象山港大型底栖动物生态学初步研究

2006年7月至2008年8月对象山港水域大型底栖动物进行了四季采样分析,采样站位包括13个大面站位和10个电厂站位。共鉴定出大型底栖动物123种,其中软体动物48种,甲壳类33种,鱼类和环节动物多毛类各12种。2个调查周年,本区大面站位年均栖息密度分别为145.54个/m2和109.36个/m2,年均生物量分别为28.22g/m2和30.02g/m2。在电厂站位中,国华电厂年均栖息密度分别为49.58个/m2和46.65个/m2,年均生物量分别为14.49g/m2、15.99g/m2。乌沙山电厂年均栖息密度分别为45.83个/m2、45.21个/m2,年均生物量分别为14.60g/m2、13.81g/m2。研究表明,象山港大型底栖动物分布不均匀,支港流域年均密度、生物量明显高于主港流域;电厂区域的大型底栖动物密度和生物量均低于全港的平均值。在季节周期变化上,电厂站位的变化差异低于大面站位。     

旅顺南部基岩海岸潮间带大型底栖动物的群落结构研究

于2010年6月对大连市旅顺口区南部基岩海岸潮间带大型底栖动物的种类、生物量、栖息密度进行了调查,对生物多样性和次级生产力进行了计算.调查结果表明,调查区域大型底栖动物20种,其中腔肠动物1种,环节动物1种,软体动物13种,节肢动物5种.大型底栖动物的平均生物量为4312.5 g/m2,平均栖息密度为2966个/m2....     

洋山深水港海域大型底栖动物初步研究

2003~2005年每年2月、5月和8月按《海洋监测规范》中大型底栖动物调查方法,分别对洋山深水港一期工程施工海域(30°30′~30°54′N、121°45′~122°30′E)20个取样点进行了大型底栖动物调查。根据调查结果,分析与讨论该海域底栖动物的种类组成、生物量、栖息密度和群落多样性的分布与变化。监测结果显示:一期工程施工期,底栖动物的种类数逐年减少,2003~2005年种类数分别为21种、17种和16种;底栖动物栖息密度逐年下降,2003年(31.10 ind/m2)>2004年(12.50 ind/m2)>2005年(11.00 ind/m2);底栖动物平均总生物量总体表现为逐年降低,2003年(4.26 g/m2)>2005年(2.18 g/m2)>2004年(0.62 g/m2),2004年生物量下降尤为显著,2005年生物量略有回升;生物多样性指数也逐年降低,2003~2005年分别为0.81、0.36和0.16。三年监测结果表明,洋山深水港一期工程海域施工期底栖动物种类数、总生物量、栖息密度以及多样性指数总体呈逐年下降趋势,群落结构趋于简单化,说明工程海域施工期对大型底栖动物产生了一定程度的影响。     

澜沧江大型底栖动物群落结构及分布格局

2009年4月-2011年8月,对澜沧江流域的大型底栖动物群落结构、现存量和分布格局进行了4次调查,涉及澜沧江云南段和西藏段的34个采样点。结果显示,大型底栖动物共119种(属),隶属于4门7纲66科,平均密度为243.2 ind./m2,平均生物量为13 016.8 mg/m2,水生昆虫为该流域优势类群。澜沧江流域大型底栖动物的密度、生物量纵向分布呈现高-低-高的分布规律,下游的多样性高于中、上游,科级聚类显示生境相似样点大型底栖动物群落结构类似。与地理环境类似的怒江相比,澜沧江的大型底栖动物密度、生物量组成差异不大,但种类数显著高于怒江。     

北京密云水库大型底栖动物群落结构及水质生物学评价

为探究北京密云水库大型底栖动物群落结构及其与环境因子和水质的关系,根据水库形状和水位季节变化规律,在潮河库区(1~3号)、库中区(4~5号)以及白河库区(6~8号)共设置8个采样点,于2015年4月(春季)、8月(夏季)、10月(秋季)下旬进行采样,冬季由于水库结冰采样困难而未采集底栖动物样本。结果显示,密云水库共检出大型底栖动物15种,隶属2门2纲2科10属,其中环节动物门颤蚓科4种,节肢动物门摇蚊科幼虫11种,优势种为正颤蚓(Tubifex tubifex)和红裸须摇蚊(Propsilocerus akamusi)。不同采样点的种类数为2~11种,年均密度和年均生物量分别为1864个/m2和3.10g/m2,显示密云水库为中营养型水库。底栖动物年均密度:白河库区潮河库区库中区,年均生物量:白河库区潮河库区及库中区。在库西、白河电站等深水区,颤蚓类密度和生物量占比较高;而浅水区摇蚊幼虫密度和生物量占比较高。底栖动物总密度:夏季春季秋季;总生物量:春季夏季≈秋季。水库中颤蚓类的密度和生物量与水深、沉积物中总有机碳及总氮含量呈显著线性或幂函数正相关,与沉积物中总磷含量相关不显著;摇蚊幼虫的密度和生物量与上述4个环境变量均无显著相关性。底栖动物Shannon-Wiener多样性指数、Margalef丰富度指数、Goodnight修正指数和Pielou均匀度指数在浅水区高于深水区。Pielou均匀度指数和Wright指数评价表明,密云水库水质为轻污染,与水化评价结果比较一致,可作为水质生物学评价的重要参考。     

怒江西藏段大型底栖动物群落结构及多样性研究

于2007年、2008年的7月先后2次对怒江流域西藏段干、支流大型底栖动物进行了调查。应用ShannonWiener、Margalef和Pielou指数分析了干、支流大型底栖动物的多样性,结果显示:17个采样断面(干流8个,支流9个)共采集到底栖动物34种(属),隶属于25科,其中以水生昆虫种类最多(76.0%);研究区域内干、支流底栖动物密度和生物量分别为132.77 ind/m2、3 967.51 mg/m2,95.39 ind/m2、2 339.64 mg/m2;干流底栖动物现存量明显高于支流,但其物种多样性(H、D、J)组成却低于支流。研究发现,干、支流大型底栖动物群落结构的差异主要与底质类型有关,底栖动物生物多样性与海拔高程变化之间无明显关系。     

浙江六横岛泥滩潮间带大型底栖动物的群落特征

本文分析了浙江六横岛泥滩潮间带大型底栖动物的种类组成、数量分布和多样性指数等群落特征。3个泥滩潮间带断面调查采获的大型底栖动物共有19种,其中软体动物10种,节肢动物6种,脊索动物2种,环节动物1种。3个泥滩潮间带断面总平均生物量为470.77±314.32 g/m2, 总平均栖息密度为480±248 ind./m2。在各类群底栖动物中,平均生物量及密度都以软体动物居首位。六横岛潮间带大型底栖动物的Shannon-Wiener多样性指数、Margalef丰富度指数和Pielou均匀度指数的分布范围分别在1.97-2.14、1.45-1.67和0.83-0.95,平均值分别为2.06±0.08、1.53±0.12和0.90±0.06。六横潮间带大型底栖动物ABC曲线分析表明底栖动物群落已受到一定程度的污染扰动。     

怒江流域大型底栖动物资源状况

2007年4月到2008年8月对怒江流域大型底栖动物种类组成、分布和生物量先后进行了5次调查,共获得大型底栖动物53种,隶属于5门,7纲,42科,其中水生昆虫是怒江流域鱼类饵料的重要来源之一.怒江流域42个采样点大型底栖动物密度、生物量分布从上游到下游呈高—低—高的变化规律,其密度和生物量值的变化范围分别为5.55～4...     

拉萨河中下游底栖动物群落结构特征分析

2013年10月,在拉萨河热震藏布-河口中下游河段及支流共设置16个采样断面(拉萨河干流10个、支流4个,雅鲁藏布江汇口2个),对底栖动物进行了调查。样品分析结果表明:拉萨河评价河段干、支流底栖动物共31种,其中环节动物5种,占16.13%;软体动物3种,占9.68%;节肢动物23种,占74.19%。优势种有正颤蚓(Lumbricus tubifex)、四节蜉(Baetidae sp)、多足摇蚊(Polypedilum sp)、隐摇蚊(Cryptochironomus sp)、网石蝇(Perlodidae sp)、钩虾(Gammaridae sp)等。直孔电站影响河段底栖动物现存量较高,密度、生物量平均分别为31 911个/m2、117.65 g/m2。剔除直孔电站影响河段,拉萨河干流底栖动物密度、生物量分别为32个/m2、0.92 g/m2,支流密度、生物量分别为63个/m2、0.78 g/m2。底栖动物Shannon-Wiener指数为0~2.02。直孔电站运行对拉萨河中、下游河段底栖动物整体影响较小;对库区河段底栖动物群落结构影响较大,群落结构由流水型向耐氧、静水型的环节动物、摇蚊转化。     

浙江六横岛潮间带大型底栖动物的群落特征研究

分析了浙江六横岛潮间带大型底栖动物的种类组成、数量分布和多样性指数等群落特征.3个断面采获的大型底栖动物共有19种,其中软体动物10种,节肢动物6种,脊索动物2种,环节动物1种;总平均生物量为(470.77±314.32)g/m2, 总平均密度为(480±248)个/m2.在各类底栖动物中,平均生物量及密度都以软体动物居首位.大型底栖动物的Shannon-Wiener多样性指数、Margalef丰富度指数和Pielou均匀度指数分别为1.97～2.14、1.45～1.67和0.83～0.95,平均值分别为(2.06±0.08)、(1.53±0.12)和(0.90±0.06).ABC曲线分析表明,底栖动物群落已受到一定程度的污染扰动.     

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.