Seasonal variation of domoic acid in a bivalve Spondylus versicolor in association with that in plankton samples in Nha Phu Bay,Khanh Hoa,Vietnam

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.     

Tissue distribution of tetrodotoxin and its analogs in Lagocephalus pufferfish collected in Vietnam

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...     

Aquaculture and poverty alleviation in Ben Tre Province,Vietnam

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.     

大连沿海织纹螺属Nassarius(腹足纲,织纹螺科)三种新记录种

在整理分类近年来大连沿海采集的织纹螺科标本时,鉴定出属于织纹螺属的3个大连沿海新记录种:半褶织纹螺 Nassarius sinarus (Phillippi,1851)、群栖织纹螺 Nassarius gregarius (Grabau & king,1928)和胆形织纹螺 Nassarius pullus (Linnaeus,1785)。它们主要生活在潮间带及浅海或稍深的沙质、泥沙、软泥或岩礁质海底。     

Movements and habitat utilization of three cichlid species in the Zambezi River, Namibia

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%.     

Abundance estimates of three cetacean species in the coastal waters of Matang,Perak, Peninsular Malaysia

1. 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.
2. 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.
3. 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.
4. 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]).
5. 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.
6. 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.

     

草鱼“三病”发病规律及防治措施

草鱼"三病"是指草鱼细菌性烂鳃、细菌性肠炎以及赤皮病这三种病.这三种病是草鱼的主要暴发性疾病,各种规格的草鱼都可发病,所造成的经济损失也是居草鱼疾病之首,夏季为了有效做好这三种疾病的防治工作,现将其发病规律、诊断要点以及防治方法与措施作一介绍,以供参考.     

Patterns of Tetracapsuloides bryosalmonae infection of three salmonid species in large,deep Norwegian lakes

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.     

Occurrence of two distinct molecular species of cathepsin B in carp Cyprinus carpio

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.     

陕西省当前猪病发生特点、流行趋势及防控对策

目前陕西省养猪业发展迅速,但是由于对猪病缺乏有效的防控手段,致使猪病种类繁多难以控制,给陕西养猪业造成重大的经济损失。从陕西省常见猪病的分类、猪病的流行现状、猪病流行的原因分析、猪病防控对策等4个方面综述了陕西省当前猪病防控存在的问题及如何控制猪病的发生,为陕西省猪病的防控提供参考资料。     

The culture-based fisheries in small, farmer-managed reservoirs in two Provinces of northern Vietnam: an evaluation based on three production cycles

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.     

Culture-based fisheries in small reservoirs in northern Vietnam: effect of stocking density and species combinations

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.     

Particle clearance and selection in three species of juvenile scallops

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.     

织纹螺的生物学特征及毒性分析研究进展

正织纹螺(Nassarius),俗称麦螺、白螺、海丝螺、海蛳螺、割香螺、甲锥螺,是织纹螺科所有种类的统称,属软体动物门、腹足纲、前鳃亚纲、新腹足目、蛾螺总科[1-2],喜欢生活在柔软的底质上,适应能力很强,遍布于世界各海区。据不完全统计,全球共有织纹螺286种[3]。织纹螺味道鲜美,是包括我国在     

Assessment of household risk management strategies for coastal aquaculture: the case of clam farming in Thaibinh Province,Vietnam

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.     

水产品中河鲀毒素的高效液相紫外测定法

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。     

免疫荧光层析快速检测河豚毒素的研究

本研究利用自制的河豚毒素荧光免疫层析检测卡对河豚毒素进行快速定量检测,并分析其稳定性、灵敏度、趋势线拟合程度及检测范围。研究结果表明,自制的河豚毒素荧光免疫层析检测卡变异系数为0.124,拟合方程相关系数r~2值为0.995 5,检测卡的检测范围为2~600 ng/m L,可以满足对河豚毒素快速定量检测的要求。     

Reproduction in three species of rainbowfish (Melanotaeniidae) from rainforest streams in northern Queensland, Australia

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     

山西省鸟的种类与分布状况及对家禽禽流感的影响

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。