魁蚶工厂化育苗技术

当魁蚶栖息水温达14～20℃时采捕亲贝,使用浮筏式网箱进行暂养。催产时及时挑出雄贝以防止精液密度过大,提高受精率和孵化率。人工催产除采用阴干、流水、升温法,使用漂白液处理海水法也可获得理想的效果。幼虫培育密度以6～10个/ml 为宜。投喂叉鞭金藻加小球藻混合饵料效果最佳。当出现雏形足的幼虫占10%～20%,且壳长大于240μm 的个体占30%以上时投放附着基,附着基以红棕绳最好。     

养殖皱纹盘鲍人工育苗LED光质及光照时期优选

光照是影响水生生物生长发育和存活的重要环境因子之一。该文研究了不同光质(红光、橙光、白光、蓝光、绿光和黑暗环境)和光照起始阶段(分别从受精卵,担轮幼虫,眼点幼虫)对皱纹盘鲍幼虫生长发育和存活的影响。试验结果表明:在蓝、绿光以及黑暗环境下,幼虫的孵化率都超过80%,与红、橙、白光组相比差异显著(P0.05)。红、橙、白光下,幼虫的畸形率则均较高,且与其他光质组相比差异显著(P0.05)。而在红光下,幼虫的畸形率显著高于其他处理组(P0.05),超过10%。蓝光下,从担轮幼虫阶段起始光照,幼虫的变态率显著高于其他光质组。红、橙光和黑暗环境下,不同光照起始阶段幼虫的变态率均较低且没有显著性差异(P0.05)。从受精卵阶段起始光照,蓝光下幼虫的变态率显著高于其他光质组(P0.05),绿光和白光下幼虫的变态率也较高且二者间并没有显著性的差异(P0.05)。从受精卵阶段起始光照,蓝、绿光和黑暗环境下担轮幼虫的规格显著大于白、红光组(P0.05),且3种光质间并没有显著性的差异(P0.05)。蓝、绿光下,从担轮幼虫和面盘幼虫阶段起始光照,幼虫形成次生壳和变态时的规格显著大于从受精卵阶段起始光照组(P0.05),但从眼点幼虫阶段起始光照组,幼虫所需的变态时间显著长于从受精卵和担轮幼虫阶段起始光照组(P0.05)。因此,在皱纹盘鲍的幼虫培育过程中,选择蓝、绿光并且从担轮幼虫期起始光照对提高苗种孵化效率、增加单位水体产量和促进鲍育苗技术发展具有重要意义。     

Fluctuations of diptera larvae in soil from a spruce forest in relation to climatic factors

Summary Diptera larvae were extracted by the wash and flotation method according to Healey and Russell-Smith (1970) as modified by Altmüller (1979). The larvae had been kept in alcohol for at least 2 months. After this time their specific gravity changed, and an additional flotation with MgSO₄-water solution of SG = 1.26 g/cm³ was very effective. This new method is described. The working procedure can be reduced to about 50%–70% of the time Altmüller (1979) and Hövemeyer (1984) needed. Many tests have shown that some small sciarid larvae settle out with the needle and humus particles in solution of SG = 1.26 and cannot be found, so that it is necessary to apply a correction factor. Samples taken each August from 1979 to 1984 were extracted and floated off by the methods described. Larvae from seven families of Diptera nematocera and from six families of Diptera brachycera were found. Numbers of sciarid larvae varied between 2500 (1979) and 100/m² (1981), of the cecidomyid larvae between 6700 (1983) and 400/m² (1980) and of the brachyceran larvae between 650 (1979) and 50/m² (1984). The correlation coefficient (= r) of larval population size with temperature and precipitation, respectively, was calculated and hence the coefficient of determination as a percentage (r ² x 100), which represents the proportion of the fluctuations in population size that is accounted for by weather factors. All families were influenced negatively by the temperature and positively by the precipitation in August, i.e., the higher the precipitation and the lower the temperature in August the higher the larval abundance in August. The development of the larvae begins in the previous year, and the influence of monthly climatic factors during the whole period of development was tested. It was shown that: Precipitation is correlated with the abundance of (1) sciarid larvae in June and August of the previous year (positively); (2) brachyceran larvae in June (August) of the previous year and in (February), March, April and August of the same year (positively); and (3) cecidomyid larvae in July of the same year (negatively). Temperature is correlated with the abundance of (1) sciarid larvae in August of the previous year (negatively); (2) brachyceran larvae in August of the previous year (negatively); and (3) cecidomyid larvae in September of the previous year, in January and July of the same year (positively). Monthly data for precipitation and temperature, taken together, showed maximum positive correlations with abundance as follows: (1) for sciarid larvae, with data for August of the previous year; (2) for brachyceran larvae, with data for August of the previous year; (3) for cecidomyid larvae, with data for July of the same year.     

Larval and adult species composition, phenology and life cycles of carabid beetles (Coleoptera: Carabidae) in an organic potato field

Carabid larvae and adults were collected by pitfall trapping and soil sampling for a period of 1 year from an organic potato field in western Austria. The main results and conclusions were the following. (i) Larval catches enriched the total species spectrum (n = 49) by 6 %. Recording of pre-adult stages seems to be necessary for a complete registration of a beetle coenosis. (ii) Twenty species were caught in adult as well as in larval stages, representing apparently the autochthonous Carabidae of the investigated field. (iii) The use of soil sampling enriched the larval ground beetle spectrum and provided additional data on the life cycle of certain species. Therefore additional methods to pitfall trapping are stated to be important. (iv) Epigaeic activity of winter larvae surpassed that of adults during late autumn, winter and early spring, whereas summer larvae lived mainly hemiedaphicly. (v) Third instar larvae showed the highest pitfall catches in most species, which was probably caused by their higher epigaeic activity and greater activity radius. (vi) Life cycles of Nebria brevicollis, Loricera pilicornis, Calathus fuscipes, Amara aulica, Harpalus rufipes, Bembidion lampros and B. properans are presented and discussed. Data of larvae support the concept of species which reproduce a second time or show two breeding cohorts throughout the year. (vii) Carabid larvae may possess interesting predation value in the regulation of certain pests due to a phenology and habitat that differ from that of adult beetles.

Résumé

Dans un champ de pommes de terre cultivé biologiquement dans l'ouest de l'Autriche, les larves et adultes de différentes espèces de carabes ont été récoltés par piégeage Barber et échantillonnage de sol pendant 1 an. Les principaux résultats et conclusions sont les suivantes. (i) La capture de larves a enrichi tout le spectre de l'espèce (n = 49) de 6 %. L'enregistrement des étapes pré-adultes semble donc être nécessaire pour obtenir une image complète d'un peuplement de coléoptères. (ii) Les vingt espèces de larves et d'adultes récoltées semblent bien représenter la composition de carabes autochtones de la zone étudiée. (iii) L'échantillonnage du sol a enrichi le spectre larvaire carabiques et a fourni des données supplémentaires sur le cycle de vie de certaines espèces. Des méthodes complémentaires au piégeage Barber semblent donc être importantes. (iv) Tandis que les larves en été sont principalement semi-édaphiques, l'activité épigée des larves en hiver a surpassé celle des adultes pendant l'automne, l'hiver et le début de printemps. (v) En raison probablement de leur activité épigée plus élevée et de leur rayon d'action plus grand, c'est dans les pièges Barber que le plus grand nombre de larves de troisième stade de la plupart des espèces a été observé. (vi) Les cycles de développement de Nebria brevicollis, Loricera pilicornis, Calathus fuscipes, Amara aulica, Harpalus rufipes, Bembidion lampros et B. properans sont présentés et discutés. Les données larvaires confirment l'idée que ces espèces se reproduisent deux fois par an ou que deux cohortes successives peuvent se reproduire chaque année. (vii) En raison d'une phénologie et d'un habitat qui diffèrent de celui des coléoptères adultes, les larves de carabes pourraient jouer un rôle important dans la régulation de certains parasites.     

Diet overlap between young-of-the-year perch, Perca fluviatilis L., and burbot, Lota lota (L.), during early life-history stages

Abstract –  The diet overlap between young-of-the-year (YOY) perch and burbot in the pelagic zone of Lake Constance during spring and summer was investigated in relation to gape size limitation. Because perch were larger and grew faster than burbot during their early life history, perch overcame gape size limitation for various zooplankton taxa earlier than burbot. The interspecific diet overlap between perch and burbot decreased continuously until June, but increased slightly, when burbot became able to feed on large daphnids by the beginning of July. All zooplankton taxa could be found within perch stomachs by the middle of June, when perch overcame gape size limitation for large cladocerans. However, there was an increasing tendency for individual diet specialisation of perch, as the similarity between individual perch stomach contents decreased. In contrast, the similarity between individual burbot stomach contents remained at almost 50% until the end of August, indicating that all burbot rely on cyclopoid copepods during their entire pelagic life-history stage. Because by July YOY perch are more abundant by one order of magnitude in the pelagic zone than burbot, YOY perch may be more affected by intraspecific competition than by interspecific competition with burbot. Burbot, on the other hand, may evade strong competition with YOY perch by performing diel vertical migrations, thus being restricted to feed on migrating zooplankton prey.     

Testicular development and serum profiles of steroid hormone levels in captive male Pacific herring Clupea pallasii during their first maturational cycle

The present study investigates the relationship between testicular development and serum steroid hormone levels in captive Pacific herring Clupea pallasii during the first reproductive cycle. The maturity of the testis was divided into five periods based on histological observation. These are early spermatogenic stage (April to July), mid-spermatogenic stage (August to November), late spermatogenic stage (December to March), functional maturation stage (early April) and spent stage (late April). The pattern of seasonal change in gonadosomatic index (GSI) clearly reflected testicular maturity. 11-Ketotestosterone (11-KT) levels increased from October to a peak level (6.58 ± 1.87 ng/mL) in January, and were maintained at this level until March. In contrast, testosterone levels were consistently low, less than 1 ng/mL, at all times. These results suggest that 11-KT is the predominant androgen that controls spermatogenesis in this species. 17,20β-Dihydroxy-4-pregnen-3-one (DHP) showed a single sharp peak (3.38 ± 0.35 ng/mL) in early April of the second year, suggesting that milt production is induced by DHP as in some other teleost species.     

三种饲料单独及组合投喂对多鳞白甲鱼仔鱼生长及存活率的影响

本研究旨在探讨商品饲料、黑水虻粉、裂殖壶藻粉单独及其组合投喂对多鳞白甲鱼仔鱼生长及存活率的影响。将1350尾出膜后5 d的健康多鳞白甲鱼仔鱼随机分为3组,每组3个重复,进行两个阶段为期25 d的饲养试验,前10 d为第一阶段,分别单独饲喂3种饲料,后15 d为第二阶段,向黑水虻粉、裂殖壶藻粉组饲料等比补充商品饲料进行饲喂。结果发现,生长方面,商品饲料组在两个阶段均保持最佳;黑水虻组在第一阶段短期内(前5 d)全长及体质量均最大,第二阶段15 d时体质量出现一定程度负增长(-26.93%),而后恢复增长;裂殖壶藻粉组第一阶段生长表现最差,第二阶段出现一定程度负增长(-10.51%),而后恢复,最终生长情况优于黑水虻粉组。成活率方面,整体成活率商品饲料组最高(85.66±4.51)%,裂殖壶藻粉组次之(72.67±11.57)%,黑水虻粉组最低(60.0±16.17)%;分阶段看,第一阶段裂殖壶藻粉组最高(96.44±2.04)%,其次为商品饲料(91.11±3.08)%,黑水虻粉组最低(85.78±2.77)%,第二阶段商品饲料组最高(85.66±4.51)%,裂殖壶藻粉组次之(75.34±10.24)%,黑水虻粉组最低(69.59±16.79)%。研究表明,本试验条件下,商品饲料作为多鳞白甲鱼仔鱼开口饲料,其生长效果最佳,而裂殖壶藻粉在保持较高存活率方面效果较为明显。今后应进一步研究黑水虻粉及裂殖壶藻粉在饵料中的配比及应用方式。     

旋毛虫肌幼虫总RNA提取方法研究初报

【研究目的】探索高质量的旋毛虫(Trichinella spiralis)肌幼虫总RNA提取方法；【方法】利用Trizol试剂采用三种方法提取旋毛虫肌幼虫总RNA。(1)液氮预冷的研钵中研磨新鲜虫体至样品快融化时，加入适量的Trizol，继续研磨至液状后转移到离心管中；(2)A将新分离的虫体放到-20℃预冷的研钵中，在研磨过程中不断地添加液氮以保持虫体冷冻，之后对冷冻状的样品粉末继续操作；B把液氮冻存的新鲜旋毛虫肌幼虫取出，放到-20℃预冷的研钵中重复A的操作；(3)新鲜虫体放入匀浆器中，加适量Trizol，在冰水混合物中研磨20分钟。虫体破碎后按Trizol说明书继续抽提。最后通过凝胶电泳和紫外吸收光度值检测。【结果】用液氮和Trizol结合的方法，使用新鲜样品提取旋毛虫肌幼虫总RNA，在纯度和得率上都较为理想；【结论】使用新鲜的样品，且液氮与裂解液结合，是获得高质量RNA的可行方法。