0–80.0 cm fork length) caught from Lake Akkeshi, they used upstream (n = 2), midstream (n = 3), and downstream (n = 4) habitats.(More)
Eelgrass beds are an important source of primary production in coastal ecosystems. Understanding seasonal variation in the abundance and distribution of eelgrass is important for conservation, and the objectives of this study were to 1) monitor seasonal variation in eelgrass beds using an acoustic monitoring method (Quantitative echo sounder) and 2) broadly(More)
The sexual maturation process and reproductive biology of female Arabesque greenling Pleurogrammus azonus in the Sea of Japan, off the west coast of Hokkaido, was examined using histological observations of ovaries. Maturation of P. azonus was classified into seven phases based on the presence of nine oocyte stages, post ovulatory follicles, and residual(More)