The rapid expansion of the dried sea cucumber market since the late 1980s has created a serious conservation issue worldwide. In fact, since 2002 sustainable use versus protection of sea cucumbers has been hotly debated at CITES meetings. In order to better understand the issue, this paper first explores the historical development of "sea cucumber foodways" in Asia. Only a few spiky sea cucumbers, among the 40 commercially traded species, are currently highly appreciated by Chinese gourmets. The second part of the paper introduces case studies of communal resource management based on my fieldwork on Rishiri Island, northernmost Japan, where the most expensive sea cucumbers with sharpest spikes in the world are harvested. In particular, I have focussed on: how the Rishiri sea cucumber fishery began, how a quality branding was achieved, and how resources are managed. Competing with strong market pressures and poaching, the fishermen of Rishiri Island have developed self-managed communal rules resulting from the exchange of ideas and practices with other societies.
In two fragmented small woods we assessed the overall distance traveled and the distances moved from the nest to nocturnal sites outside the nest by Pteromys volans orii. Records of the distances traveled per 30min showed that the Siberian flying squirrel moved significantly longer distances in the "after sun-set" period than in the "late night" period. Relatively short distance travelled in the "before sunrise" period suggested that the squirrel sometimes remained in one tree and foraged actively there during this period. Between the nest and nocturnal locations, males moved significantly greater distances than females in spring-autumn and winter. In both sexes, the distance traveled in winter was greater than that in spring-autumn, but the difference was not significant in females. Males moved longer distances to maintain their home ranges, which incorporated the home ranges of several females. Food resources were limited to a few tree species, and nests were limited to just a few cavities and dreys that provided good protection against low temperatures in winter. We suggest that the Siberian flying squirrel moves longer distances in winter because of the low numbers of food trees and winterproof nests. Females might gravitate all year towards nests that are more suitable for breeding and close to food resources; this may explain why the difference between the two seasons in the distances moved by females was obscure.
To investigate the effects of digestion by the Asiatic black bear Ursus thibetanus on seed germination, we conducted germination tests in the laboratory using Japanese bird cherry Prunus grayana (Rosaceae) seeds. We collected seeds from three different bird cherry trees (subsequently referred to as 'mother trees') between August 2006 and February 2007, and treated the seeds using four different methods: digested, extracted, juiced, and intact seeds. The single-factor ANOVA method was used for statistical analysis. In our study, seeds digested by bears showed higher rates of germination (89.0±11.0SD) than extracted seeds (66.7±8.9SD), while juiced seeds showed a lower rate of germination (10.2±4.5SD) and intact seeds did not germinate at all (0%). Our research also showed that the seeds taken from the three different mother trees did not differ significantly in their germination rates. The pulp juice and endocarp hinder the germination of the seeds of P. grayana. The difference between the germination rate of seeds that had passed through the alimentary canal of a bear and those that had their pulp removed manually was not clear; however, it seems likely that germination was improved by some mechanical or chemical aspect of passing through a bear's digestive tract.
Digestibility of food resources in Sika deer habitat were measured using in vitro methods using rumen inocula of deer and sheep or a cellulolitic enzyme. Experimental samples were collected both in warm temperate (150-900m above sea level) and cool temperate (900-1500m above sea level) zones in the mountainous of Tanzawa. A total of 150 test plants consisted of 39 samples of 38 species in summer and 111 samples of 65 species in winter. The test plants consisted of leaves and stems from forbs and grasses, leaves, dead leaves, twigs, and bark from evergreen or deciduous broadleaved shrubs and trees. Dry matter digestibility (DMD) measured by the two-step method (a series of incubations with rumen inocula and acidic pepsin solution) using rumen inocula of Sika deer ranged from 23.5% for leaf in Polygonum filiforme to 83.8% of leaf in Isopyrum stoloniferum in summer and from 0.3% of dead leaf in Fagus crenata to 76.6% of leaves in Cardamine flexuosa in winter. Compared with these results, DMD measured by the method using sheep rumen inocula was fitted for predicting in vitro DMD used deer rumen fluid and highly correlated with each pair of the values. DMD assayed by the enzymatic method, combining a series of incubations using the acid-pepsin treatment and cellulolitic digestion, was correlated with the samples collected in winter and in the cool temperate area in summer, but did not fit with the samples from the warm temperate area in summer. Our experimental results showed that in vitro methods using sheep rumen inocula are useful in predicting in vitro DMD of deer, and the enzymatic method is also able to measure DMD of food resources in winter deer habitat. The results are also available to evaluate the nutritive quality of plant resources eaten by free-ranging deer.
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