Shiretoko Nature Foundation

Shari, Japan

Shiretoko Nature Foundation

Shari, Japan
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Azuma N.,Hokkaido University | Zaslavskaya N.I.,RAS A.V. Zhirmunsky Institute of Marine Biology | Yamazaki T.,Shellfish Museum of Rankoshi | Nobetsu T.,Shiretoko Nature Foundation | Chiba S.,Tokyo University of Agriculture
Genetica | Year: 2017

We investigated genetic diversity and population structure of the Sitka periwinkle Littorina sitkana along the coastlines of the northwestern Pacific (NWP) to evaluate the possibility of trans-Pacific colonization of this species from the NWP to the northeastern Pacific (NEP) after the Last Glacial Maximum. We sampled L. sitkana from 32 populations in the NWP, and sequenced a region of the mitochondrial cytochrome b oxidase gene for population genetic analyses. The results were compared with those of previous reports from the NEP. The genetic diversity of L. sitkana was much higher in the NWP than in the NEP. Genetic connectivity between the NWP and NEP populations was indicated by an extremely abundant haplotype in the NEP that was also present in eastern Hokkaido and the Kuril Islands. To confirm these results, we compared sequences of the longest intron of the aminopeptidase N gene (APN54) in the nuclear genome in four populations of L. sitkana in the NWP with previous results from the NEP. Again, much higher genetic diversity was found in the NWP than in the NEP and genetic connectivity was supported between the Kuril Islands and the NEP. These results imply postglacial colonization of this species from the NWP to the NEP, probably along the Kuril and Aleutian Island chains. This study is the first report of possible trans-Pacific postglacial colonization of a direct-developing gastropod, inferred from genetic data. © 2017 Springer International Publishing Switzerland


Kohira M.,Shiretoko Nature Foundation | Mori S.-Y.,Shiretoko Raptor Society
Ursus | Year: 2010

We describe an incident we investigated in which a photographer on the Shiretoko Peninsula, Hokkaido, Japan observed a pair of adult brown bears (Ursus arctos yesoensis) mating on 11 October 2009. After an interview and examination of photographs, we conclude that the mating did occur on the reported date. Copulation evidently lasted about 30 minutes without overt struggle either before or after the event. Several days prior to the date, a female, which we presume to be the one involved, was seen with swollen and colored genitalia, suggesting she was in estrus. Only a single mating was witnessed and neither of the bears was observed after this date. Throughout its range, mating of brown bear is rarely observed in autumn, and this is probably the first record in Hokkaido. © 2010 International Association for Bear Research and Management.


Arima D.,Hokkaido University | Yamaguchi A.,Hokkaido University | Nobetsu T.,Shiretoko Nature Foundation | Imai I.,Hokkaido University
Crustaceana | Year: 2016

In the Okhotsk Sea, the calanoid copepod Metridia okhotensis Brodsky, 1950 is the dominant component of zooplankton, accounting for 61% of the annual mean total pelagic copepods. Although this organism is important, little ecological information is available for M. okhotensis in the Okhotsk Sea because of the ice cover during winter, which prevents the collection of seasonal samples in this region. Here, we report the seasonal changes in the population structure, sex ratio and female gonad maturation of M. okhotensis. The data are from samples collected using water pumped from a depth of 350 m off Rausu Harbour in the Okhotsk Sea at 2-week intervals over a 2.5-year period. Due to the mesh size of the strainer (420 μm), M. okhotensis was collected from C3 to adults. The sex ratio of C5 (female :male) was approximately 1 : 1 throughout the year. In contrast, the sex ratio of C6 (adult) showed a clear seasonality, with males (C6M) occurring only from December to May and females (C6F) dominating during the other seasons. The gonad maturation of C6F was scored using five categories, and their composition also showed clear seasonality. From January to April, gonads developed rapidly from stage I (immature) to V (spawning). During the other seasons, the majority of C6F had immature gonads. Based on these data, we conclude that this species likely has a diapause phase for C6F, with immature gonads, and C5M from June to November. Moulting from C5M to C6M began in December. Accompanying the occurrence of C6M, C6F were fertilized from December to January. C6F underwent gonad maturation from January to April and performed primary reproduction from April to May. Thereafter, M. okhotensis entered diapause from June to November. © Koninklijke Brill NV, Leiden, 2016.


Bower J.R.,Hokkaido University | Seki K.,Shiretoko Diving Kikaku | Kubodera T.,National Museum of Science and Nature | Yamamoto J.,Hokkaido University | Nobetsu T.,Shiretoko Nature Foundation
Biological Bulletin | Year: 2012

Brooding of egg masses by a squid in Japan is described. Brooding females were photographed in situ, and the females, their eggs, and their hatchlings were collected. The squid had all undergone gelatinous degeneration and swam slowly and continuously by undulating the fins and expelling water sporadically through the funnel. Eggs were held together by a dark, viscous material that formed a singlelayer, sheet-like mass, from which hatchlings were seen to emerge. The annual appearance of brooding females in surface waters during spring suggests that they transport their egg masses from deep water to the surface before the eggs hatch. Genetic analyses identified the squid as Gonatus madokai (family Gonatidae), now the second gonatid and third squid known to brood. © 2012 Marine Biological Laboratory.


Arima D.,Hokkaido University | Matsuno K.,Arctic Environmental Research Center | Yamaguchi A.,Hokkaido University | Nobetsu T.,Shiretoko Nature Foundation | Imai I.,Hokkaido University
Crustaceana | Year: 2015

The seasonal and inter-annual changes in the asymmetry of female insemination and the male leg 5 of the planktonic calanoid copepods Metridia okhotensis and M. pacifica were investigated in the Okhotsk Sea. An inter-species comparison of both parameters was also carried out on seven Metridia species collected from oceans throughout the world. For M. okhotensis from the Okhotsk Sea, most of the females showed left-side insemination (annual average: 95.7%) and most of the males showed left-side asymmetry (99.7%) of the long inner process of the second exopodal segment in the fifth leg throughout the year. However, sympatric M. pacifica showed different ratios of asymmetry for female insemination and male morphotypes with a left : right = 1 : 2 ratio throughout the year. For the seven Metridia species from the global oceans treated in this study, ratios of asymmetry for female insemination and male morphotypes were correlated with each other. One-sided insemination (i.e., only left or only right insemination) was a common pattern for various Metridia species from global oceans, but their ratios varied by species. Previously, low hatching rates (29-68%) of eggs were reported for various Metridia spp. in laboratory experiments, but the reasons for these low rates were unclear. Because each spermatheca of Metridia spp. is connected to the oviduct on the same side, either left or right, this suggests that half of the eggs produced by unilaterally inseminated females remain unfertilized. The morphology of the genital structures and literature data of the egg hatching rates of Metridia spp. indicate that almost half of the eggs produced by females are not viable and are, thus, wasted. © Koninklijke Brill NV, Leiden, 2015.


Koike S.,Tokyo University of Agriculture and Technology | Masaki T.,Tokyo University of Agriculture and Technology | Masaki T.,Japan Forestry and Forest Products Research Institute | Nemoto Y.,Tokyo University of Agriculture and Technology | And 7 more authors.
Oikos | Year: 2011

We estimated the seed shadow created by the Asiatic black bear Ursus thibetanus in order to evaluate the bears effectiveness as a seed disperser. We combined data from bear movements, determined by GPS telemetry, with data from gut retention time (GRT). We estimated plant seed shadows in two ways: from direct movement data to give the actual seed shadow (ASS), and from cumulative movement data to give the potential seed shadow (PSS). The purpose of this study was to answer the following questions: (1) does GRT differ between seasons or in the size of contents? (2) Does seed shadow vary among sex, seasons, estimation method (ASS or PSS), and years? (3) Does the masting affect seed shadows? There were no differences in median GRT among seasons or seed dimensions. Combining these data, the seed shadows produced by long GRT (median; 15.2-19.7 hours, maximum; 44.0 hours) and large daily movements suggest that the bears effectively move 40% of the seeds they consume to a distance greater than 500 m from the parent tree and can potentially move the seeds up to a maximum distance of more than 22 000 m from the parent tree. The results also indicate that bears make complex seed shadows caused by multiple defecations and long periods of daily movement. In summary, PSS did not differ between sexes, but PSS can be expected to be larger in autumn than in summer of each year. ASS, however, can be expected to be larger in males than females, and to be larger in autumn than in summer. ASS may become especially large during a poor masting year as compared to good masting years. These results indicate that bears are potentially more effective seed dispersers during years of poor fruit production in autumn. The bears have longer seed shadows than other seed disperser and consequently may play a unique role in the maintenance and renewal of forest ecosystem. © 2011 The Authors.


Yamamura O.,Hokkaido National Fisheries Research Institute | Nobetsu T.,Shiretoko Nature Foundation
Journal of the Marine Biological Association of the United Kingdom | Year: 2012

Food habits of threadfin hakeling Laemonema longipes, the dominant demersal fish in the upper continental slope of the western sub-Arctic North Pacific, were described based upon >1400 specimens collected off north-eastern Honshu Island and south-eastern Hokkaido Island, Japan. Threadfin hakeling depended exclusively on pelagic organisms including copepods Neocalanus cristatus, Euphausia pacifica, shrimps Sergestes similis, firefly squid Watasenia scintillans and myctophids Diaphus theta. Threadfin hakeling showed a clear size-dependent dietary variation, with mesozooplankton and shrimps being important for small-and medium-sized fish (≤400 mm standard length (SL)), and myctophids being important for large-sized fish (>400 mm SL). Since all of these prey undertake diurnal vertical migration, it was concluded that threadfin hakeling take an important role in capturing energy and materials transported from the epipelagic zone to the bathypelagic layer over the upper continental slope. Dietary variation among different areas, seasons and depths were also examined. Of these, areal difference was rather obscure reflecting common prey field in the Tohoku and Doto areas under the prevalence of the North Pacific Intermediate Water, whereas clear seasonal difference was found in the Doto area; the 0-group of walleye pollock Theragra chalcogramma was ingested only in the late summer and early autumn in this area. © 2011 Marine Biological Association of the United Kingdom.


Kubo K.,Hokkaido University | Yamaguchi K.,Japan Institute for Environmental Sciences | Ishinazaka T.,Shiretoko Nature Foundation | Yamada W.,Hokkaido University | And 2 more authors.
Marine Pollution Bulletin | Year: 2014

The concentrations of PCB congeners in the blubber and liver of mother Steller sea lions (Eumetopias jubatus; SSLs) and their fetuses from the coast of Hokkaido, Japan in 2008, 2010 and 2012 were analyzed by HRGC-HRMS, in order to elucidate PCB congener profiles and maternal-to-fetal transfer of PCBs in SSLs. σPCBs in the fetuses were 1400. ± 660 (the mean ± SD) ng/g-fat in the blubber and 570 ± 320 ng/g-fat in the liver, respectively. There was a concern that SSLs had been contaminated by PCBs during the fetal period. The concentrations of the major congeners in the blubber and liver were a correlation between the fetus and mother (blubber: r= 0.9934, liver: r= 0.9160; P≤ 0.05). The results indicated that PCBs in the fetuses came from the mothers. #177 and #199 showed no correlations between the fetus and the mother in the blubber and liver. This indicated a selective capture by some natural protector such as the placenta. © 2013 Elsevier Ltd.


Minami K.,Hokkaido University | Minami K.,Kyoto University | Yasuma H.,Forestry and Fisheries Technology Center | Tojo N.,Hokkaido University | And 4 more authors.
Fisheries Science | Year: 2010

Sustainable management of the kelp forests of the Shiretoko Peninsula, a World Natural Heritage site, is necessary due to kelp's ecological and economic importance. The objectives of this study were to estimate the area of kelp forests and to clarify their spatial characteristics in coastal waters of the Shiretoko Peninsula. Data on the presence/absence and thickness of kelp forests were collected via acoustic observation on transects over about 80 km using an echosounder at 200 kHz. Acoustic data were geostatistically interpolated, and the areas covered by kelp forests were estimated. Differences in kelp distribution between the eastern and western sides of the peninsula were compared. The total area of kelp forest was 3.88 km2 (eastern area: 3.49 km2; western area: 0.39 km2). The range of thickness of the kelp forests was 34-91 cm. Many kelp forests in the eastern area were thick (>78 cm) and distributed continuously, while kelp forests in the western area were sparsely distributed. © 2010 The Japanese Society of Fisheries Science.


PubMed | Shiretoko Nature Foundation, Hokkaido National Fisheries Research Institute, Japan Institute for Environmental Sciences and Hokkaido University
Type: Journal Article | Journal: Marine pollution bulletin | Year: 2014

The concentrations of PCB congeners in the blubber and liver of mother Steller sea lions (Eumetopias jubatus; SSLs) and their fetuses from the coast of Hokkaido, Japan in 2008, 2010 and 2012 were analyzed by HRGC-HRMS, in order to elucidate PCB congener profiles and maternal-to-fetal transfer of PCBs in SSLs. PCBs in the fetuses were 1400 660 (the mean SD) ng/g-fat in the blubber and 570 320 ng/g-fat in the liver, respectively. There was a concern that SSLs had been contaminated by PCBs during the fetal period. The concentrations of the major congeners in the blubber and liver were a correlation between the fetus and mother (blubber: r=0.9934, liver: r=0.9160; P 0.05). The results indicated that PCBs in the fetuses came from the mothers. #177 and #199 showed no correlations between the fetus and the mother in the blubber and liver. This indicated a selective capture by some natural protector such as the placenta.

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