耗氧率及溶氧胁迫对长蛸体内酶活力的影响

采用Winkler法测定水中溶氧含量,通过比较对照呼吸室与试验呼吸室水中溶解氧含量之差,测定长蛸(Octopus variabilis Sasaki)耗氧率及窒息点,并在不同程度的溶氧胁迫下测定长蛸体内多种酶的活力变化.结果表明,长蛸耗氧率在一个昼夜内呈现"低-高-低-高"的趋势;耗氧率与水温(10～30 ℃)呈正相关,与pH值(6.40～9.20)呈负相关;随着盐度的升高(14～31),长蛸耗氧率表现为两头高、中间平稳, 曲线呈凹状分布;雌性长蛸耗氧率高于雄性.窒息点随长蛸体重的增加而降低,平均体重为(30.50±6.03)g 的长蛸窒息点为0 4179mg/L;平均体重为 (54.50±4.65) g 的长蛸窒息点为0.3902 mg/L;平均体重为(97 00±11 36) g的长蛸窒息点为0.2738mg/L.随着溶氧胁迫程度的增加,LDH活力呈先升后降趋势,脂肪酶活力下降,SOD、POD、CAT、ACP、AKP和蛋白酶活力均呈"降-升-降"的趋势.     

海州湾日本枪乌贼和短蛸空间结构的季节变化

日本枪乌贼和短蛸是头足类中重要的经济种类,一般为一年生,其空间分布受季节变化的影响较大。由于受调查时间的限制,鲜有在该方面的研究报道。本研究根据2011年春季(5月)、秋季(9月)和冬季(12月)在海州湾及邻近海域进行的渔业资源底拖网调查数据,运用全局空间自相关、热点分析以及变异函数等方法分析了日本枪乌贼和短蛸的空间结构的季节性变化。研究表明:(1)日本枪乌贼和短蛸全局空间自相关性不强,存在局部空间热点,变异函数分析结果与全局空间自相关结果基本一致。(2)日本枪乌贼和短蛸空间自相关的尺度存在季节变化,两个物种均表现为在春季的空间结构性较强,而在秋、冬季的空间结构性较弱,春季的空间自相关性程度高于秋、冬季。(3)在春季,二者均在35.0°~35.5°N、120.0°~121.0°E海域存在一个空间热点,在资源密度最高的季节时其空间分布呈现出随机性特征。物种的空间分布模式可能与环境的季节变化以及其洄游分布和摄食习性相关。本研究有利于深入了解日本枪乌贼和短蛸的生活史特性及其栖息地,可为该资源的合理利用和保护以及后续研究提供理论参考。     

嘉庚蛸精子发生的超微结构

应用透射电镜技术研究嘉庚蛸精子发生过程中各阶段细胞的形态、细胞器及细胞核的动态结构变化。精原细胞呈椭圆形,细胞质少、核大,有线粒体、高尔基体等细胞器;初级精母细胞呈圆形或卵圆形,线粒体多,索条状内质网发达,高尔基体常集中分布,中心粒形成;次级精母细胞呈圆形、椭圆形或不规则形,线粒体嵴发达、基质丰富,高尔基囊泡积累电子致密物,中心粒发出的“9＋2”轴丝结构形成。精细胞分化过程分为6个时期,主要特点为：①核内染色质凝集经颗粒化、纤维化及片层化,最后,形成高电子密度的均质结构;与此相应,核形态由椭圆形、变成长椭圆形、再变成细长柱状,核后端最后向前凹入形成核内沟;精子核的形态建成为染色质的凝集与核周微管加压协同作用的结果。②高尔基囊泡积累电子致密物、融合发育成顶体囊,逐渐延长演变成钻头形的顶体。③线粒体向核后端迁移,形成精子尾部的线粒体鞘。     

真蛸亲体培育、产卵及孵化试验

2005~2007年春、夏期间,在浙江南麂岛开展了真蛸亲体培育、产卵及孵化的试验研究。结果表明:亲蛸培育成活率为77.5%~95.5%,平均产卵率为68.0%~83.3%。不搭配雄体产卵率为65.0%,搭配一定比例的雄体后产卵率达92.5%,最高达100%。不同附卵器附卵效果以方形鲍鱼箱为最好,圆形鲍鱼皮桶次之,扇贝笼最差。在南麂海域暂养在网箱中的真蛸当水温上升到13.5℃以上时就开始有少量产卵,多数开始产卵在16.0℃左右,主要产卵期在4~6月。不同个体真蛸的产卵量变化很大,少者只有22 632粒,多者达170 684粒,平均102 665粒,平均每颗卵粒重量在1.670~2.207 mg之间,大小为长2.8~3.1 mm、宽0.915~0.950 mm。在水温13.5~28.0℃范围内,真蛸卵可以正常孵化,孵化率达60.0%~80.0%,超过28℃时孵化率明显下降。真蛸卵的孵化时间较长,至少需要20 d以上。孵化时间长短与水温关系密切,水温越高,孵化时间越短。孵化期间平均水温16.5℃,整个孵化时间长达47 d。当孵化期间平均水温为21.6℃时,从产卵到稚蛸出膜大致需要25 d左右。此外,还发现亲蛸护卵可以减少疾病,提高孵化率,本文也论述了有关其对疾病防治方面的探索。     

嘉庚蛸对温度、盐度的耐受性试验

2003年4～10月在试验条件下研究了嘉庚蛸成体对温度、盐度等环境因子的耐受能力。利用温水和冰水调节水温，在温控加热器和生物冰袋的协助下完成温度耐受性试验；通过淡水和海水晶调节试验过程中所需的盐度变化。试验结果表明：嘉庚蛸的适宜温度范围为12．0℃～31．0℃，临界上限水温为35．2℃，临界下限水温为0．5℃；耐受盐度的范围比较广泛，为4．8～48．5，适宜养殖的盐度为18．4～33．1。较高的耐受性范围可以保证嘉庚蛸更好地适应其生存的环境，不至于由于环境因子的激变造成嘉庚蛸的大规模死亡。因此，人工养殖和育苗过程中，保持环境因子的稳定是获得高孵化率的先决条件。     

短蛸幼体同类相残行为的观察

在不同条件下,对短蛸幼体（平均体重0.03～0.66 g）进行同类相残研究。结果表明：①相同规格的小规格幼体较大规格幼体日相残率高,相残最严重的时期是在平均体重0.03～0.08 g阶段,当平均体重0.23 g以上时,相残行为较弱,当平均体重0.66 g时,幼体基本不再相残。②放养密度高低、饵料是否适口和有无遮蔽物对日相残率影响显著。③温度对短蛸幼体的相残行为有影响。④幼体间个体大小存在差异,尤其是小规格幼体间出现个体大小差异时,小个体更易受到攻击,相残行为严重。基于以上研究结果,饵料不适口和无遮蔽物是导致短蛸幼体发生同类相残的主要原因,高密度养殖、养殖温度高和个体大小的差异会诱发和促进同类相残的发生。     

Digestive dynamics during chyme formation of Octopus maya (Mollusca,Cephalopoda)

In the present study, digestive dynamics, measured through the changes in the in situ pH along the digestive tract, was evaluated along with the glycogen concentration in the digestive gland (DG) and the proteolytic enzyme activity of the gastric juice (GJ) (both acid and alkaline proteases) to obtain useful information that will allow for the understanding of the DG's function and the role that it plays as an extracellular digestive enzyme source and for energy storage, providing new information on the digestive physiology of Octopus maya. The results showed that pH along the digestive tract changed according to the postprandial time following the food transit. At the beginning, the pH on crop (St) was 5, changing to 6 when the food arrived. Similar changes were observed on the caecum (Ce) and DG. Glycogen from DG is used as a source of energy during digestion and recovered 8 h after feeding. Maximum activities of digestive gland GJ enzymes were observed 6 h after feeding, indicating that chyme enzymes are still active when they arrive at the DG's lumen. The presence of food in the digestive tract modifies the pH, which, in combination with GJ, favours the activity of the released enzymes of O. maya.     

长蛸ISSR-PCR优化反应体系的建立及优化研究

以长蛸DNA为模板,利用单因子试验分别对影响长蛸ISSR-PCR反应的DNA浓度、Taq DNA聚合酶、Mg2＋、dNTPs和引物的浓度进行了优化,并通过梯度PCR确定最适退火温度,最终确定长蛸最佳反应体系和PCR扩增程序为：25μL体系,其中包括Taq DNA聚合酶1.5 U,Mg2＋2 mmol/L,dNTPs 0.15 mmol/L,引物0.4μmol/L,DNA模板量约50 ng确立退火温度为52℃。利用所建立的ISSR-PCR反应体系,通过对24份野生长蛸样本的检验,获得了清晰、重复性好、多态性高的条带,研究结果对于把ISSR标记技术引入研究长蛸不同地理群体遗传多样性和遗传结构具有重要意义。     

The importance of retention processes in upwelling areas for recruitment of Octopus vulgaris: the example of the Arguin Bank (Mauritania)

The relationship between recruitment of octopus ( Octopus vulgaris ) populations and environmental conditions off the Arguin Bank (Mauritania) in the main nursery ground was investigated between 1990 and 1996. Three environmental indices (coastal upwelling intensity, coastal retention and wind-induced turbulence indices) are derived from satellite infrared imagery (METEOSAT) and from the COADS (Comprehensive Ocean–Atmosphere Data Set) data to quantify the coastal retention process and productivity, both believed to be important factors for recruitment success. The octopus recruitment index as well as environmental indices fluctuate annually and seasonally. Linear regression and generalized additive models (GAM) are used to relate recruitment indices and the environmental conditions prevailing during the early-life planktonic stage, known to be the main critical period of the octopus life cycle. Coastal retention especially appears to be a key factor for recruitment success. Owing to seasonal variations in enrichment and mixing processes, larvae benefit from retention in the spring but are negatively affected by a breakdown in retention in the autumn. Increasing upwelling intensity is beneficial for octopus recruitment, as the Arguin Bank limits the detrimental dispersive effects linked to upwelling.     

Clove oil as an anaesthetic for common octopus (Octopus minor, Sasaki)

We evaluated the anaesthetic effect of clove oil [2‐methoxy‐4‐2‐(2‐propenyl)‐phenol] on the common octopus (Octopus minor), in terms of the time required to become anaesthetized (‘anaesthetic time’) and recovery time. We used a factorial experimental design and administered clove oil at different temperatures (15, 20 and 25°C) and concentrations (50, 100, 150, 200, 250 and 300 mg L⁻¹). We observed a significant (P<0.05) relationship between concentration and temperature, and each variable was effective (P<0.05). Anaesthetic time linearly decreased as the concentration and temperature increased. However, recovery time increased as the concentration increased and temperature decreased. There was no mortality. A concentration of 200 mg L⁻¹ clove oil showed rapid anaesthetic and recovery times in the common octopus, indicating its suitability for this species.