渔山列岛潮间带大型底栖动物的群落结构

于2009年3月的大潮期间对渔山列岛潮间带布设5个断面,进行大型底栖动物调查。结果表明,该海域潮间带采集到大型底栖动物90种,其中腔肠动物3种,多毛类11种,软体动物45种,甲壳类19种,棘皮动物6种,其它6种。潮间带大型底栖动物总平均生物量5307.06g/m2,总平均丰度为2323.20ind/m2。在各类群底栖动...     

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.     

浙江6个列岛潮间带大型底栖动物分类多样性

为揭示浙江6个重要列岛(嵊泗列岛、中街山列岛、渔山列岛、台州列岛、洞头列岛、南麂列岛)潮间带大型底栖动物分类多样性和更好地养护大型底栖动物资源。根据调查文献,按中国海洋生物名录构建大型底栖动物种类名录,对大型底栖动物物种数、分类多样性指数、G-F多样性测度指数和相似性系数进行分析。结果显示,这6个重要列岛潮间带大型底栖动物物种数差异较大。其中,南麂列岛最高(330种),台州列岛最低(133种)。平均分类差异指数?+嵊泗列岛最高,达84.76,台州列岛最低,仅70.89,而分类差异变异指数?+值洞头列岛的最高,达846.94,嵊泗列岛最低,仅630.25。南麂列岛的G-F多样性测度指数最高,达0.87,这表明在科级分类阶元多样性(F指数)一定的前提下,属级分类阶元多样性(G指数)将会变高。科级和目级相似性结果显示,科级相似性最高的是洞头列岛与台州列岛,达0.651,渔山列岛与嵊泗列岛最低,仅0.480;目级相似性最高的仍是洞头列岛与台州列岛,达0.781,台州列岛与渔山列岛最低,仅0.623。本研究分析了浙江6个重要列岛潮间带大型底栖动物分类多样性,以期为浙江海岛潮间带大型底栖动物资源的养护、开发与管理提供科学依据。     

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。     

江苏中南部潮间带大型底栖动物时空分布特征

2013年5月(春季)、8月(夏季)、11月(秋季),对江苏中南部潮间带大型底栖动物进行了定性和定量调查。共采集到大型底栖动物68种,定量63种,定性19种,多毛类、软体动物以及甲壳动物是组成大型底栖动物的主要类群。优势种为文蛤(Meretrix meretrix)、泥螺(Bullacta exarata)、四角蛤蜊(Mactra veneriformis)、托氏虫昌螺(Umbonium thomasi)、加州齿吻沙蚕(Nephtys californiensis)、双齿围沙蚕(Nereis aibuhitensis)以及宽身大眼蟹(Macrophthalumus dilatatus)等。年平均总生物密度65.15 ind·m-2,平均总生物量94.21g·m-2。和历史资料比较后发现,自20世纪80年代至今,江苏中南部潮间带大型底栖动物生物量有增无减。大型底栖动物的生物密度、生物量、多样性和相对重要性指数随季节的不同而有所变化,其中生物密度、生物量以及多样性指数均以春季最高。江苏中南部潮间带大型底栖动物群落生物量优势度曲线位于丰度曲线上方,群落结构稳定性较高,未出现明显扰动。     

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....     

洞头列岛潮间带大型底栖生物的时空分布及其多样性

为了解洞头列岛潮间带大型底栖生物的时空分布特征及其多样性, 分别于2006年秋季(10月)和2007年春季(4月)对洞头列岛4个断面开展了春秋航次调查。共鉴定出大型底栖生物72种, 包括软体动物44种, 甲壳动物13种, 藻类11种, 多毛类2种, 棘皮动物1种, 其它动物1种。从季节来看, 虽秋季航次的物种数(66种)稍高于春季(63种), 但平均生物量和丰度却都是春季航次(分别为1 129.23 g/m2、707 ind/m2)明显高于秋季航次(分别为576.98 g/m2、461 ind/m2)。各断面主要优势种为疣荔枝螺、日本笠藤壶和粒屋顶螺等, 它们占总生物量和丰度的60%以上。从多样性指数来看, 洞头列岛物种多样性指数平均为1.73?0.47, 变化范围为0.83~2.10, 物种丰富度指数平均为2.26?0.33, 变化范围为1.99~2.95, 均匀度指数平均为0.62?0.19, 变化范围为0.29~0.85, 辛普森优势度指数平均为0.70?0.18, 变化范围为0.36~0.87。综合以上结果发现, 洞头列岛各断面潮间带大型底栖生物群落结构不稳定, 且物种多样性较差, 有向次生型群落结构演化的趋势, 主要原因是过度采捕、生境破碎等人为干扰过于严重导致的。     

日照近海大型底栖动物群落结构

2007年4月和10月,在山东日照临近海域进行了大型底栖动物春季和秋季两个航次的调查,对采集到的大型底栖动物进行分类鉴定。结果显示:1)全海域共鉴定底栖动物141种,其中多毛类、甲壳动物、软体动物分别占总种数的38.30%、34.75%和17.73%,三者构成大型底栖动物的主要类群。2)大型底栖动物的总平均丰度为1885ind/m2,总平均生物量为39.82g/m2。3)大型底栖动物种类多样性,春季高于秋季。4)优势种随季节变化不大,生物群落结构稳定性较好。     

胶州湾西北部潮间带冬季大型底栖动物丰度和生物量

为了解潮间带底栖动物的空间分布情况,根据2009年2月份在胶州湾西北部潮间带进行的7断面35个站位的底栖生物采样调查资料,分析了潮间带冬季大型底栖动物的数量分布。结果表明,调查共获得大型底栖动物49种,平均丰度88.1ind/m2,平均生物量77.8g/m2;主要优势种为菲律宾蛤仔(Ruditapes philippinarum)、缢蛏(Sinonovacula constricta)、凸壳肌蛤(Musculus senhousei)和日本大眼蟹(Macrophthalmus japonicus)。总体丰度在中潮区较高,生物量在低潮区较大;断面5丰度、生物量均最高,断面1丰度、生物量均最低。多毛类丰度和生物量在潮区间差异显著(P0.05),在中下潮区分布最多;甲壳类丰度和生物量在潮区和断面间差异均不显著(P0.05);软体类生物量在断面间的分布差异显著(P0.05),断面5最高,断面1最低。研究表明,大型底栖动物的种类组成、丰度与生物量的分布很不均匀,环境的复杂性和人为扰动可能是胶州湾西北部潮间带底栖动物分布不均匀的主要原因。     

黑龙江中游嘉荫至萝北段夏季大型底栖动物群落结构分析

为摸清黑龙江中游重要江段大型底栖动物群落结构和多样性的空间变化，于2022年6—7月(夏季)对黑龙江中游嘉荫至萝北江段及其附属支流的大型底栖动物进行采样调查，分析大型底栖动物群落的种类组成、生物量、丰度及多样性等指标，以阐明大型底栖动物群落结构的空间变化，并为水生生物多样性的调查与监测提供基础数据，为保护珍稀鱼类提供重要的饵料生物参考依据。结果表明：黑龙江中游嘉荫至萝北江段共有大型底栖动物4门42科84个种类，包括节肢动物门70种，软体动物门10种，环节动物门3种及扁形动物门1种，优势种为四节蜉(Baetis sp.)和透明高翔蜉(Epeorus pellucidus)。大型底栖动物总平均生物量为(1.06±1.72)g/m²，总平均丰度为(8.57±5.89)ind./m²。CLUSTER聚类分析结果显示，21个断面的大型底栖动物可划分为6组，存在极显著的空间差异(Global R=0.76,P<0.01)。SIMPER分析表明，引起黑龙江中游嘉荫至萝北段夏季大型底栖动物群落结构差异显著的主要种类为中华小长臂虾(Palaemonete...     

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.     

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.     

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.