An 11-ketotestosterone induced kidney-secreted protein: the nest building glue from male three-spined stickleback, Gasterosteus aculeatus

In male three-spined sticklebacks, Gasterosteus aculeatus, the kidney hypertrophies during the breeding season and produces a glue which is used in nest-building. This hypertrophy is androgen dependent with 11-ketotestosterone (11 KT) being most effective. The aim of the present study was to characterize the protein composition of this glue. Threads of glue were collected from stickleback nests and glue material was sampled from the content of urinary bladders of male sticklebacks in breeding condition. The samples were investigated using sodium dodecyl sulphate- polyacrylamide gel electrophoresis (SDS-PAGE). One major glycoprotein dominated in both the nest-threads and urinary bladder samples. The identified glycoprotein had a molecular mass of approximately 203 kDa. After deglycosylation the molecular mass was approximately 200 kDa. The amino acid composition of the protein from urinary bladder content was almost identical to the amino acid composition of the protein from the nest-threads. The protein had a relatively high content of cysteine (7.6–8.0%). The glycoprotein was named spiggin. Spiggin was absent in the urinary bladder of untreated castrated fish, but spiggin was present in sham- operated fish and in castrated fish treated with 11 KT. These results demonstrate that spiggin is induced by 11 KT. Spiggin is so far the only protein known to be induced by 11KT and based on the present findings we suggest that spiggin represents a novel structural protein.     

LH-β and FSH-β mRNA expression in nesting and post-breeding three-spined stickleback, Gasterosteus aculeatus, and effects of castration on expression of LH-β, FSH-β and spiggin mRNA

The mRNA expression of the LH- and FSH- subunits were measured in nesting and post-breeding male three-spined sticklebacks, Gasterosteus aculetaus, as well as in castrated and sham-operated nesting males. Furthermore, expression of an androgen induced kidney protein, spiggin, and 11-ketotestosterone (11KT) levels, were measured in the castrated and sham-operated males. Nesting males had significantly higher levels of both LH- and FSH- mRNA expression compared to post-breeding males. Furthermore, sham-operated males had significantly higher levels of LH- mRNA and spiggin mRNA expression than the castrated fish. Expression of FSH-, on the other hand, did not differ between castrated and sham-operated males. There were strong positive individual correlations between circulating levels of 11KT on the one hand and expressions of LH- and spiggin mRNA, whereas the correlation between 11KT levels and FSH- mRNA was weak. The negative effect of castration on -LH mRNA indicates that gonadal hormones stimulate this expression, whereas this was not the case for -FSH. The observed decline in -LH expression after the end of the breeding season may be the result of cessation of the gonadal stimulation of the pituitary. On the other hand, it is not likely that this can explain the decline in FSH- expression.     

许氏平鮋消化道中部分消化酶的研究

对许氏平 (Sebastesschlegeli)消化道内的 5种与消化吸收有关的酶进行分布和活性测定。结果表明 ,(1)肠道各段均具很高碱性磷酸酶活性 ,最适 pH为 9.7。食道和胃几乎没有碱性磷酸酶活性。 (2 )消化道各部位均含酸性磷酸酶 ,肠道活性最高 ,自幽门盲囊起依次递降。食道和胃酸性磷酸酶活性明显低于肠 ,胃和肠酸性磷酸酶的最适 pH均为 5 .3。 (3)肠道中羧酸酯酶活性明显高于胃 ,且 2者羧酸酯酶最适 pH差别较大 ,分别为 8.4和 6 .8。(4)胃蛋白酶活性明显高于肠道 ,胃蛋白酶最适pH为 2 .6 ,肠蛋白酶最适 pH为 9.4。 (5 )胃淀粉酶活性明显低于肠道 ,胃淀粉酶最适 pH为 4 .6 ,肠道淀粉酶最适pH为 7.0。这表明许氏平对蛋白质的初步消化在胃中进行 ,在肠中进一步消化和吸收 ,而对糖类和脂类的消化和吸收主要在肠道进行     

鳔器官的发育对人工培育鱼苗的影响

论述了鳔器官的发育对海水鱼类人工培育苗种的影响，仔鱼期鳔的形成和充气是影响闭鳔海水鱼类人工育苗成效的重要因素之一，鳔发育异常一是导致仔稚鱼死亡，二是导致脊柱前凸。在人工养殖条件下，影响海洋闭鳔鱼类鳔器官充气的因子有营养因子和环境因子，充气量，水表面的油膜，温度，盐度和光照等环境因子影响仔鱼水表面吞饮空气，影响鳔的充气率，仔鱼摄食EPA和DHA含量低的饵料后，活力差，仔鱼到达水表面吞饮空气的能力下降，鳔的开腔率降低，此外仔鱼体内甲状腺素的含量可能对仔鱼鳔的开腔率产生影响。     

氮、磷营养盐组成对铜绿微囊藻生长的影响

应用室内培养实验方法研究了不同组成氮盐(TN)和磷盐(TP)对铜绿微囊藻生长的影响。结果表明,铜绿微囊藻的生长状况很好地符合Logistic生长模型,进一步研究表明,铜绿微囊藻存在营养盐生长阈值CTP、CTN,分别为1.8mg/L和25.0mg/L,当TP、TN的初始浓度分别小于CTP和CTN时,随其初始浓度的增加会促进铜绿微囊藻的生长,但当初始浓度大于营养盐生长阈值时,随营养盐初始浓度的增加反而会逐渐限制其生长,表明铜绿微囊藻存在一个适宜生长的(TN∶TP)最佳值,为TN/TP=14∶1。     

Managing translocations of aquatic species

The translocation of aquatic organisms is an issue of increasing concern. In assessing the genetic risks from translocations, a primary distinction should be made between translocation for the purpose of aquaculture and translocation for the purpose of stock enhancement. When translocation is for aquaculture, the question of interest is: what is the maximum level of escapes that should be permitted, beyond which there is an unacceptable probability of adverse genetic effects upon the natural population? Risk minimization should concentrate on management solutions that reduce escapes from aquaculture facilities. When translocation is for stock enhancement, the question of interest is: what is the maximum level of genetic differences between hatchery and wild stock that should be permitted, beyond which there is an unacceptable probability of adverse genetic effects upon the natural population? Risk minimization should concentrate on hatchery management procedures that reduce genetic differences in fitness traits between hatchery stock and wild stock from the proposed recipient population. Where translocation poses a significant risk of adverse genetic changes, then a monitoring programme should be put in place, linked to a policy that prescribes management actions for the range of possible outcomes from the monitoring. The main limitation to our ability to develop an effective risk assessment and monitoring process is our lack of understanding of how the interaction between genetically different stocks affects the genetic basis of quantitative fitness traits that adapt organisms to their local environment.     

低盐度胁迫不同时间对褐牙鲆幼鱼生长的影响

将驯养于海水盐度为19的褐牙鲆（Paralichthys olivaceus）幼鱼放入盐度为5的海水中胁迫0周（对照）、1周、2周、3周和4周后,立即将海水盐度调节至19,养殖到第10周,观察幼鱼的生长情况。研究发现,低盐度海水养殖的褐牙鲆幼鱼体质量仅在低盐胁迫的第1周内显著小于对照组,不同处理的日生长系数在第3周与第5周呈现显著性差异,其余时间阶段内不同处理的体质量和日生长系数未见显著差异。胁迫阶段褐牙鲆幼鱼摄食率整体上略低于对照处理,但恢复阶段摄食率未出现大于对照处理的一致趋势。整个试验期间经低盐度处理的褐牙鲆幼鱼饲料转化效率略大于对照处理。试验结果显示,低盐度5对褐牙鲆幼鱼的生长没有产生长期影响,也不能通过较长时间的低盐度养殖引起褐牙鲆幼鱼的补偿生长效应。     

美国青蛙膨气病病原菌的分离鉴定及药敏试验

经对膨气病病原菌的分离鉴定，嗜水气单胞菌与假单胞菌属细菌是致病菌。药敏试验结果：庆大霉素，氯霉素对致病菌有较强的杀灭作用，中草药黄连，黄岑也有一定的抑制作用，该病发生与环境条件密切相关，保持良好的养殖水质环境是预防该病的最好方法。     

白颊噪鹛消化系统形态的初步研究

白颊噪鶥消化系统的形态学初步观察与研究,结果表明:白颊噪鶥舌呈长三角形,舌尖分叉呈"V"字型,粘膜上具有尖端指向后方的栉状突;食道颈胸分段不明显,食管全长43.33mm,食管与嗉囊分界不明显;腺胃上圆形乳突少而稀,肌胃发达;肠几乎与体长相等,小肠较发达,雄鸟约长182.8mm,占肠道总长88.8%;雌鸟约长196.38mm,占肠道总长88.6%;具有左右侧盲肠,占肠道总长4.87%;直肠占肠道总长6.4%;肝分左右两叶;胰细长形,分两小叶。这些消化道特征说明白颊噪鶥是以食虫为主的杂食性鸟类。     

The Use of Anglers'Returns in the Estimation of Fishing Success

The method of collation of angling results at Ffestiniog fishery is described. Rod averages calculated from returns are always higher than those assessed by the fishery bailiff. Two studies indicated that, although there is no reason to question the veracity of returns, those received represent a sample of anglers which is biased towards the more successful. The care needed in extrapolation from angling returns is emphasized and it is demonstrated that only the bailiff's estimates of fishing success lead to sensible estimates of the seasonal catch.     

草鱼出血病的免疫学研究进展

由于草鱼病毒性出血病发病率高,且尚未找到有效防治的药物,至今一直成为草鱼养殖发展中"瓶颈"问题的根本原因。因此,采取免疫学途径防治草鱼出血病是解决此问题的关键之所在。综述了采用草鱼出血病疫苗、干扰素及免疫增强剂进行草鱼出血病防治的研究现状;提出口服型免疫增强剂是生产上防治草鱼出血病最为有效的途径之一。     

松浦银鲫形态学特征及主要经济性状

松浦银鲫主要形态学性状：体高／体长比为42．6％，头长／ 体长比为26．7％，体厚／体长比为20．3％，尾柄长／体长比为12．7％，尾柄高／体长比为16．8％，背吻距／体长比为49．9％，背尾距／体长比为56．2％，体厚／头长比为76．4％。侧线鳞数和侧线至背鳍基部及侧线至腹鳍基部的鳞片数为327／7，第一鳃弓左鳃耙数为50．5个，体背部青灰色，体侧淡绿色，腹部姜黄色。上述指数除头长／体长比外，都与方正银鲫明显不同，而细胞遗传学特征与方正银鲫相同，群体中雄性极少，为雌核发育群体。松浦银鲫个体较大，生长较快，一龄鱼稍快于方正银鲫，体重30克以上；二龄鱼体重约160克。群体生产力，在与鲤、链等鱼混养情况下，亩产30－45公斤。由于松浦银鲫体高较高，1－3龄鱼的肥满系数明显高于方正银鲫，鱼肉营养成份中，粗脂肪在鲜肉（3．6％）和干肉（14．8％）中都明显低于正方银鲫， 这是松浦银鲫的一个极有价值的指标。松浦银鲫和方正银鲫一样繁殖力极强，2龄极能成熟和繁殖，因此其生产能力很大。     

A description of four types of otolith opaque zone

Analysis of the alternating opaque and translucent zones in fish otoliths is a widely used method to determine age in fish. The mechanisms underlying the annual periodicities in the formation of these zones remain unknown, although various interpretations and explanations have been presented to explain the appearance of the opaque zones. Here I review the biological and structural characteristics of the opaque zones in otoliths from a number of fish species. The results of this review suggest that the opaque zones can be classified into four different types. Type A is a dark opaque zone, displaying minute, dense crystals, and is typically formed at a young life-history stage. Type B comprises an aggregation of grooves and discontinuous crystals that are formed during growth-stagnant periods. Type C can be described as a washy black zone that has the appearance of an object that is smeared with ink; it is formed during seasons of active growth. Type D has deep grooves, appears luminous in transmitted light in etched otolith sections, and is formed during the spawning season. Types A and C otolith opaque zones are typical of younger fish and are formed during growing periods. They are complementary to Types B and D otolith opaque zones which are formed during periods of stagnant growth and/or during the spawning seasons and which are typical of older fish, which generally lack Type A zones. To ensure precise age determination in fish, it is therefore necessary to understand the structural and biological characteristics that produce these four distinct types of opaque zones.     

Further studies of an epizootic of perch Perca fluviatilis L., of uncertain aetiology

Abstract. The geographical distribution of an epizootic of perch Perca fluviatilis L., characterized by severe epidermal lesions and marked fish kills, is described. A wide variety of fungal and bacterial infections were found in diseased fish but the evidence suggests that they were not the primary cause of this condition. The primary pathogenic agent (assuming that it exists) or predisposing environmental factor has yet to be discovered. The severity of this disease is illustrated by monitoring the course of the epizootic in the perch population in Windermere. All age groups of fish were affected during the course of one year although the fish at spawning time appeared to be particularly vulnerable. There was a dramatic increase in the perch mortality in Windermere in 1976 and it is estimated that over 98% of the adult population (over 1 million fish) died in that year.     

The consequences of density-dependent individual growth for sustainable harvesting and management of fish stocks

Density dependence is likely to act as a regulatory mechanism in fish stocks that are recovering from overfishing. In general, density dependence in fish stocks is assumed to only occur in reproduction and early life stages and is therefore usually modelled as a stock-recruitment relationship. Recent research shows that density dependence can also reduce individual growth in body size later in life. In this study, we show how optimal fishing effort changes with the strength of density dependence in individual growth for four stocks of North Sea flatfish species. Using size-structured population models we show that density dependence arises due to a mechanistic link between the resource availability and life history processes at the individual level. We furthermore show that the stock response to harvesting is either driven by changes in individual reproduction when density dependence in individual growth is weak or by changes in individual growth rate when individual growth is strongly affected by density dependence. These two types or regimes are separated by a sudden shift in dynamics. It is therefore of great importance to account for density dependence in growth when managing fish stocks.     

阿根廷专属经济区内鱿钓渔场时空分布年间差异比较

阿根廷滑柔鱼(Illex argentinus)是西南大西洋重要的经济性头足类,其中分布在阿根廷专属经济区的渔场是极为重要的作业海区,掌握其渔场时空分布有助于合理利用该资源。根据2008～2011年中国鱿钓船在阿根廷专属经济区内的生产统计资料,利用空间距离分析和聚类分析,对渔场时空分布及其年间差异进行了研究。结果表明,阿根廷专属经济区内2008年的产量明显高于其它三年,2008年渔场主要分布于46°S以南,与其它三年也有所差异。产量重心在各年的2月份差异最小,3月份显示出较大的差异。计算欧式距离表明,2008年和2010年产量重心空间距离最小,2010年和2011年空间距离最大。聚类分析表明,2008年与2010年归为一类,2009年和2011年为一类。对不同月份进行聚类分析发现,不同年份2月均在一类中,空间差异较小,其它月份并没有呈现出明显的规律性变化,同一年相邻月份渔场变化不明显。研究认为,阿根廷滑柔鱼年间渔场分布变化很大,今后应该结合各项生物学指标和海洋环境因子进行全面的分析。     

限制饲养对肉鸭生产性能和屠体品质的影响

选用1日龄樱桃谷肉鸭200只，随机分为两组，1个试验组，1个对照组，每组2个重复，每个重复50只。对照组1～6周自由采食，试验组1～3周自由采食，4～6周采用限制饲养（限量）。试验结果表明：6周龄时，试验组的饲料转化率比对照组提高了12．9％，差异显著（P＜0．05），但日增重降低了9．13％，差异不显著（P＞0．05）；腹脂率降低34．2％，差异极显著（P＜0．01）；皮脂率降低15．1％，差异显著（P＜0．05）；瘦肉率提高了11．9％，差异不显著（P＞0．05）。     

2011年西南大西洋拖网渔获物阿根廷滑柔鱼生物学分析

根据2011年1月～4月双拖网船在西南大两洋作业时采集的901尾阿根廷滑柔鱼（lllex argentinus）样本,对其渔获群体组成、摄食等级、胴长-体质量关系以及性腺发育等进行了分析。结果表明,样本个体大小随采样时间的推移有明显增大趋势;小胴长组阿根廷滑柔鱼的摄食能力较大胴长组弱,摄食等级的高低与其繁殖高峰期有关。阿根廷滑柔鱼雌、雄初次性成熟胴长分别为191．6mm和182．6mm,性腺成熟度为Ⅴ期个体的平均胴长小于处于Ⅲ、Ⅳ期个体的平均胴长。综合分析推测,该研究采集的901尾样本为南部巴塔哥尼亚群体和夏季产卵群体的混合样本,在拖网作业后期,渔场补充了部分大个体的夏季群体。     

广东大鹏湾虾拖网网囊网目选择性研究

虾拖网渔业是南海海域重要的作业方式之一,但尚未有关该渔业网目尺寸选择性的报道。为评价虾拖网渔具的渔获性能、合理利用虾类资源,在广东大鹏湾进行了网目选择性试验。试验采用双支架虾拖网作为试验网具,并使用套网法估算了网目内径为35、40和45 mm的网囊对主捕虾类的选择性。结果显示,虾类渔获中刀额新对虾、须赤虾、周氏新对虾和日本囊对虾渔获数量较多,比较以往资料,刀额新对虾和周氏新对虾优势体长、平均体长均有所下降,其它2种虾类平均体长未见明显变化;选择性分析结果显示,主捕虾类的L50随网目尺寸线性增大。根据试验结果并结合历史资料,笔者认为现阶段35 mm的网囊网目尺寸对于保护上述4种虾类资源是比较合适的。