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Dao Ha Viet Takata Yoshinobu Omura Takuo Sato Shigeru Fukuyo Yasuwo Kodama Masaaki 《Fisheries Science》2009,75(2):507-512
Previously we reported that a significant level of domoic acid, a causative toxin for amnesic shellfish poisoning, was detected
in bivalves belonging to a genus Spondylus from various tropical Asian countries. These findings indicate that causative plankton species for domoic acid widely distribute
in these areas. In the present study, we monitored seasonal change of domoic acid level of Spondylus versicolor in association with that of plankton samples in Nha Phu Bay, Khanh Hoa, Vietnam from December 2004 to October 2005. The toxicity
of S. versicolor showed distinct seasonal variation. During the period when domoic acid level of S. versicolor was increasing, a significant level of domoic acid was detected in the plankton samples, showing the correlation between
these two parameters. These findings show that plankton causative for domoic acid occurred in the bay, and S. versicolor accumulate domoic acid during a bloom of the toxic plankton by food web transfer. 相似文献
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Thuy Linh Vu Yamamoto Shigeru Kawaura Rika Takemura Naoki Yamaki Kohei Yasumoto Ko Takada Kentaro Watabe Shugo Sato Shigeru 《Fisheries Science》2020,86(6):1101-1110
Fisheries Science - Pufferfish belonging to Lagocephalus are composed of several species, some of which have been recognized to be non-toxic. Although fish belonging to this genus inhabit a wide... 相似文献
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Kim Anh Thi Nguyen Chuong N.P.T. Bui Trang T. H. Le 《Aquaculture Economics & Management (Blackwell Science)》2016,20(1):82-108
Research results on the effects of aquaculture on poverty alleviation have been mixed. We use Tobit, simulation models and cross sectional survey data of 285 households, in Ben Tre Province, Vietnam, to evaluate the effects of aquaculture involvement on poverty, measured using per capita consumption of less than $1.25 USD, $1.50, and $2.00 per day. The results show for per capita consumption of less than $1.25 per day that households’ aquaculture participation or productivity had no or little effect on the living standard. For income levels above $1.25 per capita per day aquaculture participation or productivity influenced the standard of living. 相似文献
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Abstract – During 5–7 October 1999, 16 cichlids (30.5–51.0 cm) were tagged with radio transmitters in the Zambezi River in Namibia (eight threespot tilapia Oreochromis andersonii , seven pink happy Sargochromis giardi and one humpback largemouth Serranochromis altus ). The main objectives of this pilot study were 1) to assess whether and how telemetry can be used to follow the movements of larger cichlids in the upper Zambezi River and 2) to study the movements, habitat preferences and homing behavior of three cichlid species important for subsistence and trophy fishing during a period of increasing water flow towards the rainy period. Nine fish showed a downriver movement immediately after release, believed to be a behavioral response to catch and tagging. From 11 October, only small-scale movements were recorded. Average total distance moved from 11 October to 1 March was 375 m (range=1–1150) for threespot tilapia and 1276 m (range=540–1990) for pink happy. The farthest position compared to the position held on 11 October was on average 220 m away (range=0–500) for threespot tilapia and 538 m (range=20–1500) for pink happy. Displaced individuals did not show homing to the catch site. The threespot tilapia were, on average, located in the main river during 67% of the tracking surveys, in backwaters during 13% and in mouth of backwaters during 20%. The pink happy were, on average, located in the main river during 71% of the tracking surveys, in backwaters during 25% and in mouth of backwaters during 4%. 相似文献
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Sui Hyang Kuit Louisa Shobhini Ponnampalam Philip S. Hammond Ving Ching Chong Amy Yee-Hui Then 《水产资源保护:海洋与淡水生态系统》2021,31(11):3120-3132
- The paucity of baseline data on coastal cetaceans due to a lack of research in developing countries frequently precludes assessment of their status and informed management actions for conservation.
- This study provides the first abundance estimates of Indo-Pacific humpback dolphins, Irrawaddy dolphins, and Indo-Pacific finless porpoises in the coastal waters of Matang, Peninsular Malaysia.
- Boat-based surveys covering 1,152 km2 of coastal waters with 4,108 km of survey effort were conducted between 2013 and 2016 to collect data for line transect analysis of Irrawaddy dolphins and finless porpoises. Photo-identification data of humpback dolphins were concurrently collected for mark–recapture analysis.
- Estimates of abundance from four sampling strata totalled 763 Irrawaddy dolphins (CV = 13%, 95% confidence interval (CI) [588, 990]) and 600 Indo-Pacific finless porpoises (CV = 27%, 95% CI [354, 1,016]).
- The annual abundance estimates of humpback dolphins ranged between 171 (95% CI [148, 208]) in 2014–2015 and 81 (95% CI [67, 98]) in 2015–2016, likely due to the presence of offshore individuals that moved in and out of the study area. The estuarine strata were inhabited by 68 (95% CI [63, 73]) inshore humpback dolphins in 2013–2014 to 87 (95% CI [78, 97]) dolphins in 2014–2015.
- As an International Union for Conservation of Nature important marine mammal area, the productive coastal waters of Matang are shown to support a high density of small coastal cetaceans, and the results serve as an important baseline for future studies to identify population trends for conservation management plans.
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Proliferative kidney disease (PKD), caused by the myxozoan endoparasite Tetracapsuloides bryosalmonae, is of serious ecological and economical concern to wild and farmed salmonids. Wild salmonid populations have declined due to PKD, primarily in rivers, in Europe and North America. Deep lakes are also important habitats for salmonids, and this work aimed to investigate parasite presence in five deep Norwegian lakes. Kidney samples from three salmonid species from deep lakes were collected and tested using real-time PCR to detect PKD parasite presence. We present the first detection of T. bryosalmonae in European whitefish in Norway for the first time, as well as the first published documentation of the parasite in kidneys of Arctic charr, brown trout and whitefish in four lakes. The observed prevalence of the parasite was higher in populations of brown trout than of Arctic charr and whitefish. The parasite was detected in farmed, but not in wild, charr in one lake. This suggests a possible link with a depth of fish habitat and fewer T. bryosalmonae-infected and PKD-affected fish. Towards a warmer climate, cold hypolimnion in deep lakes may act as a refuge for wild salmonids, while cold deep water may be used to control PKD in farmed salmonids. 相似文献
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Yan Tan Kiyoshi Osatomi Yukinori Nozaki Tadashi Ishihara Kenji Hara 《Fisheries Science》2006,72(1):185-194
ABSTRACT: We purified cathepsins B1 and B2 from the ordinary muscle of carp Cyprinus carpio . The N-terminal amino acid sequences (12 residues) of 29 kDa bands of cathepsins B1 and B2 are the same and showed high homology of 75% and 83%, respectively, with the heavy chain of rat and human cathepsins B. Based on conserved sequences of other cathepsins B and the N-terminal amino acid sequences of 29 kDa bands, we cloned carp cathepsin B cDNA. The nucleotide sequence of carp cathepsin B cDNA consists of 1470 bp including a 993 bp open reading frame, encoding a deduced protein of 330 amino acids. The deduced amino acid sequence of carp cathepsin B has similarity of 80% to rainbow trout cathepsin B and of 76–78% to other vertebrate cathepsins B. The sequence of its isoform was also determined during molecular cloning, which has 94.8% similarity with first cloned cathepsin B. They are completely same in N-terminal amino acid sequence of heavy chain, active site and potential N-glycosylation site. This indicates there are at least two kinds of cathepsin B functioning in vivo in carp. 相似文献
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In this paper the results of a study conducted on the culture‐based fisheries in small (ranging from 2 to 160 ha), farmer‐managed reservoirs in YenBai and ThaiNguyen Provinces in the northern highland region of Vietnam, for the production cycles of 1997/98, 98/99 and 99/00 are presented. The small reservoirs are leased to small farmers by the provincial authorities for fishery activities, and all lessees adopt culture‐based fisheries when fingerlings of grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), common carp (Cyprinus carpio) and mrigal (Cirrihinus mrigala) are stocked between March and mid‐April each year and harvested, using large seine nets, after approximately 11–12 months. The mean yields from reservoirs in YenBai and ThaiNguyen Provinces in 97/98, 98/99 and 99/00 production cycles were 251, 332 and 253, and 331, 372 and 210 kg ha?1 respectively. There were major differences in the fish productivity in the reservoirs in the two Provinces, and in a reservoir between culture cycles. The stocking strategies appeared to be rather ad hoc, being determined by the availability of seed stock and the financial status of the lessees. Accordingly, there was no apparent consistent trend in the improvement of yields from the culture‐based fishery practice throughout the growth cycles. The fish yields in reservoirs in each Province were significantly related to reservoir area (exponentially) and to mean weight of stocked fish and conductivity (logarithmically). Of the stocked fish, the highest returns were obtained with mrigal and bighead carp, which collectively contributed > 50% to the harvest. The return from common carp was the lowest. The mean growth rate of grass carp (2.7 g day?1), followed by bighead carp (2.0 g day?1) was the highest in reservoirs in YenBai Province, bighead carp (4.0 g day?1) followed by grass carp (3.2 g day?1) was the highest in ThaiNguyen Province. The seed stocked on average accounted for 65% and 48% of the total operating costs in YenBai and ThaiNguyen Provinces, and the mean cost:benefit ratio of the culture‐based fishery in the two Provinces was 0.35 and 0.37 respectively. The culture‐based fishery on average contributed about 28% to the gross income of a farmer lessee. 相似文献
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Hai Son Nguyen Anh T Bui Dieu Q Nguyen Dung Q Truong Luu Thanh Le Nigel W Abery & Sena S De Silva 《Aquaculture Research》2005,36(11):1037-1048
This study was conducted in 20 reservoirs, ranging in size from 4 to 30 ha, in the mountainous, northern region of Vietnam, in ThaiNguyen and YenBai provinces, over two growth cycles in 2002/03 and 2003/04. The reservoirs are leased by farmers for fishery activities from the provincial administration, and the trials were managed by the lessee farmers. Three species combinations in ratios (by fingerling weight) of grass carp: silver carp: bighead carp: common carp: mrigal 1:2:1:1:3 (A), 1:3:1:1:2 (B) and 1:2:1:1:2 (C) were used as seed stock. The overall mean yield of stocked fish in 2002/03 and 2003/04 growth cycles in reservoirs in ThaiNguyen and YenBai provinces was 165 (±21) and 190 (39), and 287 (±22) and 325 (±24) kg ha?1 respectively. The yield in reservoirs in both provinces, in both growth cycles and irrespective of the species combinations, increased in relation to stocking density. In reservoirs in ThaiNguyen Province, the species combination B gave the lowest yield (both growth cycles and overall), and differed significantly (P<0.05) from combinations A and C. The stocking efficiency (ratio of the yield of stocked fish in kg ha?1 to the weight of the stocked fish in kg ha?1) in reservoirs in ThaiNguyen Province ranged from 2.9 to 5.1 over the two growth cycles and that in YenBai from 2.8 to 3.9. There was no discernible trend between growth cycles and/or between species combinations. The major cost incurred was for fingerling procurement. In all instances, a net profit was accrued. The mean (±standard error (SE)) net profit ha?1 (in 103VN dong; approximately 15 500 VND=1 US$) was 885 (±270) and 864 (±214), and 1322 (±176) and 1600 (±150) for the growth cycles 2002/03 and 2003/04 for reservoirs in ThaiNguyen and YenBai provinces respectively. Between the two growth cycles, the net profit increased in eight and three reservoirs from YenBai and ThaiNguyen, respectively, the maximum increase being recorded in Khuan Gio (165%) and Dong Man (39%) reservoirs. 相似文献
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S. E. Shumway T. L. Cucci M. P. Lesser N. Bourne B. Bunting 《Aquaculture International》1997,5(1):89-99
Juvenile scallops (<2 mm shell height) of three species (Placopecten magellanicus, Patinopecten yessoensis, Argopecten irradians) were fed mixed, unialgal cultures. Scallops were fed a total of six algal clones simultaneously and clearance rates were
monitored using flow cytometric techniques. In another experiment, scallops were presented with natural assemblages of particulate
matter as a food source. Data are presented on differences in clearance rates for the individual algal species as well as
size-related differences of algal clones, and uptake of chlorophyll vs. non-chlorophyll cells, both within and between scallop
species. Significant differences in clearance rates of individual algal species have been found within and between scallop
species. Particle selection does not appear to be based upon size alone and is apparently based on other characteristics of
the algae as well. The results demonstrate pre-ingestive sorting. 相似文献
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Thi Thu Hang Ngo Hossein Azadi Huu Cuong Tran Philippe Lebailly 《Aquaculture International》2018,26(2):451-468
Clam farmers have experienced different types of risks that have been further exacerbated by the rapid expansion of clam farming areas, increased growing densities, and increased market difficulties in recent years in the Thaibinh Province of Vietnam. Most farmers have been seriously affected by production risk, market risk, and financial risk, while a number of others have met with success in almost all of their clam-raising cycles. This study applied a differentiating comparative analysis method and multiple discriminant analysis method to discuss the differences in risk management strategies between and among clam farming households and the impacts of those differences on their success/failure rates. In general, the tactics are related to increase in farm size, the application of technical innovations, diversifying livelihood activities, and accessing secure financial sources all provided better conditions for clam growth, diminished losses, and led to speedier recovery from shocks. To support farmers in managing risks, several government interventions are needed: (1) better re-zoning of clam farming areas in parallel with an increase in the farm size of each household, (2) promoting sustainable linkages between the farmers and the formal financial market and output market, and (3) investing more funding into research and extension related to sustainable clam farming practices and to the improvement of farmers’ skills in cooperative works and management. 相似文献
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水产品中河鲀毒素的高效液相紫外测定法 总被引:1,自引:0,他引:1
以鲀科鱼类为研究材料,采用超声波法提取,C18-WCX联用固相萃取纯化,使用高效液相色谱紫外检测方法测定水产品中河鲀毒素含量,通过探索提取方法和色谱条件对检测结果的影响,并确定和优化色谱分离和紫外检测条件,建立了一种高效液相紫外检测测定水产品中河鲀毒素的方法。该检测方法稳定性好,可操作性强,加标回收率在75%~82%之间,相对标准偏差小于15%,检出限达到0.02mg/kg。与现行河鲀毒素检测方法相比,该方法具有对仪器要求低、操作简便的特点,易于推广应用。 相似文献
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Abstract – The reproductive biology of three species of rainbowfish (Melanotaeniidae) in northeastern Australian rainforest streams was investigated. Two species, Melanotaenia eachamensis and Cairnsichthys rhombosomoides are endemic to the area, whereas the third, M. splendida splendida, is more widespread. The species were all highly fecund, producing many hundreds of eggs between 1.10 and 1.24 mm in diameter. Melanotaenia eachamensis was the most fecund, produced the largest eggs of the three species, and consequently exhibited the greatest maternal investment (as measured by gonadosomatic index). The majority of reproductive effort occurred during the dry season, although reproductively active fish were present year-round for each of the species, but particularly so for M. s. splendida and C. rhombosomoides. No evidence for a role by temperature or photoperiod as environmental cues for reproduction was found, and it was suggested that gonad development was strongly tied to somatic growth. The concentration of reproduction to the dry season ensures that larvae are produced during a period of relatively stable and benign physical conditions. Comparison of temporal changes in gonadosomatic index values suggest that the spawning season of M. eachamensis , which occurs in high-elevation streams, is more restricted and commences about 1 month earlier than either other species. A similar phenology was observed for the M. s. splendida population found at high elevation and highlights the potential for spatial differences in stream productivity to influence life history. Note 相似文献
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为研究和控制野生鸟类传播禽流感,对山西省鸟类分布情况进行了研究和分析。山西省鸟类物种记录为335种,大约有12.3%的鸟生活在村落附近,10.3%的鸟类生活在农田、水田附近,12.8%的鸟类生活在水域周围,23.5%的鸟类出现在灌木草丛附近,这些鸟类均可与家禽及人类接触,从而传播禽流感病毒;其余41.1%的鸟类生活在山林、悬崖、树林等与家禽接触不到的地方。 相似文献