四种重金属暴露对青鳉呼吸行为的毒性效应

研究青鳉对不同重金属污染物的敏感性和响应阈值,为水体污染特别是重金属污染的早期预警监测提供定量基础。青鳉3月龄,体长(1.5±0.1) cm,体重(0.15±0.01) g;4种重金属为Cd、Zn、Cu和Hg。研究结果表明:青鳉对Cu~(2+)、Zn~(2+)、Cd~(2+)和Hg~(2+)的急性致死毒性大小为Hg~(2+)Cu~(2+)Cd~(2+)Zn~(2+);Hg~(2+)、Cu~(2+)和Cd~(2+)暴露下青鳉呼吸频率和呼吸强度先升高再降低(P0.01),呼吸参数与重金属浓度间呈现倒"U"型关系;Zn~(2+)暴露下青鳉呼吸频率、呼吸强度显著下降(P0.01);青鳉呼吸行为对Cu~(2+)、Zn~(2+)、Cd~(2+)和Hg~(2+)4种重金属暴露的响应阈值和响应时间分别为0.15、0.95、0.15、0.045 mg/L和2 h 32 min、4 h 7.5 min、3 h 5.5 min、4 h 37 min,响应阈值与96 h LC_(50)的比值分别为0.43、0.19、0.33、0.77。青鳉对Cd~(2+)、Zn~(2+)、Cu~(2+)、Hg~(2+)污染较为敏感,其呼吸参数可作为突发性水体重金属污染的生物监测指标。     

基于IBR模型的Cu2+对厚壳贻贝的毒性效应研究

为了研究Cu~(2+)对厚壳贻贝(Mytilus coruscus)的毒性效应,开展了厚壳贻贝幼体在Cu~(2+)水溶液中的96h急性毒性效应实验及7d胁迫实验,将厚壳贻贝内脏团、鳃组织中的超氧化物歧化酶(Superoxide dismutase, SOD)、过氧化氢酶(Catalase, CAT)、脂质过氧化水平(Lipid peroxidation, LPO)以及金属硫蛋白(Metallothioneins,MT)作为生物标志物,应用综合生物标志物响应(Integrated biomarker response, IBR)指数整合4种生物标志物。结果显示,Cu~(2+)对厚壳贻贝幼体的96 h半致死浓度为1.55mg/L,内脏团、鳃组织各个生物标志物指标呈现出不同的变化趋势,内脏团、鳃组织SOD、CAT活性以及鳃组织MT含量均呈先上升后下降的趋势,内脏团组织MT含量及内脏团、鳃组织MDA含量均呈持续上升的趋势。IBR值呈先上升后下降的趋势,内脏团组织IBR值高于鳃组织。研究表明,生物标志物的变化与Cu~(2+)暴露浓度有关,IBR分析可以辨别不同暴露浓度之间的差异,可以作为量化污染物暴露效应的有效工具。     

几种重金属离子对半滑舌鳎组织损伤的研究

实验室条件下,1龄半滑舌鳎(Cynoglossus semilaevisG櫣nther)暴露在浓度为0·1×10-6mg/L的Pb~(2+)、Zn~(2+)、Cd~(2+)、Cu~(2+)溶液中。随暴露时间的延长,半滑舌鳎的行为发生一定的变化:Cd~(2+)、Cu~(2+)组的鱼行动缓慢,应激性很差,偶尔还出现不协调的颤抖性游泳行为,试验结束时几乎不摄食;Pb~(2+)和Zn~(2+)组的鱼游动积极,与实验前无大差别。利用常规组织切片法检查Pb~(2+)、Zn~(2+)、Cd~(2+)、Cu~(2+)对半滑舌鳎鳃、肝脏、肾脏、脾脏、脑的组织损伤情况。结果显示,Cd~(2+)、Cu~(2+)对鳃、肝脏和肾脏的损伤最为严重,引起了次鳃小瓣结构的崩溃;肝脏细胞脂肪颗粒的变形和大量堆积,造血组织坏死;肾小球结构溃解和管细胞肥大。Pb~(2+)、Zn~(2+)组鱼次鳃小瓣基部上皮呈空泡状,粘液细胞数量减少,氯细胞肥大增生;肝脏脂肪颗粒堆积,肝细胞肥大增生;肾脏血细胞坏死,肾小管形态溃解和管细胞增生。对脾脏和脑的损伤未观察到。将行为学变化和生理损伤结合可以对在人工养殖过程中重金属的污染及早提出预警。     

铜离子对中华绒螯蟹幼蟹的急性致死效应及组织显微结构的影响

为研究Cu~(2+)对中华绒螯蟹幼蟹的毒性机制,研究首先进行了Cu~(2+)对中华绒螯蟹幼蟹LC_(50)的测定。结果显示,Cu~(2+)对中华绒螯蟹幼蟹24,48,72和96 h的LC_(50)分别为3.824,2.779,1.941和1.666 mg/L。然后进行急性毒性试验以观察Cu~(2+)对中华绒螯蟹幼蟹肝胰腺和鳃组织显微结构的影响,试验组共4组,Cu~(2+)质量浓度分别为0,0.1,0.2和0.4 mg/L,48 h后取样并固定,制作石蜡切片观察。结果显示,低浓度组(0.1 mg/L)中Cu~(2+)也会对肝胰腺及鳃组织造成损伤,随着Cu~(2+)浓度的升高,毒性呈上升趋势,中华绒螯蟹幼蟹肝胰腺及鳃组织出现严重病理损伤。肝胰腺组织表现为细胞中出现大量空泡,基膜与肝小管单层柱状上皮分离形成空腔,甚至在肝小管中出现细胞碎片;鳃组织表现为鳃叶不规则增厚,上皮层严重损伤,甚至出现解体。研究初步探讨了Cu~(2+)对中华绒螯蟹幼蟹的毒害作用,为进一步评价Cu~(2+)在水产养殖中的危害提供了理论基础。     

Ca~(2+)对鱼类EOG的影响及其解毒作用的探讨

研究四种浓度Ca~(2+)溶液对罗非鱼嗅电图(electro-olfactogram,简称EOG)的影响,探讨Ca~(2+)对重金属中毒鱼的解毒效应,并讨论其可能机制。结果表明,①Ca~(2+)对罗非鱼EOG具双重效应;②Ca~(2+)能使重金属中毒鱼的EOG幅值增高,反映其具有一定的解毒作用,效果顺序为Hg~(2+)>Cu~(2+)>Zn~(2+)>Cd~(2+);③Ca~(2+)对Cu~(2+)+Zn~(2+)混合液也具一定解毒作用。     

重金属Cu2+、Pb2+、Cd2+对太平洋牡蛎的急性毒性效应

采用单因子急性毒性实验研究Pb~(2+)、Cu~(2+)和Cd~(2+)对太平洋牡蛎(Crassostrea gigas)的96 h半数致死浓度(96 h LC_(50))及急性毒性效应。实验结果表明,Pb~(2+)、Cu~(2+)和Cd~(2+)对太平洋牡蛎96 h LC_(50)分别为22.99、21.75 mg/L和21.35 mg/L,急性毒性作用大小的顺序为:Cd~(2+)Cu~(2+)Pb~(2+)。Pb~(2+)、Cu~(2+)和Cd~(2+)对太平洋牡蛎的安全浓度(SC)分别为:2.30、2.18 mg/L和2.14 mg/L。总体而言,与Cu~(2+)和Pb~(2+)相比,太平洋牡蛎对Cd~(2+)毒性的耐受性较低。     

重金属Cu2+对黄鳝幼鱼的急性毒性研究

为研究黄鳝幼鱼对水体中Cu~(2+)的耐受性,在水体硬度(以CaCO_3计) 60 mg/L、p H为7.2、水温(26.2±1.2)℃的条件下,对体质量(12.52±0.12) g的黄鳝幼鱼进行了Cu~(2+)急性毒性试验。结果表明,Cu~(2+)对黄鳝幼鱼24、48、72、96 h的半致死质量浓度(LC_(50))分别为6.764、4.971、1.930、1.029 mg/L,安全浓度(SC)为0.109 2 mg/L; Cu~(2+)对黄鳝幼鱼的毒性为高毒等级。黄鳝幼鱼急性中毒症状表现为:离开水底做无规律游动,体表分泌大量黏液,肛门红肿,身体绷直,将吻端探出水面,鳃腔内可见血块。建议在黄鳝养殖过程中应尽量减少铜制剂的使用。     

Cu~(2+)对鲫鱼过氧化物同工酶表达的影响

研究不同浓度的Cu~(2+)对鲫鱼过氧化物同工酶表达的影响。用四个不同浓度梯度的硫酸铜溶液饲养鲫鱼,处理4d后,使用聚丙烯凝胶垂直平板电泳法,研究不同浓度的Cu~(2+)对鲫鱼肝脏、鳃过氧化物同工酶的影响。结果显示,不同浓度的Cu~(2+)都有可能使肝脏、鳃组织过氧化物同工酶带强弱发生较明显的变化,并且对其组织过氧化物同工酶的影响显现出一定的组织差异性,在一定量的浓度范围内表现出应激性,可以说,低剂量的铜离子可以诱导酶活性的提高。     

硫酸铜对水产动物的毒性研究现状

重金属Cu~(2+)既是水产动物所必须的矿物元素之一,也是水体常见的污染源。水体中高浓度Cu~(2+)会对水产养殖动物造成急性中毒从而致死,而亚致死剂量Cu~(2+)也可造成水产动物慢性中毒,对其组织器官、神经系统、免疫系统等造成不可逆的损伤。本文对水产养殖中常见杀虫剂硫酸铜对水产动物慢性毒性、急性毒性、安全浓度等的研究现状进行了综述。     

4种重金属离子对菲律宾蛤仔的急性毒性及安全评价

为探究菲律宾蛤仔对Cd~(2+)、Mn~(2+)、Zn~(2+)、Cu~(2+)的耐受能力,采用毒理学试验方法研究4种重金属离子对菲律宾蛤仔的急性毒性效应。试验结果显示,菲律宾蛤仔的死亡率与4种重金属离子的质量浓度成正比,表现出明显的剂量—效应关系。4种重金属离子对试验菲律宾蛤仔24、48、72、96 h的半数致死质量浓度分别为:Cd~(2+),38.62、29.83、8.11、2.67 mg/L;Mn~(2+),712.58、421.57、188.74、61.27 mg/L;Zn~(2+),141.27、72.20、34.91、21.57 mg/L;Cu~(2+),29.88、12.06、3.62、0.79 mg/L;Cd~(2+)、Mn~(2+)、Zn~(2+)、Cu~(2+)对菲律宾蛤仔的安全质量浓度分别为0.03、0.61、0.22、0.01 mg/L。试验结果表明,4种重金属离子对菲律宾蛤仔毒性强弱依次为Cu~(2+)Cd~(2+)Zn~(2+)Mn~(2+),Cu~(2+)对菲律宾蛤仔的安全质量浓度低于渔业水质标准,在育苗和养殖过程中需特别关注。     

Hemoglobin level,metabolic rate,opercular abduction rate and swimming efficiency in female triploid brook trout (Salvelinus fontinalis)

Metabolic (oxygen consumption) rate, opercular abduction rate and tail beat frequency were determined in two strains of diploid and triploid female brook trout (Salvelinus fontinalis) while these fish swam at 0.37±0.02 body lengths per sec in a Blazka respirometer. Total blood hemoglobin level was also measured and opercular condition examined. Total blood hemoglobin levels in diploids and triploids were equal. The opercular abduction rate was the same in diploids and triploids (regardless of whether triploid opercular condition was good or poor) yet triploids had a lower oxygen consumption rate than diploids, indicating that triploids take up less oxygen than diploids per opercular cycle. Tail beat frequency, an indicator of swimming effort, was the same in diploids and triploids, suggesting that triploids require less oxygen than diploids for a similar swimming effort.     

电麻醉对西伯利亚鲟幼鱼行为特性与血清离子浓度的影响

研究了不同强度电麻醉对西伯利亚鲟幼鱼行为特性与血清离子浓度的影响。西伯利亚鲟电麻醉阶段包括部分失去平衡期、完全失去平衡期、完全麻醉期和鳃动停止期等4个时期。电麻醉时西伯利亚鲟呈现趋阳性;随着电压升高,到达各麻醉阶段时间与恢复时间逐渐缩短。西伯利亚鲟到达完全麻醉期时间在15 V、20 V、25 V、35 V组间均有显著差异,在30 V与35 V时分别仅为97.0 s和68.8 s,而恢复时间为0 s。各试验组西伯利亚鲟在电麻醉时鳃动频率均增加,而恢复阶段均降低。电麻醉对西伯利亚鲟摄食与活动状态均无显著影响。随着电压升高,钾离子与镁离子浓度先下降后上升,钙离子则先上升后下降。钠离子与氯离子浓度变化较大,均是15 V组时浓度最低,20 V时浓度最高。磷离子浓度呈现增高趋势。pH值在麻醉后降低,对照组与其余各组均有显著性差异。因此西伯利亚鲟幼鱼适宜电麻醉强度为25~30 V,电麻醉是种较好的麻醉方法,具有广泛的应用前景。     

DECREASED TOXICITY OF COPPER AND MANGANESE IONS TO SHRIMP NAUPLII (Penaeus stylirostris STIMPSON) IN THE PRESENCE OF EDTA

Although ethylenediaminetetraacetic acid (EDTA) is used routinely in the intensive culture of penaeid shrimp larvae to increase both the percentage of eggs that hatch and the survival of larvae, the mode of action is not known. To explain EDTA's beneficial effect this study compares the toxicities of copper and manganese divalent ions in the presence and absence of 10 mg EDTA/liter seawater. Toxicity was evaluated in terms of the percentage of Penaeus stylirostris nauplii surviving after 12 and 24 hours of exposure to either copper or manganese and in terms of the percentage of nauplii that metamorphose to the protozoeal stage. In the absence of EDTA, copper and manganese ions were toxic to nauplii with copper causing 100% mortality at a much lower concentration (20 μM) than manganese (20,000 μM). In the presence of EDTA, survival of nauplii exposed to copper was increased but survival of nauplii exposed to manganese was not affected. At concentrations lower than the levels that reduce survival, copper ions (0.2 μM) and manganese ions (2 μM) reduce the percentage of nauplii that metamorphose to protozoea. In the presence of EDTA, the percentage of nauplii that metamorphose to protozoea is increased with both nauplii exposed to copper ions and nauplii exposed to manganese ions. The beneficial effects of EDTA are probably due to the chelation of copper and manganese ions by EDTA. Chelation lowers the free concentration of these ions and thus reduces their toxicities.     

Patterns and predictors of fish dispersal in rivers

Quantifying fish dispersal and identifying its general predictors is key for understanding temporal patterns in population dynamics, emigration and immigration, meta‐community dynamics, many ecological processes and predicting recovery time or population responses to environmental changes. This is the first comprehensive quantitative meta‐analysis of heterogeneous freshwater fish movement, aiming to determine mobile and stationary shares of fish communities, their dispersal distances and key predictors of dispersal patterns. By reviewing and analysing 160 empirical data sets from 71 studies covering 62 fishes in streams, it goes beyond previous studies of salmonids’ heterogeneous movement. Based on fitted leptokurtic dispersal kernels, the movement distances of (i) a stationary component (σ_stat) and (ii) a mobile component (σ_mob) as well as the (iii) share of each component (p) were calculated. The median movement distance of the stationary and mobile component of a fish population was 36.4 and 361.7 m, respectively. The share of the stationary individuals was high (median = 66.6%), but unrelated to movement distance. Single and multiple linear regressions as well as mixed‐effects models revealed movement distances positively related to fish length, aspect ratio of the caudal fin, stream size and duration of the study. Furthermore, movement distance differed between taxonomic families. The quantitative parameters of heterogeneous fish movement provided are prerequisite to estimate time lags in fish response to river rehabilitation, temporal patterns in species dispersal, and minimum effective size of potential founder populations for species conservation and stock recovery based on minimum numbers of specimen to disperse.     

A modeling approach to evaluate growth and movement for recruitment success of Japanese sardine (Sardinops melanostictus) in the western Pacific

A two‐dimensional individual‐based fish movement model coupled with fish bioenergetics was developed to simulate the observed migration and growth of Japanese sardine (Sardinops melanostictus) in the western North Pacific. In the model, derived from the observed ocean–environmental data as the driving force, fish movement was adapted as a kinesis behavior. The model successfully simulated the observed transport patterns during the egg and larval stages and the northward migrations during the juvenile stage in 2005, 2006 and 2007. The model results showed that both temperature during the larval stage in the Kuroshio Extension and the prey availability during the early juvenile stage in the Kuroshio–Oyashio transitional area are important factors for growth of Japanese sardine. In autumn, the observed juvenile sardine were mainly distributed in the subarctic water region off the Kuril Islands, which is an area (158–165°E, 43–47°N) with a high chlorophyll‐a (Chl‐a) concentration. The model reproduced the fish distribution, which has a high density in this region. The high Chl‐a concentration area in autumn may contribute to increasing the survival rate of Japanese sardine by cascading up the food chain, from the high primary production, and is an important habitat for recruitment success of Japanese sardine.     

Testing the ability of habitat selection theory to predict interannual movement patterns of a drift-feeding salmonid

Abstract – This article extends the logic of a habitat selection model (Hughes, Ecology , 1998) to make predictions about the way body size will influence the probability that fish will make a long distance interannual movement, from the feeding position it occupies in one summer to the position it occupies the next. The model predicts that the probability of this kind of movement will fall as fish grow and reach zero for the largest fish in the population. I tested these predictions using data on Arctic grayling Thymallus arcticus in the lower 140 km of a 260-km-long interior Alaskan river. Both predictions of the model were well supported by the data. As expected, the probability a fish will make a long-distance interannual movement decreased with fish size, and the largest fish in the population had a movement probability of zero. ^NOTE     

Using knowledge of behaviour and optic physiology to improve fish passage through culverts

Culverts reduce connectivity for aquatic animals by being both a hydraulic and physical barrier. However, altered light intensity may also be a behavioural barrier to fish movement, especially for diurnal species that have adapted to moving when it is light. We propose that knowledge of optical physiology and fish behaviour, two important mechanisms underpinning movement, can inform efforts to improve fish movement through culverts. We firstly review the sensory systems of fish with reference to visual sense and explore how this affects fish movement. We then highlight theoretical knowledge that can help us understand fish behaviour and the potential mismatch between the conditions under which fish have evolved and altered conditions within culverts. We describe potential knowledge gaps and directions for future research to improve our understanding of how culverts may affect fish movement. Finally, we explore the potential costs and ecological benefits of different mitigation options to identify those with the most promise for managing the light environment in culverts to facilitate movement. For researchers and managers exploring this subject, we suggest an approach that: (a) identifies light requirements for movement by different species, (b) tests movement under different light conditions and (c) considers an integrative assessment method for testing fish behaviour around culverts. Understanding how optical physiology, fish behaviour and culvert design influence fish movement can improve connectivity for a range of species.     

Numerical modeling of chaotic behavior for small-scale movements of demersal fishes in coastal water

ABSTRACT:   The presented model involves the application of chaos theory to generate fish movements resulting from environmental stimuli. The model uses three steps within a model neural network such as input stimuli, central decision making and response output resulting in fish movements. The stimuli in the first step include the main abiotic and biotic factors, which could be quantified as an intensity parameter that was then normalized as a ratio between 0 and 1. The decision-making process can be generated using chaos dynamics with the stimuli parameters. The response of fish movements from the output signal representing movement speed and direction of fish can be re-regulated as main movement pattern depending on physiological state or life cycle by third response filtering. The simulation results seen as a movement pattern for sea bream and flounder using this neural chaotic model fitted very well to the observations of fish tracked in the sea by ultrasonic tracking methods. It was also revealed that the fish movement components generated as movement velocity and direction when in tidal flow had similar patterns to those patterns seen in field observations with similar irregular and chaotic variations with time.     

Some impacts of low and medium head weirs on downstream fish movement in the Murray–Darling Basin in southeastern Australia

Abstract –  This article reports on the findings of a study undertaken within the Murray-Darling River Basin in southeastern Australia, which investigated the impact of weirs on downstream fish movement. Downstream fish movement was monitored at Kennedy's Weir (an overshot, 2 m high weir) on the Broken Creek and Torrumbarry Weir (an undershot, 6.5 m high weir) on the Murray River. A trap used to sample Kennedy's Weir indicated that fish travelled downstream over this weir without sustaining injury or death. A follow-up study, whereby fish were captured below the two respective weirs and translocated upstream where they were radio tagged and released, indicated that while a few fish travelled downstream past the weirs on their return movements back to their home range areas, most were reluctant to do so. This study demonstrates that low-level weirs may inhibit downstream fish movement, and enhancement of downstream fish passage for potamodromous fish species warrants further investigation.     

Recovery of opercular anomalies in gilthead sea bream, Sparus aurata L.: morphological and morphometric analysis

Opercular anomalies are very frequent in reared gilthead sea bream and these can negatively influence the product value. Field observations have suggested that opercular malformations can recover over time. In order to verify this hypothesis, 140-day-old gilthead sea bream with monolateral opercular anomalies were divided into three groups, according to the type and increasing seriousness of the opercular malformations, and another group was composed of fish with bilateral opercular anomalies. All groups were monitored for 16 months. In the group with monolateral anomalies, the opercular recovery process was documented by morphological (stereomicroscope) and morphometric analysis. For the latter analysis, two relevant areas, A and T, were identified in the cephalic region. The ratio (T - A)/T, tending to 1, represents the recovery index (RI) of anatomical integrity and quantifies the recovery level of opercular complex anomalies. Results suggested that the recovery process was considerable over the 16 months of investigation but should not be considered complete. At the end of the study, 61% of the gilthead sea bream population with monolateral opercular defects recovered external integrity, whereas the population with bilateral defects showed a poorer recovery capability.