胶州湾移植底播菲律宾蛤仔面盘幼虫生物学特性研究

2006年5～9月,通过浮游拖网调查对胶州湾移植底播菲律宾蛤仔面盘幼虫(D形幼虫)生物学特性进行研究,结果表明:移植底播菲律宾蛤仔面盘幼虫壳长、壳高呈线性相关,与其它蛤仔种群面盘幼虫差异显著。     

密度及饵料对鲍苗生长与成活率的影响

研究了后期面盘幼虫不同采苗密度、不同底栖硅藻与稚鲍不同培育密度,对鲍苗的生长与成活率的影响。认为最佳采苗密度应为2万个／m2后期面盘幼虫;当地底栖硅藻混合种的饵料效果优于纯种,剥离后稚鲍的培育密度不直超过4000粒／m2。在640m2水面中有出壳长1．2～1．5cm鲍苗201．6万粒,平均出苗量3150粒／m2。专家鉴定认为,本课题在皱纹盘鲍不同育苗密度、不同饵料对育苗效果的研究方面居国内领先水平。     

盐度对大连湾牡蛎胚胎发育及幼虫生长的影响

本文阐述了大连湾牡蛎胚胎发育速度和盐度变化对其胚胎及幼虫的影响。结果表明:在水温 21.2℃、盐度 31.26‰条件下,受精卵经 19小时 30分钟发育至 D形幼虫。其胚胎发育的有效盐度范围为17—39‰,最适盐度范围为22—34‰。在盐度22—36‰条件下,胚胎发育速度较快,均不超过20小时,超出此盐度范围,则孵化时间延长。面盘幼虫在盐度25.21—34.25‰间生长较快,平均口增长速度为 8.54—9.38 微米,且存活率均在 50％以上;逾此则生长速度和存活率均有不同程度的降低。     

黄口荔枝螺早期发育的初步研究

对黄口荔枝螺Thais luteostoma早期发育进行了研究,详细记录了其早期发育过程中的发育时间与特征,并对各阶段进行显微摄像。结果表明：黄口荔枝螺卵囊高度平均为7．33mm,卵粒数量平均为165粒;黄口荔枝螺的早期发育属间接发生型,受精卵呈椭圆形,卵裂为盘状卵裂;在卵囊内,胚胎发育包括卵裂期、囊胚期、原肠胚、膜内担轮幼虫、膜内面盘幼虫;幼虫发育包括面盘幼虫、后期面盘幼虫和匍匐幼虫。从受精卵到面盘幼虫均见营养卵的存在。     

石磺繁殖生物学的实验研究

用实验室小型试验、贝类育苗场生产性试验和自然群体实地观察的方法，结合养殖池塘内石磺（Onchidium sp.）繁殖习性跟踪观察，2年内研究了沪浙地区石磺的繁殖季节，繁殖方式，繁殖力，受精卵的发育孵化，水温和盐度对胚胎发育的影响，胚胎停止发育现象，幼虫发育及变态前形态变化，对石磺繁殖生物学作了比较系统的实验研究。结果显示石磺雌雄同体，雄性先熟，异体交配，体长5 cm体重10 g以上的个体为繁殖的主要群体，其生物学最小型为体长3.1 cm和体重3.5 g；交配期多在气温22 ℃以上的5月中下旬至9月下旬，6～8月为繁殖盛期。产卵前经过5～10 h的求爱和1～5 h的交配过程，交配后15 d左右产出受精卵，多在大潮日至小潮日期间3～5 d内的晚间产卵；繁殖期具有6个明显的产卵高峰。卵群表面积15～30 cm²，每平方厘米卵群含卵子2 650±300个，每个卵群含卵子4.4～8.0万粒。水里与潮湿环境中卵群孵化率没有明显差异；26～35 ℃的水温下，卵群孵化时间10～14 d，水温23 ℃以下石磺胚胎出现停止发育的现象。适合卵群孵化的海水盐度为6～20，孵化出膜2～3 d后的面盘幼虫开始摄食单胞藻。自由生活面盘幼虫经23 d培育后出现明显的革质膜；变态后的幼体可能存在不断蜕去革质膜的过程，面盘幼虫的变态过程和变态条件仍有待研究。     

培育密度对长牡蛎面盘幼虫生长影响的对比试验

长牡蛎育苗期间经常出现面盘幼虫生长参差不齐现象,影响单位水体出苗量。笔者在正常培养密度范围内6～12个 ml作对比试验:低密度6～8个 ml培养的幼虫生长速度快,个体差异小;重视亲贝促熟,加强优质新鲜饵料的供给,有良好的水环境,能够减少幼虫差异显著的现象。     

Eradication of colonizing populations of zebra mussels (Dreissena polymorpha) by early detection and SCUBA removal: Lake George,NY

• 1. Since their introduction to North America, zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis) have rapidly colonized North American fresh waters. Strategies for limiting the economic and ecological impacts of zebra mussels exist, but there are few examples where once zebra mussels have invaded a natural body of water they have been removed or managed without the use of ecologically destructive methods. The first successful attempt to eradicate a colonizing population of zebra mussels using SCUBA is reported here. Studies were conducted in Lake George, NY.
• 2. Since zebra mussel larvae had been detected prior to the discovery of adults in Lake George, a comprehensive management programme for zebra mussels was in place when mussels were found in 1999, at a single location in the southern part of the Lake (Lake George Village site). Efforts were quickly launched to remove as many mussels as possible by SCUBA with the intent of minimizing the risk of the population reproducing and establishing a permanent presence in the Lake.
• 3. Population size at the discovery site was initially estimated at fewer than 30000 animals. Between 1999 and 2007 more than 21000 animals were removed from the site, over 90% of them shortly after the colony was discovered. Continued monitoring of the site for larvae, recruitment, and growth suggests that the animals have not successfully reproduced since the project began. Since detection at the Lake George Village site, six separate colonizing populations at other locations in the lake were found and similar removal efforts appear to be having comparable success.
• 4. This study demonstrates that the combination of early detection, suboptimal habitat, proactive establishment of a rapid response and management plan, and cooperation of a comprehensive network of stakeholders can prevent a successful zebra mussel invasion.Copyright © 2009 John Wiley & Sons, Ltd.

     

脉红螺早期发育的观察

在实验室条件下对脉红螺Rapana venosa早期个体发生及其发育过程进行了研究.结果表明：脉红螺的发育属间接发生型,其胚胎发育包括卵裂、囊胚、原肠胚、膜内担轮幼虫和膜内面盘幼虫;幼虫发育包括面盘幼虫、后期面盘幼虫和匍匐幼虫,匍匐幼虫经变态后发育为稚螺;在水温为21 ～22℃的条件下,受精卵需18 ～20 d发育至膜内面盘幼虫,经20～ 26 d后,面盘幼虫逐渐破膜而出;脉红螺面盘幼虫具有1对眼点和1对平衡囊,面盘呈双叶状,后期面盘幼虫的面盘中部开始凹陷,并逐步加深成4叶,呈蝶状,足发达,幼虫既能浮游又能爬行,随着进一步的生长发育,逐渐转入匍匐生活,成为稚螺.     

瘤背石磺的胚胎和幼虫发育

在水温27～29℃、气温27～31℃和海水盐度为16的环境条件下人工孵化瘤背石磺的卵块,根据早期发育的形态变化将其划分为胚胎发育(包括卵裂期、囊胚期、原肠期、卵内担轮幼虫、卵内面盘幼虫)和幼虫发育(包括开口期、大面盘幼虫、附着期、匍匐幼虫)两个阶段。受精卵发育至卵内担轮幼虫需要51h,胚胎发育89h后变态为卵内面盘幼虫,第7天面盘幼虫孵化出卵,直径增大1倍;第23天幼虫变态为匍匐幼虫,虫体直径为受精卵的4倍。分析认为,瘤背石磺的胚胎发育具备典型的不等全裂、螺旋卵裂特征,幼虫为典型的腹足纲面盘幼虫形态;温度对胚胎发育时间影响显著而充气可以加速幼虫孵化出卵;面盘幼虫需要有适宜的潮间带环境和饵料(如底栖硅藻)才可以正常附着变态。     

Effects of Cu,Zn and Cd on larval development and respiratory metabolism of pacific abalone (Haliotis discus hannai)

Trochophore and veliger are vulnerable pelagic larvae and susceptible to environmental toxicants, which are extremely crucial for the population renewal. Cu, Zn and Cd pollution are common elements in metal pollution in coastal areas. Though Pacific abalone is the main economic mollusc in China, its larval response to metals remains unclear. To understand this, the effect of Cu, Zn and Cd toxicity on malformation classification and respiratory metabolism of trochophore and veliger are analysed and measured in this paper. The 48 hr EC₅₀ for abalone trochophore was (18.9 ± 1.0) μg/L for Cu, (65.1 ± 0.3) μg/L for Zn and (1,377.8 ± 68.9) μg/L for Cd respectively. The LC₅₀ of veliger was (45.8 ± 0.9) μg/L for Cu, (50.0 ± 0.9) μg/L for Zn and (1,049.3 ± 37.6) μg/L for Cd respectively. Trochophore died with no shell at 128 μg/L Cu, yet remained alive with multiple broken‐shell bodies at 128 μg/L Zn and failed to form well‐developed shells at 20,480 μg/L Cd. All veliger died with complete shells at the mentioned concentrations. A self‐made device was used to study the effect on respiratory metabolism. The respiratory metabolism level was significantly fluctuating under Cu and Zn exposure and declined under Cd. The results indicated a decreasing order of the metal toxicity to trochophore and veliger as follows: Cu > Zn ? Cd. Cu and Zn were the main causes of shell abnormality, and Cd was less toxic. Moreover, the affected respiratory has a negative impact on further larval development.