萧氏松茎象有虫株率与虫口密度关系的研究

通过对江西萧氏松茎象发生林区118块标准地的调查与分析，得出萧氏松茎象平均虫口密度与有虫株率之间的关系可用指数函数Y=15.6e^0.0313x来描述。     

牙鲆早期发育和变态期间Pitx2基因的表达

Pitx2基因被认为是脊椎动物中调节内脏器官左右不对称的关键转录因子。为进一步探讨牙鲆变态期间的左右不对称是否也受Pitx2的左特异活性调节,采用逆转录聚合酶链式反应(RT-PCR),拟在变态的牙鲆的头部组织中克隆编码Pitx2基因的部分cDNA序列,并通过以18s rRNA为内标的半定量RT-PCR研究其在牙鲆早期发育和变态期间的表达情况。克隆和测序的结果表明Pitx2在牙鲆早期发育和变态期间也存在基因表达;而半定量的结果表明它的左特异性功能很可能在变态的早期阶段发挥作用。但是,牙鲆变态期间的右眼移动是否受Pitx2的左特异活性调控,以及变态期间的左右不对称和内脏器官的左右不对称是否拥有相同的分子机制,仍需进一步研究。     

海湾扇贝“中科红”品种与普通养殖群体不同温度下早期性状的比较

采用自交、杂交和混交等不同的交配方式分别获得海湾扇贝“中科红”品种和普通养殖群体（对照组）的受精卵和幼虫,在20 ℃、23 ℃和26 ℃三个温度条件下培养,比较了两个群体在不同温度下的孵化率、10日龄幼虫存活率、1日龄和10日龄幼虫壳长。实验结果表明：“中科红”海湾扇贝自交系、杂交系和混交系的孵化率均大于对照组。自交系10日龄幼虫存活率显著高于对照组（P＜0.05）,而杂交系和混交系的10日龄幼虫存活率小于对照组,但差异不显著（P＞0.05）。“中科红”海湾扇贝自交系（P＜0.05）和混交系幼虫的1日龄壳长大于对照组,杂交系的显著小于对照组（P＜0.05）。幼虫生长10日后,“中科红”海湾扇贝自交系、杂交系（P＜0.05）和混交系幼虫壳长均比对照组大,表现了较强的生长优势。温度对4个性状均有显著影响（P＜0.05）。“中科红”海湾扇贝对低温（20 ℃）和高温（26 ℃）的耐受性均高于对照组。     

虎斑乌贼喷墨卵与正常卵的比较

为了探明虎斑乌贼喷墨卵对孵化及胚胎发育的影响,采用单因子实验研究了喷墨卵与正常卵的孵化率、培育周期、孵化周期、初孵幼体体质量,并比较了剥膜喷墨卵、剥膜正常卵、喷墨卵、正常卵4种类型卵的幼体生长和存活率。结果显示,虎斑乌贼喷墨卵和正常卵的孵化率无显著差异,喷墨卵的孵化率为90.1%±1.5%,正常卵的孵化率为87.9%±0.7%;两种卵的初孵幼体体质量也无显著差异,喷墨卵的初孵幼体体质量为(0.18±0.01)g,正常卵的初孵幼体体质量为(0.17±0.01)g;两种卵的培育周期、孵化周期均无显著差异,喷墨卵的培育周期为(34.67±0.89)d,孵化周期为(14.33±0.44)d,而正常卵的培育周期为(35.33±0.44)d,孵化周期为(14.67±0.67)d。而剥膜喷墨卵、剥膜正常卵、喷墨卵、正常卵4种类型卵的幼体存活率差异显著,剥膜喷墨卵和剥膜正常卵的存活率明显小于喷墨卵和正常卵,而剥膜喷墨卵和剥膜正常卵之间、喷墨卵和正常卵之间的存活率无显著差异;4种类型的幼体日均增长量和增重量差异显著,剥膜喷墨卵和剥膜正常卵的幼体日均增长量和增重量明显小于喷墨卵和正常卵,而剥膜喷墨卵和剥膜正常卵之间、喷墨卵和正常卵之间的幼体日均增长量和增重量无显著差异。     

Importance of dietary arachidonic acid for the growth,survival and stress resistance of larval European sea bass (Dicentrarchus labrax) fed high dietary docosahexaenoic and eicosapentaenoic acids

Together with docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), arachidonic acid (ARA) is being considered to be an essential fatty acid in marine fish larval diets. The objective of the present study was to determine the importance of dietary ARA levels for larval European sea bass performance, when EPA and DHA are also present in the diet. Eighteen‐day‐old larvae were fed, for 14 days, gelatine‐based microdiets containing the following ARA levels: 0.3%, 0.6% or 1.2%. Elevation of dietary ARA up to 1.2% showed a positive correlation with larval survival and a significant improvement in the specific growth rates, body weight and total length. Arachidonic acid was efficiently incorporated into larval lipids, even at a higher proportion than that in the diets. Increased accumulation of ARA did not affect the incorporation of DHA or EPA from the diet into larval total lipids. A significant positive correlation was found between dietary ARA levels and survival after handling stress, indicating the importance of this fatty acid in sea bass larvae response to acute stressors. The results show the importance of ARA for sea bass larvae, but higher dietary levels should be tested to determine whether there is a negative effect of ARA in sea bass as reported for other species.     

雅砻江硬刺松潘裸鲤的胚胎及仔鱼发育研究

研究硬刺松潘裸鲤(Gymnocypris potanini firmispinatus)早期生活史阶段的发育规律,为松潘裸鲤的亚种分化研究、规模化人工繁殖和苗种培育提供理论依据。松潘裸鲤亲鱼采自雅砻江支流安宁河流域。雌鱼6~13龄,全长12.1~24.2cm,体重16.1~115.8g;雄鱼3~9龄,全长8.2~14.5cm,体重5.2~23.8g。结果显示,硬刺松潘裸鲤受精卵呈圆形,黄色,卵径(2.82±0.10)mm;水温(16±1)℃下,硬刺松潘裸鲤的胚胎发育历时183h45min,胚胎发育过程分为受精卵、胚盘形成、卵裂、囊胚、原肠、神经胚、器官分化和出膜共8个阶段、31个时期;出膜仔鱼全长(7.82±0.19)mm;出膜10d后,仔鱼的鳃、口、胸鳍、尾鳍、鳔、肠道等功能器官先后形成;出膜13d后卵黄囊消失,全长(14.33±0.51)mm;出膜40d后各鳍基本长成,体型和体色接近成鱼,进入幼鱼阶段。硬刺松潘裸鲤为地区重要的小型经济鱼类,主要分布在雅砻江中游各大干支流中,在形态和生态上形成一系列的适应性,早期发育过程与其栖息的环境同样具有一定的适应性。     

Distribution of jack mackerel (Trachurus japonicus) larvae and juveniles in the East China Sea, with special reference to the larval transport by the Kuroshio Current

Horizontal distribution patterns of jack mackerel (Trachurus japonicus) larvae and juveniles were investigated in the East China Sea between 4 February and 30 April 2001. A total of 1549 larvae and juveniles were collected by bongo and neuston nets at 357 stations. The larvae were concentrated in the frontal area between the Kuroshio Current and shelf waters in the upstream region of the Kuroshio. The abundance of small larvae (<3 mm notochord length) was highest in the southern East China Sea (SECS) south of 28°N, suggesting that the principal spawning ground is formed in the SECS from late winter to spring. Jack mackerel also spawned in the northern and central East China Sea (NECS and CECS, respectively), as some small larvae were also collected in these areas. In the SECS, the abundance of small larvae was highest in February and gradually decreased from March to April. The habitat temperature of small larvae in the SECS and CECS (20–26°C) was higher than that in the NECS (15–21°C), suggesting higher growth rates in the SECS and CECS than in the NECS. The juveniles (10‐ to 30‐mm standard length) became abundant in the NECS off the west coast of Kyushu Island and CECS in April and were collected in association with scyphozoans typical of the Kuroshio waters. However, juveniles were rarely collected in the SECS, where the small larvae were concentrated. Considering the current systems in the study area, a large number of the eggs and larvae spawned and hatched in the SECS would be transported northeastward by the Kuroshio and its branches into the jack mackerels’ nursery grounds, such as the shallow waters off the west coast of Kyushu and the Pacific coast of southern Japan.     

金属离子Ni2+和Co2+对卤虫孵化率和变态率的影响

在去除重金属离子的天然海水中添加不同浓度的Ni^2 和Co^2 进行养殖实验，研究了Ni^2 和Co^2 对盐卤虫（Artemia saline)孵化率及变态率的影响。在试验过程中保持温度（27℃）、盐度（30‰）以及pH(=8)恒定。结果表明：当海水中Ni^2 和Co^2 浓度分别为40μg/L和30μg/L时对旧金山湾卤虫的孵化最为有利，当Ni^2 浓度为40μg/L,Co^2 浓度为40μg/L-50μg/L时对其发育变态最为有利。从而得出结论：当海水中Ni^2 浓度在40μg/L范围左右时可促进卤虫的孵化及变态发育，当海水中Co^2 浓度为30μg/L-50μg/L范围内时可促进卤虫的生长发育。     

Variation in the distribution of ocean shrimp (Pandalus jordani) recruits: links with coastal upwelling and climate change

In this analysis, an atypical northward shift in the distribution of age‐1 ocean shrimp (Pandalus jordani) recruits off Oregon in 2000 and 2002–2004 was linked to anomolously strong coastal upwelling winds off southern Oregon (42°N latitude) in April–July of the year of larval release (t?1). This is the first clear evidence that strong upwelling winds can depress local recruitment of ocean shrimp. Regression analysis confirmed a long‐term negative correlation between log_e of ocean shrimp recruitment and April sea level height (SLH) at Crescent City, California, in the year of larval release, for both northern and southern Oregon waters. The regional pattern of ocean shrimp catches and seasonal upwelling winds showed that, although the timing of the spring transition as reflected in April SLH drives ocean shrimp recruitment success off Oregon generally, the strength and consistency of spring upwelling limits the distribution of large concentrations of ocean shrimp at the southern end of the northern California/Oregon/Washington area. A northward shift in 1999 and 2001–03 in the northern edge of this ‘zone of maximum upwelling’ is the likely cause of the weak southern Oregon recruitment and resulting atypical distribution of ocean shrimp observed off Oregon in 2000 and 2002–04, with a return to a more typical catch distribution as spring upwelling moderated in subsequent years. It is noted that a northward shift in the conditions that produce strong and steady spring upwelling winds is consistent with many predictions of global climate models under conditions of global warming.