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1.
中国龙虾硒息习性的观察   总被引:1,自引:0,他引:1  
于1999年5月在集美大学水产学院海水养殖试验场进行了中国龙虾息习性的试验观察,结果表明,正常温度、盐度条件下,中国龙虾有隐匿穴居、昼伏夜出的栖息习性,喜欢栖息于紧身或身体易于找到依赖的水平洞穴中,并有同穴共居现象,低层洞穴的栖息率高于高层洞穴;温度低于12℃时,中国龙虾夜间也很少离穴活动,湿度低于8.6℃或高于34℃,盐度低于14.1或高于44.6时,中国龙虾都会逃离洞穴。  相似文献   

2.
黄姑鱼胚胎发育及其与温度和盐度的关系   总被引:1,自引:0,他引:1  
为研究温度和盐度对黄姑鱼(Nibea albiflora)胚胎发育的影响,作者观察了黄姑鱼受精卵的形态和胚胎发育过程。实验结果表明,温度18~28℃范围内,温度对孵化时间和初孵仔鱼有显著影响,对孵化率影响不大,24~28℃是黄姑鱼胚胎发育的适宜温度范围;盐度低于24时受精卵下沉,26~28内悬浮于水体中,盐度高于34时受精卵浮于水面;黄姑鱼胚胎发育的最适盐度范围26~32,盐度超过或低于其适宜范围时,孵化率明显下降或者幼虫畸形率明显增大。另外,根据其Q10值推算的胚胎发育的适宜水温与实验结果相似。  相似文献   

3.
中国龙虾生长特点及促生长途径的探讨   总被引:1,自引:0,他引:1  
蜕壳后新甲壳完全硬化之前是中国龙虾(Panulirus stimpsoni)个体蜕壳生长过程的延续,对中国龙虾正常快速生长具有重要意义。环境因子、营养条件对中国龙虾的蜕壳与生长具有显著影响。24-27℃是中国龙虾蜕壳生长的适温范围;盐度24-32适宜中国龙虾生长,最适生长盐度是28;在6种试验饵料中翡翠贻贝饲养中国龙虾效果最好,其次是杂虾、杂蟹、牡蛎,投喂杂鱼的中国龙虾蜕壳增长率和阶段生长率都很低;龙虾饲料中添加蜕壳素能够縮短蜕壳周期,实现蜕壳率和蜕壳增长率的同步增长。摘除眼柄也能促进中国龙虾的蜕壳与生长,电刺激等外源刺激则只能促进蜕壳,而不能加速中国龙虾的生长,甚至可能产生负面影响。中国龙虾生长存在种内性别间的差异,同等条件下雄性个体的蜕壳增长率高于雌性个体。  相似文献   

4.
本文在实验室条件下,研究了温、盐度与海湾扇贝稚贝迁移、生长及存活的关系。其适合生长的温、盐度范围分别为16~28℃和19~34,最适温度和盐度分别为22℃,31.2;适合存活的盐度范围为19~39,盐度低于11或高于43,稚贝死亡严重;适合存活的温度为10~28℃。本文同时对温、盐度与稚贝附着后的迁移行为的关系进行了探讨。  相似文献   

5.
在实验室条件下,研究了不同温度、光照强度和盐度对海柏(Polyopes polyideoides)果孢子的放散及附着的影响。结果表明:温度10~26℃的条件下,海柏果孢子均能够完成放散附着;18℃时,海柏果孢子放散附着速度最快且总量最大,而当温度低于5℃或者高于30℃时,海柏果孢子的放散附着受到抑制,几乎不放散附着;海柏果孢子放散附着的适宜光照条件为80?mol/(m2·s),光照强度过高时海柏果孢子的放散附着明显受到抑制;盐度为22~36之间利于果孢子的放散附着,当盐度低于8,高于40的时候,海柏果孢子由于受到了盐胁迫,几乎不放散及附着。  相似文献   

6.
大西洋浪蛤(Spisula solidissima) 生态习性的初步观察   总被引:2,自引:0,他引:2  
1998年10至1999年8月对大西洋 浪蛤 的生态习性进行详细观察结果表明,大西洋浪蛤 的生存温度为-1℃~30℃,以10℃ ~25℃范围较适,盐度范围为10.0~51.5,pH范围4~9。营埋栖生活,潜居砂质底,洞穴的 深度与贝类长度相当,依靠水交换滤取食物,饵料以各种小型浮游生物及有机碎屑为主,对 种类没有明显的选择性。  相似文献   

7.
为了确定斑点鳟(Oncorhynchus mykiss)发眼卵孵化的适宜温度、盐度条件,作者通过设置不同的孵化温度和盐度,研究了温度、盐度对斑点鳟发眼卵孵化的影响。结果表明,发眼卵孵化的适宜温度范围为8~16℃,孵化率都在(73.33±2.04)%以上,最适温度为10℃,孵化率达(87.77±1.23)%。温度高于24℃时发眼卵不能孵化。温度在6~22℃内,斑点鳟发眼卵孵化时间与温度成负相关关系。斑点鳟胚胎发育的平均积温值为343℃?d。发眼卵孵化的适宜盐度范围为0~15,孵化率都在(85.33±1.92)%以上,最适盐度为0,孵化率达(97±1.13)%。盐度高于15时的孵化率为0。盐度在0~15内,发眼卵孵化时间与盐度成正相关关系。  相似文献   

8.
本研究通过设置温度突变组(15°C、25°C、31°C)和盐度突变组(5、15、25、35),探讨了温度、盐度变化胁迫对海洋青鳉鱼(Oryzias melastigma)摄食行为及抗氧化生理的影响。结果表明,在温度为15°C和31°C(盐度为25)时以及盐度为5和35(温度为25°C)条件下,青鳉鱼摄食响应时间增长,摄食量、摄食效率和摄食成功率显著下降(P0.05)。超氧化物歧化酶(SOD)、过氧化氢酶(CAT)酶活性和丙二醛(MDA)含量在15—31°C时随温度增加先降低后增加。SOD酶活性31°C时第7天显著性低于对照组(P0.05)。MDA含量在15°C和31°C时在显著性高于对照组,第7天显著性升高(P0.05)。不同盐度处理组,SOD、CAT活性和MDA含量均随盐度增加先降低后增加,MDA含量在盐度为5和35时均显著高于对照组(P0.05)。综上,海洋青鳉鱼在盐度15—25,水温25°C条件下摄食及游动行为活跃,抗氧化活性最低,生长良好。当温度高于31°C或低于15°C;盐度高于35或低于5时胁迫对青鳉鱼摄食行为及抗氧化性造成明显影响。  相似文献   

9.
中国蛤蜊繁殖生物学的初步研究   总被引:1,自引:0,他引:1  
结合土池育苗的试验,对中国蛤蜊的繁殖习性和胚胎发育过程进行了研究。中国蛤蜊在山东省海阳市丁字湾海区的繁殖期为6~8月,7月下旬至8月上旬为产卵盛期。鲜出肉率的变化与性腺发育具有明显的相关性,产卵前达到最大,为45.3%。水温在20℃以上时性腺发育速度明显加快,23~24℃肥满度最大。可用阴干、流水或降低盐度等方法诱导其排放精卵,也可进行解剖受精。中国蛤蜊雌雄异体,个别雌雄同体。胚胎发育可在盐度18~30,温度20~28℃条件下进行,超过30℃则引起幼虫大量死亡。  相似文献   

10.
半滑舌鳎胚胎发育及仔鱼生长与盐度的关系   总被引:6,自引:0,他引:6  
就半滑舌鳎(CynoglossussemilaevisGünther)受精卵和早期仔鱼生长发育与盐度的关系作了初步探讨。受精卵在盐度低于25的海水中全部下沉,在高于29的海水中浮在水面,而当盐度在26~28.5之间时在海水中呈悬浮状态。受精卵孵化的最适盐度为25~35,此盐度范围内孵化率都可达88%以上,盐度低于20或高于40孵化率降低,初孵仔鱼畸形率升高。盐度对仔鱼生长有一定的影响:盐度在25~35时初孵仔鱼存活率最高,盐度32.5时生长最好;盐度30~32.5范围内刚开口仔鱼的存活率较高,生长最快;盐度低于20时变态期仔鱼的存活率与盐度高于25时没有显著差异(P>0.05),但两者体长存在显著差异(P<0.05)。盐度高于40或低于10会延滞胚胎发育速率,孵化时间在盐度低于10时会相对延长。  相似文献   

11.
Lobster impoundments are dammed coastal embayments utilised to hold American lobsters (Homarus americanus) before shipping to market. The impacts of lobster impoundments on the environment have not been previously studied. Here, the digestive functioning of American lobsters was examined to assess the quantity and quality (TVS, total volatile solids) of lobster faeces produced under the temperatures and feeding regimens these animals were subjected to during the impoundment period. Overall it was determined that quantity and quality of faeces did not differ among the experimental temperatures (5, 10, and 15°C), and that animals fed every 1–2 days produced greater quantity and quality of faeces than those fed every 3–18 days, or those animals fed less than every 18 days. As a first estimate of organic matter production in active lobster impoundments, it was calculated that a typical lobster impoundment produced 0.79 ± 0.35 (average ± 1 SD) g TVS m‐2 day‐1 during the impoundment period, equivalent to 3.11 ± 0.60% of the total weight of lobsters stocked into the impoundment. This level of organic matter production is below the level produced by other aquaculture operations, and that at which benthic impacts might be expected.  相似文献   

12.
Based on the assumption that depleted stocks would have recovered during a six-year layoff from fishing, trapping for deep-water spiny lobster Palinurus delagoae and slipper lobster Scyllarides elisabethae off eastern South Africa resumed in 2004 until 2007. A generalised linear modelling approach was used to investigate the effects of year, sampling area, depth, month and trap soak-time on catch and lobster size, and to construct standardised abundance indices. The renewed trapping rapidly reversed partially restored nominal catch rates. Fishing strategy changed from targeting spiny lobsters during the first months of each fishing season to targeting slipper lobsters during later months. Small spiny lobsters were abundant in the southern area, identified as a recruitment hotspot. Spiny lobster abundance and size in this area increased over four years of fishing, but conversely, large adult spiny lobsters predominated in the central and northern areas, where trapping depleted their abundance over time. The adult populations in the central and northern areas are upstream from the recruitment hotspot, and are presumably a source of larvae. Slipper lobster abundance peaked in 2005, remained relatively constant across areas, and increased with depth. Trapping for deep-water lobster is unlikely to be sustainable in its present form. However, the clear gradients in spiny lobster size and abundance by sampling area and depth provide a good framework for spatial management planning.  相似文献   

13.
American lobster (Homarus americanus) have a thick calcified cuticle, and do not exhibit rapid colour changes characteristic of other crustaceans. Thus, the plasticity of their coloration has been largely overlooked. Colour in lobsters is determined by the amount, location, and form of the carotenoid pigment astaxanthin, and it is possible for lobsters to alter colour by changing one of these characteristics of astaxanthin deposition. Here, short‐term colour variation in American lobster in response to environmental cues (background colour and ultraviolet (UV) light) was investigated in a laboratory experiment. Lobsters were reared in conditions controlling background colour (white, black) and UV light (present, absent). Digital photographic analysis was used to determine how these conditions influenced the luminescence (light or dark) of lobster colour, as well as the ratio of red to blue hues. Of the environmental variables considered within this experiment, UV light was the predominant factor, and caused lobsters to become darker in colour. In the absence of UV light, lobsters matched background colour, and turned darker in response to the darker background. Environmental matching has practical implications both for wild lobsters as they settle to the benthic habitat, and for enhancement programmes, to grow lobsters that are best suited for local habitats.  相似文献   

14.
Any attempt to enhance rock lobster production by increasing survival after settlement, or by ongrowing or outplanting young juveniles, requires knowledge of the shelter preferences of young juveniles. For juvenile Jasus edwardsii in the wild these are not well known. Information available suggests that juveniles up to c. 35 mm carapace length (CL) occupy shelters that generally conform closely to their body dimensions but that larger juveniles use shelters of more variable dimension, often much larger than their body size. We investigated mainly physical factors important in shelter choice by 15–59 mm CL (c. 2–24‐month‐old juveniles) in laboratory tank experiments. In overnight tests, all sizes of juvenile lobster chose to occupy holes (shelters with sides) over open horizontal gaps. Preference for open horizontal gaps versus horizontal crevices (where the height reduces from a maximum at the mouth to zero at the opposite end) was much less clear‐cut; choice varied according to lobster size. For the number of entrances into holes, there was evidence for an ontogenetic shift in preference, small lobsters preferring two openings over one, whereas those >30 mm CL (c. 9 months old) preferred one over two. For lobsters <40 mm CL, the hole size and gap size preferences revealed were generally consistent with the field evidence for J. edwardsii in that there was a close and proportional relationship between lobster size and shelter size; what differed was that the open gaps chosen in the tanks by the smallest lobsters (15–19 mm CL) were larger than the holes used in the tank experiments and 30–50% larger than those reportedly used in the field. For lobsters >40 mm CL, the holes and gaps chosen in the tanks were generally larger and more variable in size, as in the field.  相似文献   

15.
During the 1990s the rock lobster Jasus lalandii shifted its focus of distribution south-eastwards along the coast of South Africa, to establish a dense population in an area where it was previously rare. This coincided with a marked decrease in the sea urchin Parechinus angulosus, a preferred prey item of J. lalandii and a vital source of shelter for juveniles of the abalone Haliotis midae. The range expansion of lobsters has thus economic and ecological ripple effects. We determined the diets of small (50–65 mm carapace length) and large (>69 mm CL) rock lobsters from gut content analyses, and compared them between three ‘lobster invaded’ sites and three adjacent ‘non-invaded’ sites where densities are still low. At the non-invaded sites, diets were collectively heterogeneous but the dietary breadth of individual lobsters was narrow (in contradiction to generally accepted ecological theory), and the lobsters fed mainly on large, individual, mobile, high-energy prey such as sea urchins and large winkles. Conversely, at invaded sites where lobster densities were high, they consumed predominantly small, colonial or sessile low-energy prey such as sponges, barnacles and foliar algae, and the diet was significantly more uniform among individuals, but broader within individuals. This was a direct result of the contrasting benthic community structure of the two areas, and consequent prey availability – itself caused by differences in intensity of rock-lobster predation. Cannibalism was unexpectedly greater at non-invaded sites, possibly as a result of lobsters being larger there. The diet of small and large lobsters also differed significantly. Large rock lobsters predominantly consumed large individual prey such as lobsters, urchins and crabs, while small rock lobsters ate mainly colonial, sessile prey such as sponges and barnacles, and small prey such as tiny winkles and crustaceans. Dietary selectivity indices revealed that algae and sponges were negatively selected (avoided) in non-invaded areas but positively or neutrally selected in invaded areas. These dietary differences have important ramifications not only for the lobster populations but also for the structure and functioning of the radically different communities that have developed in invaded areas, reflecting a regime shift induced by lobster predation.  相似文献   

16.
A study of inorganic iodine speciation in the waters of seven Croatian coastal caves is described. These are anchialine caves as they are connected hydraulically with Adriatic Sea surface water, with the tide inside the cave rising and falling with that outside, but replenishment of the water is restricted by the karst rock. In effect, the water in the cave probably acts more like a piston, and although moving slightly vertically, has a long residence time compared to a fully-flushing cave. Anchialine environments display a number of unusual features, e.g., a well-developed pycnocline, hypoxia and endemic fauna. Iodate and iodide were determined by differential pulse voltammetry and cathodic stripping square wave voltammetry, respectively. Low iodide concentrations (< 10 nM) have been consistently identified in the bottom water of the caves where concentrations of 90–100 nM would ordinarily be expected from intrusion of Eastern Adriatic surface seawater. Where total inorganic iodine concentrations behave conservatively with salinity the loss of the iodide implies oxidation to iodate. As iodide oxidation remains one of the enduring academic problems of the marine iodine system the study of iodine in anchialine caves may help unravel it. Iodate reduction was observed in mid-water, at the halocline, and mechanisms for the reduction involving either respiration or chemolitho-autotrophic bacteria are considered. The respiration mechanism is favoured because of enhanced alkalinity found in the near surface waters of the caves.  相似文献   

17.
Southern rock lobster Jasus edwardsii varies in shell coloration throughout southern Australia. Predominantly exported as a live product to Asian markets, price is influenced by colour with prices higher for dark red than paler coloured lobsters, which are discounted. This paper explores spatial and depth variation in shell colour for the Tasmanian, South Australian and Victorian fisheries using catch sampling data. The proportion of red lobsters decreased with depth and was prevalent at depths less than 30 m, whereas paler coloured lobsters dominated the deeper depth ranges. The depth of transition where 50% of lobsters were classified as red showed a weak trend of increase with latitude from southern Tasmania to northern South Australia. Under quota management, lobster colour was a significant driver of fleet dynamics as fishers target areas of high price per unit. Consequently, catches of pale lobsters from greater depths remain low despite the high catch rates in these areas. The colour price differential varies seasonally (higher in summer) so fishers increase supply of pale lobsters during winter. Discounting on colour equates to AUS$6.67 million/year for the Tasmanian Fishery alone, which indicates value from management or marketina research to reduce discountina.  相似文献   

18.
Instances of morbidity amongst rock lobsters (Panulirus cygnus) arriving at factories in Western Australia (WA) have been attributed to stress during post‐harvest handling. This study used discriminant analysis to determine whether physiological correlates of stress following a period of simulated post‐harvest handling had any validity as predictors of future rejection or morbidity of western rock lobsters. Groups of 230 western rock lobsters were stored for 6 h in five environments (submerged/flowing sea water, submerged/recirculating sea water, humid air, flowing seawater spray, and recirculated seawater spray). The experiment was conducted in late spring (ambient sea water 22°C), and repeated again in early autumn (ambient sea water 26°C). After 6 h treatment, each lobster was graded for acceptability for live export, numbered, and its haemolymph was sampled. The samples were analysed for a number of physiological and health status parameters. The lobsters were then stored for a week in tanks in the live lobster factory to record mortality. The mortality of lobsters in the factory was associated with earlier deviations in haemolymph parameters as they emerged from the storage treatments. Discriminant analysis (DA) of the haemolymph assays enabled the fate of 80–90% of the lobsters to be correctly categorised within each experiment. However, functions derived from one experiment were less accurate at predicting mortality when applied to the other experiments. One of the reasons for this was the higher mortality and the more severe patho‐physiological changes observed in lobsters stored in humid air or sprays at the higher temperature. The analysis identified lactate accumulation during emersion and associated physiological and haemocyte‐related effects as a major correlate of mortality. Reducing these deviations, for example by submerged transport, is expected to ensure high levels of survival. None of the indicators tested predicted mortality with total accuracy. The simplest and most accurate means of comparing emersed treatments was to count the mortality afterwards.  相似文献   

19.
A laboratory experiment was conducted to investigate the transfer of organic contaminants from an environmentally contaminated marine sediment through a simple marine food chain. The infaunal polychaete, Nereis virens, was exposed to contaminated sediment collected from the Passaic River, NJ, USA, for 70 days. These polychaetes were then fed to the American lobster, Homarus americanus, for up to 112 days. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), 2,4,6,8-tetrachlorodibenzothiophene (TCDT), polychlorinated biphenyls (PCBs), and several chlorinated pesticides were accumulated by polychaetes following exposure to the contaminated sediment. Some of these contaminants were also accumulated by lobsters which were exposed to the contaminated sediment and/or fed contaminated polychaetes. Only the lesser chlorinated PCDDs and PCDFs (mostly tetra- and pentachlorinated congeners) and 2,4,6,8-TCDT were detected in the polychaetes and lobster. Significant alterations were noted in the PCB patterns found in both species, particularly the lobster. The non-ortho-substituted PCBs (such as congeners 77 and 126) became enriched in the PCB mixtures of the polychaetes and especially the lobsters relative to the sediment, probably because these congeners were not metabolized. These congeners and the 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalents of the PCB mixtures were enriched by a factor of about six in the lobsters relative to the sediment. Elimination of PCB congeners containing vicinal hydrogens in the meta-para region is consistent with cytochrome P450IIB-type metabolism. Based on the concentration trends for some PCB congeners and chlorinated pesticide ratios measured in the lobsters during this experiment, it appears that this metabolic system is inducible in the American lobster.  相似文献   

20.
The California spiny or red rock lobster, Panulirus interruptus, is an ecologically and economically important species that has been exploited since the 1800s. No previous study in California has assessed the impacts of the recreational or commercial lobster harvest. Before the 2003–04 commercial and recreational lobster seasons, we conducted a fishery‐independent trap survey at Santa Catalina Island to document the impact of the lobster fisheries on the size structure, abundance, and sex ratios of mature P. interruptus (>65 mm carapace length (CL)). We concurrently sampled a predominantly commercially fished area, a recreationally fished area, and a 23‐year‐old invertebrate no‐take (INT) reserve. Relative to the INT reserve, legal‐size lobsters in the recreational area were similar in CL, but 31% less abundant. Legal‐size lobsters in the commercial area were 8% smaller and 70% less abundant than those in the INT reserve. The sex ratio of legal‐size lobsters, although near 50:50 in the recreational and INT reserve areas, was male‐dominated (67:33) in the commercial area. Differences in CPUE and mean CL of sub‐legal lobsters in the recreational and commercial areas suggest that factors in addition to harvesting pressure may affect these populations. Total biomass of mature lobsters in the recreational and commercial areas was 92% and 45%, respectively, of biomass in the INT reserve. Fecundity in the recreational and commercial areas was 83% and 42%, respectively, of fecundity in the INT reserve. This study provides preliminary data for future ecological studies and fisheries management evaluations.  相似文献   

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