共查询到20条相似文献，搜索用时 234 毫秒
1.
白点鲑 (Ｓａｌｖｅｌｉｎｕｓｌｅｕｃｏｍａｅｎｉｓ)原产于日本 ,鲑科白点鲑属 ,可在水温 9～ 11℃的饲育条件下进行早期发育[1,2 ] 。有关白点鲑发眼卵贮运包装环境的温度、湿度、气体成分等因素对发眼卵生理、生态及运抵后孵化效果的影响 ,至今未见报道。 1996年 12月由中国水产科学研究院黑龙江水产研究所引进白点鲑发眼卵 ,并对其贮运条件及孵化条件进行研究 ,以确认高寒地区开发白点鲑属鱼类养殖的可行性 ,也为国内白点鲑发眼卵运输方式的改进提供技术依据。1 材料和方法1.1 发眼卵及其贮存1996年 10月在日本通过人工授精获得白点… 相似文献
2.
3.
4.
5.
6.
7.
8.
9.
黑龙江水产研究所承担的农业部重点科研项目《山女鳟引进驯化及养殖技术研究》经过二年的试验研究,已于1998年12月10日至11日在该所渤海冷水鱼试验站通过了由中国水产科学研究院副院长张荣权为组长的专家组验收,专家组对该项目研究取得的阶段性成果给予了充分肯定。 山女鳟是原产于日本山区河川的冷水性鲑科鱼类。其体态雍容,色彩典雅,肉质细嫩,品味鲜爽,自古就受到日本人民的珍爱。 相似文献
10.
黑龙江省水产技术考察团赴北海道考察报告金光铉，刘国兴，王雅春（宁安市虹鳟鱼开发总公司）（黑龙江省水产局科技处）根据黑龙江省与日本北海道之间的水产技术交流计划，为进一步学习考察日本虹鳟鱼三倍体育种新技术及鲑鳟鱼加工技术，我们主人组成黑龙江水产技术考察团... 相似文献
11.
Masatoshi Ban Hiroyuki Nagoya Shunpei Sato Hirohumi Yaegashi Masaki Ichimura Nobuhiro Sato 《Fisheries Science》2013,79(6):967-975
We evaluated the potential for hybridization between Atlantic salmon and salmonids currently present in Japan. We performed artificial and natural crosses and tested for hybridization using short interspersed elements. We documented the occurrence of hybrids and gynogenesis following artificial crossing. However, the survival rate of these offspring was low (<2 % to the fry stage). We were unable to obtain viable offspring from natural crosses of Atlantic salmon and chum salmon or masu salmon. Our results suggest that there is little risk of hybridization between Atlantic salmon and salmonids that are currently present in the wild in Japan. Furthermore, our results suggest that gynogenesis may occur naturally. 相似文献
12.
Abstract – The native and non-native freshwater fish species richness as well as the proportion of native fish species to overall fish species were examined to test a hypothesis of a spatial linkage between the distributions of dams and non-native fishes based on survey data collected in rivers and streams in Hokkaido, Japan. Non-native fish species have steadily increased in Hokkaido since the mid 1970s, as indicated by the decreasing proportion of native fish species per fish survey. Non-native species richness was significantly higher in areas above dams (i.e., reservoirs and their inlet streams) compared to areas without dams. As a result, the proportion of native fish species was lower above dams. This proportion was lower in developed and agricultural areas compared with forest areas, although both native and non-native species richness were higher in areas with development and agriculture. Non-native cyprinids, catfish and snakehead occurred primarily in a particular river basin with the largest drainage area, the longest history of reclamation and highest human population in the island. Non-native salmonids on the other hand, occurred in forest areas at higher elevations and their occurrence was associated with the existence of dams. There was a spatial linkage between the distribution of dams and non-native species, although it was applicable only to salmonids. The management of dams and reservoirs needs a strategy to prevent further expansion of exotic salmonids such as rainbow and brown trout. These species can be a significant threat to native Japanese salmonids as a result of various biological mechanisms. 相似文献
13.
Koh Hasegawa 《Ecology of Freshwater Fish》2020,29(3):419-428
Many species of salmonids have been stocked into waters outside of their native range. The invasiveness and impact of these species on native species varies depending on their biological traits, and on environmental conditions, such as climate. In Japan, rainbow trout and brown trout, both listed in 100 of the world's worst invasive alien species by the International Union for Conservation of Nature, occur as non-native species. The invasiveness of these two species is thought to be related to seasonal flooding, given flood waters can physically damage fry and prevent population establishment. Rainbow trout have successfully invaded waters in Hokkaido, northern Japan, where the likelihood of flooding is low between June and July, when their fry emerge, but successful invasions are rare in regions south of Hokkaido. Brown trout, however, have successfully invaded waters not only in Hokkaido, but also other regions. Since brown trout have a similar life history to the native white-spotted charr and masu salmon, with fry emerging before the flood season, they are more suited to the Japanese climate than Rainbow trout. Rainbow and brown trout interact with native species in various ways, but a common outcome of these interactions is the displacement of native charr species. Legal regulations of non-native salmonids should be based on understandings of the ecological traits of each invasive species and regional impacts on native species. Given the ongoing nature of climate change, the nature and extent of the effects of rainbow and brown trout on native species might also change. 相似文献
14.
Seasonal patterns of downstream movement in partially migratory stream‐dwelling Dolly Varden 
下载免费PDF全文
下载免费PDF全文 Christopher G. Ayer Hirotaka Katahira Sho Fukui Itsuro Koizumi 《Ecology of Freshwater Fish》2018,27(1):247-254
Migration is a common behaviour among salmonids, but not all individuals within a population migrate, instead becoming residents and remaining in their natal streams. This phenomenon, known as “partial migration,” is well studied among sea‐run and lake‐run populations; however, the lower migratory benefits and costs for mainstem‐run individuals question whether the same mechanisms can be applied for stream‐dwelling salmonids. In this study, we investigated main stem‐run timing and body condition of partially migratory stream‐dwelling Dolly Varden charr (Salvelinus malma) in the Shiisorapuchi River in central Hokkaido, Japan. Based on commonly observed patterns in sea‐run and lake‐run salmonids, we predicted that migration would occur during spring and consist predominantly of age 1 + females with some small subordinate males. Traps were placed at the mouths of two small tributaries along the Shiisorapuchi River periodically from May to December 2015. Adipose fin samples were taken for DNA to sex the individuals. Consistent to initial predictions, downstream movement occurs only once in the spring, dominated by age‐1 + females. Trapped fishes (presumed migrants) were slightly longer but slimmer compared to the fish caught in the tributaries (presumed resident), which may be equivalent to smolts in anadromous populations. Regardless of migratory habitat, mechanisms driving partial migration in salmonids may be the same as long as production between natal stream and feeding habitats is significantly different. 相似文献
15.
In northern Europe and America, the acidification of lakes and rivers induced by acid precipitation has damaged fish populations. At present, rapidly expanding industrial activities in East Asia have led to continuous increases in the quantity of emission of acidic pollutants, and rain of acidic levels of pH4 has precipitated throughout Japan. In this way, the effects of acid rain on fish populations have also been manifested in Japan. In order to examine the effects of low pH on the reproductive behavior of salmonids which are known to be acid-sensitive species, changes in the frequency of upstream behavior and spawning-related female nest-digging behavior in response to changes in pH were observed in mature hime salmon (land-locked sockeye salmon) Oncorhynchus nerka, brown trout Salmo trutta and Japanese char Salvelinus leucomaenis. Digging and upstream behavior were significantly inhibited in weakly acidic water of pH 5.8–6.4 formulated using sulfuric acid. Land-locked sockeye salmon was the most sensitive to changes in pH among the three species. 相似文献
16.
Diurnal variation in thermal environment experienced by salmonids in the North Pacific as indicated by data storage tags 总被引：2，自引：0，他引：2
Robert V. Walker Katherine W. Myers Nancy D. Davis Kerim Y. Aydin Kevin D. Friedland H. Richard Carlson George W. Boehlert Shigehiko Urawa Yasuhiro Ueno & Gen Anma 《Fisheries Oceanography》2000,9(2):171-186
Eight temperature-recording data storage tags were recovered from three salmonids in Alaska (pink and coho salmon and steelhead trout) and five chum salmon in Japan after 21–117 days, containing the first long-term records of ambient temperature from Pacific salmonids migrating at sea. Temperature data imply diel patterns of descents to deeper, cooler water and ascents to the surface. Fish were found at higher average temperatures at night, with narrower temperature ranges and fewer descents than during the day. Fish tagged in the Gulf of Alaska were at higher temperatures on average (10–12°C) than chum salmon tagged in the Bering Sea (8–10°C). Chum salmon were also found at a wider range of temperatures (−1–22°C vs 5–15°C). This is probably related both to the different oceanographic regions through which the fish migrated, as well as species differences in thermal range and vertical movements. Proportions of time that individual fish spent at different temperatures seemed to vary among oceanographic regions. Steelhead trout may descend to moderate depths (50 m) and not be limited to the top few metres, as had been believed. Japanese chum salmon may seek deep, cold waters as they encounter warm surface temperatures on their homeward migrations. Temperature data from all fish showed an initial period (4–21 days) of day and night temperatures near those of sea surface temperatures, suggesting a period of recuperation from tagging trauma. A period of tagging recuperation suggests that vertical movement data from short-term ultrasonic telemetry studies may not represent normal behaviour of fish. The considerable diurnal and shorter-term variation in ambient temperatures suggests that offshore ocean distribution may be linked more to prey distribution and foraging than to sea surface temperatures. 相似文献
17.
18.
Flavobacterium psychrophilum isolates, obtained from ayu, Plecoglossus altivelis, three species of salmonids and two species of cyprinids in Japan, were used in this study. Bacteria were inoculated to serum prepared from ayu or red spotted masu trout (RSMT), Oncorhynchus masou ishikawae, and incubated at 18 °C for 24 h. All isolates (n = 19) from ayu grew well with a 9- to 116-fold increase of CFU in ayu serum, while CFU decreased markedly in RSMT serum. In contrast, isolates (n = 17) from fish species other than ayu exhibited no growth in ayu serum, but some isolates from salmonids survived or grew (1.2-23.5 fold increase of CFU) in RSMT serum. The isolates that could not survive or grow in ayu and RSMT sera grew well in both heat-inactivated sera of ayu and RSMT. Experimental infection by intraperitoneal injection showed that ayu isolates examined were all pathogenic to ayu but not to RSMT, while none of the isolates from salmonids and cyprinids were pathogenic to ayu but some showed pathogenicity to RSMT. These results indicate that the in vitro growth ability of F. psychrophilum isolates in fish serum correlates well with their pathogenicity to fish, particularly in ayu. 相似文献
19.
After many technical measures and restocking activities in the River Rhine, there are now signs of salmonids being able to complete their anadromous life cycle. In Lake IJsselmeer, a former estuary of the River Rhine, the large effort associated with professional fisheries has been used to collect bycatch data on rare, migratory fish. To clarify the function of the lake for salmonids, catch data collected throughout the year between 1995 and 1999 were related to various possible migratory strategies known for these species. Species-specific differences were found in timing, length–frequency distribution and maturity stage reflecting different behaviour of Atlantic salmon, Salmo salar L. ( n =249) and sea trout, S. trutta L. ( n =3962). There was evidence that salmon exhibited traditional anadromous behaviour and use the lake only as a corridor. By contrast, sea trout appears to use the lake both as a corridor and as feeding habitat. 相似文献
20.
Water flow, volume discharge per unit time, is a master variable influencing much of the river environment and having profound effects on most of the biota, either directly or indirectly. Nevertheless, after decades of research and much accumulated knowledge, there remains much uncertainty about how to set environmental standards for flows that protect ecosystem components, including salmonids. This paper provides an overview of the findings of a conference on Flows and Salmonids. The aim of the conference and the papers that form this special issue is to update this information for salmonids, from which four key points are distilled that might influence future direction. (1) Fish responses to flow are very variable and flow effects are highly confounded with other related variables, which are often the proximate factors and need to be taken into account. (2) Meta‐analysis of previous studies has yet to be achieved because a hydromorphological template against which to gather and display such data has not yet been satisfactorily defined. (3) Some deviation from natural conditions may not necessarily be as detrimental for salmonids as sometimes stated. (4) Local investigations of flow impacts and solutions based on local conditions, and bringing in diverse disciplines and stakeholders, appear to offer the most pragmatic and effective approach to defining and implementing protective flows. Adaptive management offers a route for such collaborative studies, and its use is strongly encouraged. 相似文献