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滚筒去鳞是鱼类连续去鳞加工的有效方法之一,虽然国内已有去鳞设备应用于实际生产,但实际去鳞效果和损伤等方面还无法完全满足生产需求。为探究不同去鳞部件在滚筒式去鳞加工过程中的实际效果和影响因素,该研究选取钢板网、圆形孔网、角钢刀具和螺纹钢4种去鳞结构件,设计滚筒去鳞实验装置并开展工艺参数研究,测量不同条件下去鳞率并观察分析损伤情况,在此基础上设计多段滚筒去鳞装置并进行试验验证。结果显示,去鳞时间和滚筒转速是影响钢板网和圆形孔网去鳞效果的主要参数,不同去鳞时间下的去鳞率差异显著,去鳞率随时间延长不断上升。在滚筒转速为35 r/min,去鳞时间接近4 min时,去鳞率可达95%;相同时间和转速下,各去鳞部件的去鳞效果依次为钢板网角钢道具圆形孔网螺纹钢,对鱼体的损伤程度依次为螺纹钢圆形孔网角钢道具钢板网;钢板网和圆形孔网组合式多段滚筒去鳞装置,在转速为35 r/min,去鳞时间为3 min时的最高去鳞率可达95%,且损伤率低。研究获得的适宜罗非鱼多段滚筒去鳞装置的工艺参数,可为罗非鱼滚筒去鳞设备的完善和优化提供依据。 相似文献
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鲢鱼是淡水渔业的主要养殖品种 ,随着人们生活水平日益提高 ,小规格鲢鱼销路不佳 ,加工是鲢鱼养殖业持续发展的重要途径。目前以鲢鱼为原料的加工品种主要有鱼糜、冷冻鱼糜及其制品 ;调味鱼块软、硬罐头 ;盐腌制品等几类 ,但原料鱼头、尾、皮、鳍、脊骨等下脚料的综合利用一直不甚理想。1 998年以来 ,我们在以小规格鲢鱼为原料研制珍味鱼干、熏鱼脯时 ,将下脚料采用臭氧化技术去除淡水鱼土腥味 ,小批量加工鱼鲜酱、鱼鲜辣酱、鱼鲜麻辣酱、八宝鱼鲜酱等系列鱼酱 ,受到消费者好评。该工艺除生产鱼酱类产品外 ,还可以加工成方便面的鱼鲜酱料包… 相似文献
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为了保护和开发鸭绿江淡水鱼资源,维护中朝两国人民利益、宽甸县于10月10日开始向鸭绿江投放鲢鱼、草鱼、鳙鱼等鱼苗100万尾。这批鱼苗长度都在10厘米以上,生殖力较强,是由县鱼种场培育养殖的。第一批投放的10000余尾小鱼已在鸭绿江中畅游,到本月末将全部投放完毕。这对于鸭绿江淡水鱼的繁殖、沿江两国人民的捕捞创造了良好条件。 相似文献
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G. Fontenelle G. Douaire P. Prouzet Y. Harache J. L. Baglinière 《Aquaculture Research》1980,11(3):87-100
This paper presents some characteristics (length, weight and age) of adult Atlantic salmon in rivers of Brittany. The data were derived from 1,578 fish caught mainly by rod and line; the remainder being from net catches in estuaries and small samples taken outside the fishing season. The bulk of the fish spent 1 or 2 years in freshwater before smoltifying. Those fish becoming smolts at the end of 1 year were the most numerous (54%). The majority of the fish sampled were spring fish (82.4%). Very few summer fish were identified and those found were mainly grilse. The high proportion of spring fish in the sample is due to the high proportion of rod-caught fish. Probably a complete census over the year would show a larger proportion of grilse and summer fish as these are not subject to heavy rod-fishing the season being closed at the beginning of June. The relationship between sea age and river age and the influence of freshwater life upon the sea life were tested in four rivers. It seems probable that sea life depends chiefly on the river and the year of smoltification rather than on the freshwater stage. The biometric characteristics of Brittany salmon were compared with data from some foreign rivers. The angling exploitation of the spring Atlantic salmon in Brittany and the lack of data about summer migrations are discussed in regard to the future of this stock. 相似文献
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Abstract – Fishery biologists have documented small home ranges, relative to available habitat, for many littoral freshwater fishes. Home ranges for pelagic species, such as white bass Morone chrysops , are generally not well described, yet are thought to be large. We studied white bass movement using acoustic telemetry in two irrigation reservoirs of the Republican River basin in south-western Nebraska. Acoustic transmitters were implanted in fall of the previous year and tracking occurred a minimum of once per week throughout spring (mid-March to May) 2007 and 2008. Linear home ranges were calculated from observed locations of individual fish. Twelve of the twenty-seven tagged fish with at least five locations exhibited localised home ranges throughout the spring whereas the remaining fish exhibited home ranges extending across large portions of each reservoir. Home range size was not correlated with fish size or condition. 相似文献
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R. A. Cunjak 《Ecology of Freshwater Fish》1992,1(1):26-34
Abstract– The diet composition, movcments and growth of Atlantic salmon parr rearing in the estuary of Western Arm Brook, Newfoundland were compared with those of parr from riverine habitats over 2 years. Estuarine parr consumed a variety of prey, including many freshwater taxa (mainly insects), which indicated a dependence on freshwater drift from the river. Prey of estuarine origin (amphipods and sticklebacks) were increasingly consumed between spring and autumn. Prey volume per fish and number of prey per fish increased significantly for estuarine parr between spring and autumn, suggesting an improvement in food availability. Riverine parr, however, realized a general decrease in both parameters between spring and autumn. The recapture of 16% ( n = 131) of the 829 parr marked in the estuary in 1987 and 1988 indicated a directed movement toward the head of the estuary and river mouth, as also suggested by the diet analysis. Parr from outer estuary sites were very mobile compared with parr from the estuary site closest to the river mouth, which behaved more like parr in the river proper in displaying strong site fidelity. Movement patterns of parr were primarily along the shoreline. Individual growth rates were highly variable in both environments but especially in the estuary. The mean growth of estuarine parr was 0.23 mm. d−1 between May and October with some evidence of fastest growth having occurred in late spring and early summer (approx. 0.4 mm. d−1 ); mean growth rate of riverine parr was slower, at 0.12 mm. d−1 . The results are discussed in the context that estuarine rearing by salmon parr represents an alternative life-history tactic for the species in river systems in eastern Canada. 相似文献
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带鱼保护区春秋季鱼类群落特征及与环境因子的关系 总被引：2，自引：0，他引：2
基于2014年5月(春季)和11月(秋季)在带鱼保护区进行的渔业资源底拖网调查数据,采用非度量多维标度(NMDS)、典范对应分析(CCA)和分类回归树(CART)方法研究了带鱼保护区春、秋季鱼类群落空间结构和群落多样性,以及它们与环境因子的关系。结果显示,该水域春季共捕获鱼类75种,隶属14目49科63属;秋季捕获鱼类78种,隶属15目50科64属。春、秋两季鱼类空间结构均可划分为2个组群,经单因子相似性(ANOSIM)分析,不同季节的2个组群间均存在显著性差异。CCA分析表明,影响春、秋季鱼类群落分布的主要环境因子有温度、盐度、水深以及浮游动物。春季多样性指数平均值为1.65±0.60,丰富度指数为2.46±0.90,秋季多样性指数平均值为1.42±0.53,丰富度指数为1.89±0.60。CART分析表明,影响春季多样性和丰富度的主要因素有Chl.a、DO、水深、p H和浮游动物(磷虾类和浮游幼体);秋季多样性主要受温度、水深和盐度的影响,丰富度主要受水深和温度的影响。 相似文献
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为探究福建中部近海鱼类生态类群组成的季节变化,采用非线性多维标度(NMDS)和相似性检验(ANOSIM)方法,依据2009年冬季、2010年春季和夏季于福建中部近海3个航次的海洋综合调查资料,对该海域鱼类的种类组成和生态类群结构进行分析。结果显示,冬季出现鱼类40种,生态类群以暖水种为主,但暖温种比例为3个季节中最高(30%),且暖温种占该季鱼类总质量和总尾数比例分别为17.65%和16.96%。春季出现鱼类39种,生态类群以暖水种为主,分别占该季节鱼类总质量和总尾数的86.48%和94.52%。夏季出现鱼类61种,暖水种占绝对优势(56种),分别占该季鱼类总质量和总尾数的97.17%和99.35%。受浙闽沿岸流和台湾海峡暖流的交替影响,从冬季到夏季物种更替率逐渐升高,暖水种种类数和数量密度不断上升,并伴随着河口种消失、外海种出现。此现象与冷、暖水团交替影响这一海域时,鱼类进行相应的产卵、索饵及越冬洄游等有关。研究表明,福建中部近海鱼类生态类群和种类组成的季节变化可能由水团不断变化所导致。 相似文献
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Abstract Fixed location hydroacoustic fish monitoring was carried out at a series of sites in the tidal River Hull, north-east England, in July 1996 during periods of moderate freshwater flows and spring tides. This was followed by a corresponding series during a period of lower freshwater flows and spring tides in autumn 1996. The surveys indicated substantial numbers of fish living upstream and downstream of a depleted oxygen zone which exists in the tidal Hull. Conditions in this zone of poor water quality deteriorated further during low flow periods due to reduced dilution of effluents. Fish populations moved with the tide apparently in response to gradients of dissolved oxygen and salinity. Under conditions of low freshwater flow and high tides, gradients of salinity and oxygen were steeper and fish responses appeared more marked: at higher salinities, the response to increasing salinity overrode the response to decreasing oxygen availability. 相似文献
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The Negombo estuary brush park fishery in Sri Lanka was investigated from June 1998 to March 1999. The mean fish yield (all species) in the fishery was 12.46 t ha−1 yr−1 . Fin fish species formed about 91% of the yield and the rest was formed by penaeid shrimps and crabs. Fish yield and the twig density in the brush park exhibited a second order polynomial relationship indicating a minimum yield at an intermediate value of twig density in the brush parks. The relationship between fish yield and duration of implantation of brush parks showed an optimal period of 30–40 days for high fish yields. Income levels of fishermen, availability of construction material and suitable sites for implantation of brush parks are some of the factors determining size and number of brush parks per fisherman and duration of installation. Indigenous knowledge within the fishing community about the effect of salinity variations, twig density and mangrove species used on the harvests greatly contribute to effective operation of this fishing practice. Cultivation of mangroves to obtain twigs and branches is a unique feature in this estuary. Indigenous knowledge on mangroves has led to the adoption of sound silvicultural practices. Although cultivating mono-specific mangrove stands may not increase diversity of mangrove forests, it reduces denudation of naturally occurring mangrove forests because of brush park construction, and retains habitats for other organisms. Mangrove management plans in the Negombo estuary should therefore be viewed and treated in an integrated manner that takes into account both resource and social components. 相似文献
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Chuanbo Guo Yushun Chen Rodolphe E. Gozlan Zhongjie Li Thomas Mehner Sovan Lek Craig P. Paukert 《Fish and Fisheries》2019,20(5):857-869
Understanding drivers of freshwater fish assemblages is critically important for biodiversity conservation strategies, especially in rapidly developing countries, which often have environmental protections lagging behind economic development. The influences of natural and human factors in structuring fish assemblages and their relative contributions are likely to change given the increasing magnitude of human activities. To discriminate natural and human drivers of fish diversity and assemblage patterns in developing countries with rapid socio‐economic development, a dataset of 908 freshwater fish species and 13 metrics including three categories of both natural (i.e., biogeographic) and human drivers (i.e., economic growth, inland fisheries) in China were analysed with machine learning algorithms (i.e., self‐organizing map, random forest). Here, we found that biogeographic drivers explained 21.8% of the observed fish assemblage patterns in China and remained stronger predictors when compared to human drivers (i.e., 15.6%, respectively). Freshwater fish species richness was positively correlated to rainfall, air temperature, surface water area and inland fisheries production but negatively correlated with urbanization. In addition, the strong structuring effects of climatic variables on Chinese fish richness patterns suggested that the fish assemblages could be particularly vulnerable to climate change. Our results showed that natural biogeographic factors still dominate in driving freshwater fish assemblage patterns despite increased human disturbances on aquatic ecosystems in a rapidly developing country. These findings consequently suggested that we should consider both natural (e.g., climate) and human (e.g., urbanization, inland fisheries) factors when establishing aquatic conservation strategies and priorities for developing countries that are experiencing rapid socio‐economic changes. 相似文献
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Ulla Nordgarden Tom Hansen Gro-Ingunn Hemre Anne Sundby Bjrn Thrandur Bjrnsson 《Aquaculture (Amsterdam, Netherlands)》2005,250(3-4):862-871
Plasma growth hormone (GH), insulin-like growth factor-I (IGF-I), and insulin were measured in two groups of Salmo salar L. during a one-year study. The fish were reared under either a simulated natural photoperiod (SNP) from January to December or a regime of continuous light from January to June, followed by SNP until December (LL/SNP). Plasma GH levels during spring were low, and lower in the LL/SNP fish (< 0.9 ng ml− 1) than in the SNP fish (> 1.9 ng ml− 1), although the LL/SNP grew better (0.8% per day) than the SNP fish (0.5% per day). Plasma IGF-I levels increased transiently from January (64.7 ng ml− 1) to maximum in late September in the LL/SNP (85.8 ng ml− 1) and in November in the SNP group (87.3 ng ml− 1). The ratio GH:IGF-I was lower in the LL/SNP group during spring when this group grew better than the SNP group. 相似文献