鱼类的洄游及影响鱼类洄游的因素和研究方法

一、洄游的类型依据洄游的主要动力,可以划分为被动洄游与主动洄游。被动洄游是指鱼类随水流而移动,在移动中本身不消耗或消耗很少的能量。主动洄游则是鱼类主要依靠自身的运动能力所进行的洄游。此外根据鱼类在洄游时所处     

鱼类行为生态学研究进展

鱼类行为学一般从鱼类的定向、信号系统、各种器官的结构和功能、高级神经作用以及复杂的行动方式等物种的特性出发,研究各种鱼类的适应性、鱼类及其特性间的生态关系以及鱼类行为各种适应性的机制.鱼类行为学不仅要研究个体鱼的行为,还要研究鱼群的行为.本文从鱼类的嗅觉、味觉、趋光性、趋音性、趋电性和洄游的行为等方面较为详细的阐述关于鱼类行为方面的知识.     

欧洲河流鱼类洄游通道恢复的研究与实践

欧洲各国虽然国情不同,但在鱼类保护问题上均面临着类似的难题,即如何恢复洄游鱼类的洄游通道;各国在该问题上密切合作与信息共享,取得了良好的效果,积累了丰富的经验。介绍了欧洲“共同体河流”项目恢复鱼类洄游通道的解决办法、监测与评价、信息交流等方面的研究与实践。     

鄱阳湖通长江水道洄游鱼类及影响因素分析

通长江水道是一些河海洄游性、江湖洄游性鱼类进行长江与鄱阳湖之间洄游的必经水域。近年来,由于围湖造田、过度捕捞、开挖湖沙、拦河筑坝等人类活动的影响,鄱阳湖的生态环境和渔业功能日渐恶化。为了解鄱阳湖洄游鱼类资源的种群变化,本文对洄游鱼类种类、群落结构及其影响因素进行了概述。     

草鱼洄游适宜流速条件与适应阈值

洄游通道的连通性及其水文条件,是制约鱼类正常洄游和产卵繁殖的关键因素,现有的生态流量相关研究更多侧重于产卵场栖息地模拟,忽略了鱼类洄游水流条件的重要性。为了探究流速条件对鱼类洄游上溯的影响,选取体长(55±5)cm的草鱼(Ctenopharyngodon idellus)为实验对象,通过搭建鱼类洄游仿真河道,营造不同的流速工况,观察不同情景方案下实验鱼群上溯洄游情况,并利用模糊逻辑法对鱼类上溯洄游率、平均上溯时间及上溯持续性等实验参数进行综合分析,探索草鱼洄游的适宜流速条件与适应阈值。结果显示,在流速0.20m/s以下时,草鱼基本无上溯行为;流速0.25～0.80m/s,70%样本在15min内完成上溯,但0.25～0.30m/s时,鱼群上溯缺乏明显的持续性;0.90～1.00m/s时,80%以上样本在5min快速完成上溯;流速超过1.1m/s时,上溯成功率明显降低。研究表明,实验草鱼洄游的适宜流速范围是0.40～1.00m/s,而刺激草鱼洄游的最小流速阈值是0.20m/s。相关结果可为河流生态水力学模拟和河流生态修复以及水利工程生态调度提供技术支撑。     

绥芬河三块鱼属（Tribolodon）鱼类的分类学讨论

绥芬河是注入日本海的水系之一 ,其溯河洄游性鱼类种类较多 ,其中被当地渔民俗称“金滩头、银滩头和黑滩头”的鱼类是鲤科唯有的溯河洄游性鱼类。在分类学上一直都存在着争议。任慕连 ( 1 981 )将其归于三块鱼Ｔｒｉｂｏｌｏｄｏｎｂｒａｎｄｔｉ (Ｄｙｂｏｗｓｋｉ)的三个不同的洄游群体 ;尹家胜 ( 1 991 )认为金滩头和黑滩头为滩头雅罗鱼ＬｅｕｃｉｓｃｕｓｂｒａｎｄｔｉＤｙｂｏｗｓｋｉ的两个不同的洄游群体 ,而银滩头为黑滩头的性不成熟群体 ;董崇智 ( 1 995,1 996 )和张觉民 ( 1 995)认为存在两个种即珠星雅罗鱼Ｌｅｕｃｉｓｃｕｓｈ…     

湘江汨罗江段鱼类资源季节变化及洄游特征研究

2017年7月-2018年6月,对湘江下游汨罗江段的仔鱼及幼鱼、成鱼开展了逐月调查,采集仔鱼1 559尾,隶属于4科12种,其中江湖洄游型鱼类7种,468尾,分别占总量的58.3%和30.0%;采集幼鱼、成鱼1 258尾,隶属于8科42种,其中江湖洄游性鱼类16种,547尾,11 486.8g,分别占总量的38.1%、43.6%和40.7%。分析结果表明,仔鱼及幼鱼、成鱼的丰度呈现明显的季节性变化特征,均为夏季高,冬季低;4-8月份,江湖洄游型鱼类的运动指数在0.1～0.7之间,呈现入湖趋势;10月份至次年3月份,江湖洄游型鱼类的运动指数在-0.7～-0.3之间,呈现出湖趋势;幼鱼、成鱼的丰度基本上夜间高于白天的;径流量和水温是鱼类出、入湖的主要驱动因子。     

高度洄游金枪鱼类资源与渔业现状

<正> 高度洄游鱼类是1982年《联合国海洋法公约》(以下简称为《公约》)第64条所指的鱼类,但《公约》没有对高度洄游鱼类下定义,一般认为,高度洄游鱼类泛指个体大、游速较快、在大洋中作长距离洄游的鱼类。《公约》附录一明确列出高度洄游鱼类有各种金枪鱼、鲔、舵鲣、鲣、枪鱼、箭鱼、旗鱼、竹刀鱼科、鲯鳅、乌鲂科、大洋性鲨鱼,甚至鲸类。与跨界鱼类资源一样,由于目前公海渔业生产中有关资源搜集困难,因此在高度洄游鱼类渔业产量统计中,只能将非公海区的产量统计也包括在其中。1970年高度洄游鱼类的渔获量为170万t,1994年约450万t,约占世界海洋捕捞总量的5％。本文仅介绍高度洄游鱼类中金枪鱼及其近缘种的资源、渔业、种群状况和管理等。     

梯级开发鱼类洄游通道恢复决策支持系统构建-以湘江干流梯级开发为例

河流梯级水电开发是我国在未来一段时间应对能源需求与结构问题的重要手段,如何缓解其对渔业资源的影响成为决策者不能回避的难题。本研究尝试将决策支持系统技术应用到这一领域,为鱼类洄游通道的恢复工作提供决策辅助。研究以湘江干流梯级开发为例,分析了梯级开发鱼类洄游通道恢复所面临的问题,构建了以空间基础数据库、决策模型库、知识库以及人机交互平台为基础的湘江干流鱼类洄游通道恢复决策支持系统。系统通过对湘江干流梯级开发的辅助决策,展现了良好的实用性。     

论恢复鱼类洄游通道规划方法

由于鱼类洄游是大尺度的水生动物迁徙运动，恢复鱼类洄游通道规划应在流域尺度进行。本文讨论了恢复鱼类洄游通道规划要点，包括河流鱼类调查及评价方法、规划范围和流域恢复洄游通道目标量化方法，提出了恢复鱼类洄游鱼类通道项目的优先排序方法，并以保护和恢复多瑙河鲟鱼规划作为典型案例进行了分析。恢复鱼类洄游鱼类通道项目的优先排序方法中，应根据工程性质、特点和当地自然条件确定优先排序准则，从而选择重点河段和重点工程，解决洄游通道中的关键问题。优先排序准则包括有效性、栖息地适宜性、效益/投资分析、自然保护区范围、预期物种多样性、鱼类生产力和栖息地面积等。在保护和恢复多瑙河鲟鱼规划案例中，确定了多瑙河鱼类洄游障碍物的5个等级划分标准和评分等级，采用改进的多准则多权重分级计分法计算了各障碍物的排序指标。在671处障碍物中，29处为最优先排序，99处为中等排序，543处为低等级排序。其中，位于多瑙河中游和下游的铁门水电站Ⅰ、Ⅱ级是流域内的主要障碍物。优先级排序方法为恢复鱼类洄游通道提供了指导意见。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.