崇明东滩南部大弹涂鱼食源的稳定同位素分析

利用稳定同位素技术,对崇明东滩南部湿地4、5月份采集到的大弹涂鱼(Boleophthalmus pectinirostris)的食源进行初步研究。结果显示,大弹涂鱼δ13C和δ15N值分别为-19.28‰~-14.59‰,7.96‰~10.13‰。利用同位素混合模型(Iso Source)计算包括白茅(Imperata cylindrical)、芦苇(Phragmites australis)、互花米草(Spartina alterniflora)、糙叶苔草(Carex scabrifolia)、底栖微藻、颗粒有机物和沉积质在内的7种初级生产者对大弹涂鱼碳源食源贡献的可能范围及分布频率,结果表明白茅、芦苇、互花米草、糙叶苔草、底栖微藻、颗粒有机物和沉积质对大弹涂鱼食源的可能贡献范围分别为0%~69%、0%~30%、0%~72%、0%~30%、0%~76%、0%~44%和0%~47%。利用后整合方法计算得到C_3植物(芦苇和糙叶苔草)、藻类及有机质(底栖微藻、颗粒有机物和沉积质)和C4植物(白茅和互花米草)三大类生产者对大弹涂鱼食源的贡献情况,结果表明C_3植物、藻类及有机质和C_4植物对大弹涂鱼春季食物贡献范围分别为0%~30%、0%~76%和24%~72%,中值分别为15%、38%和48%,表明C_4植物是大弹涂鱼不可缺少的食源。同时,根据大弹涂鱼的δ15N值,得出大弹涂鱼属于2.07~2.65级营养级,为次级消费者。     

桑沟湾常见温带海草叶绿素荧光特性的比较

2011年7～8月在桑沟湾楮岛南岸东部海域,利用水下调制脉冲式荧光仪(DIVING-PAM)原位测定了中国北方3种常见温带海草大叶藻、丛生大叶藻以及红纤维虾海藻的不同叶龄叶片的叶绿素荧光特性,并确定了几种海草的吸光系数(AF)和叶片叶绿素含量,计算出海草绝对电子传递速率.实验结果表明,叶龄对海草的光合活性有较大影响,同种海草的AF值和叶绿素含量都随叶龄增加而增加,叶龄小的叶片明显具有较大的最大电子传递速率(ETRmx)(大叶藻∶叶1=26.56,叶2=21.45,叶3=19.98;红纤维虾海藻叶1=22.31,叶2=19.23,叶3=17.06;丛生叶藻∶叶1=20.16,叶2=16.10;叶3=13.10).相比于丛生大叶藻和红纤维虾形藻,大叶藻具有最高的光合活性(ETRmax=22.67),这也与大叶藻在3种海草中所具有最高的初级生产力是相符合的.     

沙底池塘刺参养殖技术

近年来我国北方沿海刺参池塘养殖已成为渔业生产的支柱产业之一.刺参对底质环境的要求严格.研究表明,在硬泥沙或硬沙泥底质的池塘中养殖刺参的效果较好.底质组成中含粗砂及礁石多的区域,刺参分布密度大,生长快;而含细沙及泥量多的海域,刺参分布密度稀、生长慢.笔者在辽宁葫芦岛海滨附近养殖场进行了试验,结果发现沙底池塘刺参养殖效果较好,现将养参技术简述如下: 一、池塘条件 试验海区池塘为潮上带砂质底质.水源为近海直接纳潮.经过检测,海水的各项指标符合渔业生产用水标准.     

3种仿刺参养殖池塘底质特性的研究

为研究3种仿刺参养殖池塘底质的特点,于2014年4—6月检测了砂质底、泥沙质底和泥质底仿刺参养殖池塘底泥的粒度组成、7项理化指标及8类细菌数量特点。试验结果显示,3种池塘底质分别属于含砾泥质砂质底、粉砂质砂质底和砂质粉砂质底;底泥pH值波动均不大;氧化还原电位的变化范围分别为-336.83~-233.83mV、-340.77~-310.30mV和-380.66~-369.77mV;硫化物含量分别为29.64~386.83μg/g、47.6~507.50μg/g和160.16~991.04μg/g;砂质底池塘总氮、总磷、有机碳含量较少,泥沙质底总氮含量超标严重,泥质底总磷含量超标,且有机碳含量远高于其他两种底质池塘。3种底质池塘底泥中氨化细菌、反硝化细菌的数量均远高于亚硝化细菌的数量,还原性物质大量积累;泥沙质底池塘弧菌和硫还原细菌数量较多。结果表明,3种底质池塘底泥所存在的共性问题是底泥氧化还原电位偏低,硫化物含量较高;其差异性体现在砂质底池塘各指标波动较大,泥沙质底池塘总氮含量超标,有害细菌滋生,泥质底池塘底泥总磷含量超标,有机碳含量较高。     

人工鱼礁区的海草移植及其限制因子

2008年6-12月在深圳市杨梅坑人工鱼礁区开展海草的移植试验,第一批次开展了喜盐、川蔓藻的基地试验池移植试验,海草最大存活为20 d；第二批次进行了喜盐草和矮大叶藻的人工鱼礁区分水层移植试验,海草最大活时间为120 d,且表层的海草生长存活情况相对较好.依据海草存活状况结合原生长地和移植试验地的各种环境因子进行了限制因子分析,结果表明,海草对光照和溶氧的要求较高,不同的环境因子均可成为海草存活生长的限制因子.同时,作者还对人工鱼礁区海草移植需要的注意点进行了探讨,认为在人工鱼礁区选择海草移植地时,需考虑与生长地具备相似的底质以及相近的海洋环境（包括温度、盐度、pH值、溶氧、光照等）,一般水深不应超过2m,同时具备直接太阳光照射的地方；在海草的移植过程,尤其是初始阶段,需采取必要的保护措施为海草提供生长空间以及防止敌害生物的啃食.     

山东半岛大叶藻的抽样调查与鉴定

2011年8～10月对山东半岛大叶藻进行了调查研究,并对山东半岛大叶藻进行了分类鉴定.结果显示,山东半岛主要存在3种大叶藻科(Zosteraceae)种类,分别是大叶藻属Zostera的大叶藻Zostera marina L.、矮大叶藻Zostera japonica Ascherson & Graebner以及虾形藻属Phyllospadix的红须虾形藻Phyllospadix iwatensis Makino.其中,大叶藻分布广泛,莱州湾、俚岛、小石岛、楮岛、汇泉湾等地均发现有大叶藻存在,莱州湾地区大叶藻呈斑状分布,汇泉湾呈零星分布,俚岛、小石岛、楮岛地区呈片状分布;矮大叶藻分布较少,莱州湾地区呈斑状分布,广饶地区零星分布;红须虾形藻仅发现于青岛石老人海水浴场,呈斑状分布.调查还发现,山东半岛近海沿岸大叶藻海草场都存在不同程度的退化和破坏,除俚岛、小石岛、楮岛的大叶藻呈片状分布以外,其他地区的大叶藻均呈斑状分布或者零星分布.日照东港地区的海草场更是破坏严重,且本次调查范围内未发现大叶藻存在.     

桑沟湾楮岛大叶藻床区域菲律宾蛤仔的生态贡献

桑沟湾楮岛大叶藻(Zostera marina L.)床周边存在大量的底栖菲律宾蛤仔(Ruditapes philippinarum),为摸清菲律宾蛤仔的生理活动与大叶藻的相互作用,2016年5~7月,在菲律宾蛤仔和大叶藻集中分布区,评估了菲律宾蛤仔种群资源量,现场流水法测定了菲律宾蛤仔个体水平的摄食、代谢生理,围隔实验法探讨了种群水平蛤仔与大叶藻的相互作用。结果显示,桑沟湾楮岛大叶藻床海区菲律宾蛤仔的平均生物量为(572.00±20.23) ind./m2,大(壳长为3.50~4.10 cm)、中(壳长为3.00~3.50 cm)、小(壳长为2.00~3.00 cm)规格各占9.01%、43.60%和47.38%。菲律宾蛤仔的排氨率、耗氧率、滤水率、摄食率分别为(0.44±0.15)~(1.40±0.35) μmol/(ind.·h)、(0.21±0.02)~(0.33± 0.08) mg/(ind.·h)、(0.69±0.38)~(0.83±0.66) L/(ind.·h)和(2.57±0.41)~(3.41±0.68) mg/(ind.·h),且都随体重的增加而增大。围隔实验设有3个实验组(蛤仔组、大叶藻组和大叶藻+蛤仔组),1个空白组,每组3个平行(大叶藻30茎枝左右、蛤仔15个左右),实验进行4 h。研究表明,蛤仔组、大叶藻+蛤仔组和大叶藻组间的溶氧浓度存在显著差异(P<0.05);蛤仔组与其他3组的氨氮浓度存在显著差异(P<0.05);蛤仔组、大叶藻+蛤仔组与空白组的水体颗粒物浓度存在显著差异(P<0.05),大叶藻组与空白组差异不显著(P>0.05)。桑沟湾楮岛海区菲律宾蛤仔养殖面积约为0.5 km2,蛤仔每天可以过滤46 t海水中的悬浮颗粒物,并为大叶藻提供0.4 t的氨氮。本研究为深入揭示大叶藻海区菲律宾蛤仔的生态作用提供了基础数据。     

桑沟湾大叶藻海草床生态系统碳汇扩增力的估算

2010～2011年对桑沟湾楮岛海区大叶藻床的调查研究显示,其生物量年度变化为313.5～769.3gDW/m2,在夏季达到最高值;初级生产力年度内为2.0～6.4gDW/m2.d;总组织含碳量为35.5%;来自海草初级生产力的固碳贡献约为543.5gC/m2.yr。大叶藻附着植物生物量较小,年平均约为21.2g/m2,固碳贡献约30gC/m2.yr;作为菲律宾蛤仔增殖场,来自蛤仔的固碳贡献约63.15gC/m2.yr,此外,参照已有研究的数据,将来自草床捕获颗粒的碳贡献等计算在内,桑沟湾大叶藻床扩增固碳量为1180gC/m2.yr,总量达290MgC/yr。     

大叶藻种子萌发与幼苗培育、种植方法的初步研究

<正>海草(Seagrasses)是生活于热带和温带海域浅水中的单子叶植物。目前全世界共发现有海草约12属67种,在中国共分布有5科11属21种海草[1]。大叶藻(Zostera marina L.)作为海草的一个典型代表,生于潮间带和潮下带的浅海中,通常形成广大的群落—海草床。海草能完全生长于沉水环境,有很发达的根状茎,有稳定沉积物、稳定底泥、抵御风浪对近岸底质的侵蚀作用,同时海草的叶片可以捕捉悬浮     

加强刺参种质资源保护促进养殖业的健康发展

刺参养殖被业内人士称为海水养殖的第五次浪潮,据统计,山东省的养殖面积达36万亩,年产值70亿元人民币。如何使这个新兴产业健康持续发展,作为刺参原种场有义不容辞的责任。一、保证亲本质量山东省威海刺参原种场每年向各地提供育苗亲参1.5万尾~2万尾,基本满足了胶东半岛刺参人工育苗的需求。为了保证亲参的种质纯正,原种场专门建立了亲参暂养育肥区,每年有计划地从刺参自然保护区捕捞体重300g以上的个体做预备亲参,然后将其投放在暂养育肥区进行育肥促熟。亲参暂养育肥区建在近海内湾,面积30公顷,水深3m~8m,底质为沙泥和砾石底,大叶藻、马尾…     

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.