基于灰色系统理论的网箱养殖大黄鱼Pseudosciaena crocea (Richardson)疾病预报

为预报网箱养殖大黄鱼细菌性疾病的发生,以舟山市网箱养殖大黄鱼为研究对象,根据2001—2008年间舟山市网箱养殖大黄鱼发病情况的监测数据和各采样点海洋环境因子的测定数据,应用灰色系统理论探索了网箱养殖大黄鱼细菌性疾病的发生发展规律及其与环境因子的关系;建立了灰色预报模型GM(1,1)和GM(1,N),预报网箱养殖大黄鱼细菌性疾病的发生时间和发病率。灰色关联分析结果表明,大黄鱼细菌性疾病的发病率与养殖水域的环境因子都有不同程度的关联;把水温、悬浮物、无机氮和COD选作先行指标,用这些因子的不同组合建立了GM(1,5)、GM(1,4)和GM(1,3)模型,比较这些模型的平均相对误差,由无机氮和COD构成的GM(1,3)模型平均相对误差最小,为5.304%;用GM(1,1)模型对大规模细菌性疾病发生的时间进行了预测,预测结果与实际情况基本一致。     

网箱养殖大黄鱼溃疡病的预报模型

本文以舟山市网箱养殖大黄鱼Pseudosciaena crocea (Richardson)为研究对象，根据对2001-2005年间网箱养殖大黄鱼发病情况的观察分析、养殖水域环境因子的监测及其收集的气象资料，对大黄鱼溃疡病的发生规律和养殖环境的状况进行了全面分析，结果表明大黄鱼溃疡病的发生不仅与季节有关，而且还与环境因子的状况密切相关。在此基础上，进一步研究了环境因子对大黄鱼溃疡病发生的影响程度和影响方式，筛选出与大黄鱼溃疡病发生密切相关的环境因子，从而建立了网箱养殖大黄鱼溃疡病发生的预报模型。经检验该模型对预报大黄鱼的溃疡病是否发生及发生的程度有高度显著的效果，用该模型对舟山市2005年大黄鱼溃疡病的发生情况进行了预报，预报的正确率达到81.2%。为能有效、适时地对发病季节大黄鱼疾病的控制，本文还同时给出了网箱养殖大黄鱼发病季节溃疡病的预报模型。     

灰色拓扑模型在海州湾人工鱼礁区水质预测的应用

该研究分别采用残差修正的GM(1,1)模型和灰色拓扑预测方法对2007—2017年春(5月)、秋(10月)海州湾人工鱼礁区的溶解氧(DO)、化学需氧量(COD)、生化需氧量(BOD5)及溶解无机氮(DIN)4个指标的监测数据建立水质预测模型并选择精度较高的模型预测2018—2022年的水质变化趋势,最终利用2018年的调查数据对预测结果进行检验。结果表明,灰色拓扑模型相较于残差修正的GM(1,1)模型针对水质数据具有更好的预测精度,预测结果与2018年的调查结果较吻合,可信度较高;预测结果显示,DO和COD在2018—2022年能够保持良好的水质状态,可见人工鱼礁建设对海域水环境状况具有一定的修复作用,但BOD5和DIN存在一定的超标风险;针对灰色拓扑模型的改进仍具有很大的研究空间,有待进一步挖掘。     

海带对大黄鱼网箱养殖区水质的生物修复

为构建大黄鱼生态养殖模式,通过开展海带-大黄鱼间养试验,研究了该养殖模式下海带对大黄鱼网箱养殖区富营养化海水的生物修复效果。通过对生物修复区、非生物修复区和非养殖区的连续定时和定点监测,结果表明间养海带对大黄鱼网箱养殖区的富营养化海水具有明显的修复作用。经过28 d的连续监测,生物修复区的溶解氧(DO)浓度明显高于非修复区,无机氮(IN)、无机磷(IP)浓度均低于非修复区,同时生物修复区的化学耗氧量(COD)达到非养殖区的水平。因此,海带-大黄鱼的生态间养模式能有效降低富营养化水体中的IN和IP,并显著提高DO浓度,改善水质,这将为大黄鱼的健康生态养殖提供参考。     

象山港内新增网箱养殖污染物对海水水质的影响预测

象山港是宁波市最重要的网箱养殖港湾,网箱养殖带来丰厚经济利益的同时,也产生了大量的养殖污染物。文章以象山港内某新增大黄鱼网箱养殖基地为例,利用Deflt3D二维对流扩散模型预测养殖废水中的污染物对海水水质的影响。结果表明,新增大黄鱼网箱养殖产生的三种污染物浓度增量均是在网箱养殖点较高,在网箱养殖区外污染物随潮流运动迅速扩散,浓度增量降低,由于本项目规模小、时间短,其产生的养殖污染物对象山港水质的影响不大。但是,由于象山港内活性磷酸盐和无机氮已超标,对新增网箱养殖仍要严格评估其污染物排放浓度,以切实保护象山港海域环境,促进该海域养殖业的可持续发展,本文研究结果可为新增网箱养殖污染物预测提供参考。     

基于优化灰色模型的南海鸢乌贼资源丰度预测

鸢乌贼(Sthenoteuthis oualaniensis)是南海重要的经济头足类之一,巨大的开发潜力与经济价值使其在我国南海海洋渔业中的地位日益凸显。为深入了解南海鸢乌贼单位捕捞努力量渔获量(Catch per unit effort, CPUE)变化情况并作出科学预测,文章选择构建灰色预测模型GM (1,N),结合海洋环境因子,对2013—2019年春夏季南海鸢乌贼生产数据进行拟合预测,使用Simpson公式和Fourier级数改造原模型背景值并对拟合值残差做修正。结果显示,在鸢乌贼CPUE预测上,普通GM (1,N)模型的平均相对误差为7.78%,优化灰色GM (1,N)模型为2.54%;在2019年鸢乌贼CPUE预测上,优化灰色GM (1,N)模型将相对误差从普通GM (1,N)模型的4.79%降至1.87%。结果表明,优化的灰色模型较普通多因素GM (1,N)模型的预测精度更高,为准确预测鸢乌贼资源相对丰度提供了一种新思路。     

网箱饲养的大黄鱼病害防治

福建省闽东地区开展大黄鱼网箱养殖有10年了 ,至今全省大黄鱼养殖网箱已发展到2 0余万只 ,成为浅海养殖的龙头产业。近年来 ,由于网箱集中连片 ,布局不合理 ,海区水域环境有机质负荷急剧增大 ,呈现富营养化趋势 ,造成网箱饲养的大黄鱼大面积发病 ,且鱼病种类多、发病率高、危害大 ,对这一新兴的养殖业健康稳定发展起着严重的阻碍作用。因此 ,加强对大黄鱼病害防治技术的研究已刻不容缓。现就其主要病虫害的防治技术阐述如下。一、细菌性疾病1.弧菌病病原　　弧菌症状　　体表溃疡为其典型特征 ,随环境条件、感染途径的不同而有差别 ,并常有…     

基于灰色系统的北太平洋柔鱼渔汛特征分析及旺汛期预测

柔鱼(Ommastrephes bartramii)是大洋性经济头足类,是我国远洋鱿钓渔船重要的捕捞对象。分析柔鱼渔汛特征并预测旺汛期,有助于柔鱼资源的合理开发与利用。本研究根据2013―2017年北太平洋柔鱼渔业生产统计数据,以每日平均渔获量(CPUEday)作为资源丰度,利用分位数的方法划分旺汛期;结合灰色波形预测方法,对旺汛期日期序列建立灰色波形预测模型群[GM(1,1)模型],对旺汛期出现的时间进行预测。结果显示,北太平洋柔鱼渔汛时间最早为5月12日,一直持续到年终;旺汛期为每年的8―11月,第1旺汛期基本在8月出现。GM(1,1)模型的平均相对误差为6.83%,旺汛期日期序列预测的平均相对误差为8.19%,验证数据的平均相对误差为15.82%,表明此模型可预测北太平洋柔鱼的旺汛期。研究结果可为远洋渔业企业的高效率、合理化的科学生产提供技术支撑。     

海水网箱养殖大黄鱼烂尾病的防治

据调查，舟山地区网箱养殖大黄鱼主要病害是烂尾病(即细菌性体表溃疡病)，本文对大黄鱼烂尾病的发病原因进行分析，并提出防治对策。     

深水网箱养殖病害综合防治技术

深水网箱养殖因集约化程度高、养殖密度大、单位水体产量高、产品质量高和经济效益显著等特点而备受瞩目。然而随着养殖生产的发展，深水网箱养殖的鱼类也出现了病害。根据2003年浙江省水产病害测报信息，部分地区深水网箱养殖的大黄鱼已不同程度地发生了细菌性疾病和寄生虫病，虽然对养殖生产造成的影响和损失并不大，但已经为深水网箱养殖的病害防治敲响了警钟。     

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.