真蛸人工繁殖及受精卵孵化技术研究初报

真蛸为福建省近年来新兴的海水养殖优良种类,具有较高的营养价值、商品价值和产业化养殖前景。本文报道了福建省水产研究所2008年-2011年真蛸人工繁殖及受精卵孵化结果：127头雌亲蛸经强化培育,共有77头产卵,获卵194×10^4粒,孵出143．4×10^4头浮游幼体。雌亲蛸获产率46．2％～86．7％,卵子受精率75．6％-91．8％,受精卵孵化率77．9％～95．0％。在20．0～22．5℃水温条件下,真蛸受精卵经21～36d开始孵出,孵出后4～6d为孵出高峰,每窝卵开始孵出至孵化结束维持10—16d。     

Analysis of bacterial community and bacterial nutritional enzyme activity associated with the digestive tract of wild Chilean octopus (Octopus mimus Gould, 1852)

Information on the bacterial community associated with octopus is very scarce, unlike fish and other molluscs. This study revealed the bacterial community associated with digestive tract of wild Chilean octopus Octopus mimus using a culture‐dependent method and 16S rDNA clone library. Moreover, we analysed the bacterial nutritional enzyme activity of culturable bacteria. A culture‐dependent method showed that the composition of the culturable bacterial community was substantially different between female and male octopus. The predominant species in female octopus were Vibrionaceae and Streptococcaceae, whereas only Vibrionaceae was dominated in male octopus. Bacterial nutritional enzyme activities of culturable bacteria from male octopus were much higher than female octopus. The 16S rDNA clone library analysis showed that the bacterial community of male octopus exhibited a higher diversity than that of female octopus. The genus Mycoplasma was the predominant bacteria in the digestive tract of all octopus samples. The results obtained in this study raise the possibility that each octopus has different food consumption due to different bacterial community and nutritional enzyme activity, although Mycoplasma sp. is one of the predominant bacteria in the digestive tract. Moreover, our results are useful for the future of microbiological investigation associated with the octopus and for probiotics in the octopus aquaculture.     

Trawling for cephalopods off the Portuguese coast—Fleet dynamics and landings composition

Fleet dynamics was addressed for three cephalopod taxa of commercial interest, the squid Loligo vulgaris, the octopuses Octopus vulgaris and Eledone cirrhosa, and the cuttlefish Sepia officinalis, for 48 trawlers of the fish trawling fleet. Landing profiles (LP) were identified based on the species composition of the landings using hierarchical cluster analysis. Four out of a total of 12 different LP were related to cephalopods and other species associated with them.The effects on the landing proportions of a number of variables, year, season and vessel, are analysed for each of the species studied using generalized linear models (GLM). The factor “vessel”, including an ensemble of technical characteristics as well as the abilities of individual skippers, explained most of the model deviance, strongly reinforcing the existence of a fleet component dedicated to catch cephalopods. However, time also explains much of the variation found in the data.Seasonal alternation between landings of octopodidae and cuttlefish was observed within a small group of old trawlers operating mainly off the south coast, following the abundance cycles of these species. For a larger group of more modern trawlers, operating off the western coast, inter-annual shift between octopus and squid was found, together with a well marked seasonal pattern between the catches of cephalopods and horse mackerel.Spatial patterns of activity were identified using vessel monitoring system (VMS) data available for trawlers in Portugal, demonstrating the existence of cephalopod targeting strategies in Portuguese fish trawling activities.     

真蛸人工繁殖初步试验

2005年春、秋两季在福建省大成水产良种繁育试验中心开展了真蛸(Dctopus vulgaris)人工繁殖初步试验.引进本地海区真蛸亲体48头,获得受精卵216万粒,孵化出幼体139万头,在春季成功培育着底幼蛸121头.开口饵料配置试验表明,卤虫无节幼体、轮虫、桡足类可作为真蛸幼体的开口饵料,以卤虫无节幼体为最佳.     

锦香草及其近缘种的亲缘关系ITS序列分析

为厘清锦香草及其近缘种的亲缘关系,为其杂交育种提供数据基础,收集我国锦香草及其近缘种短毛熊巴掌与长柄熊巴掌等样品46份,对供试样品核糖体基因(nrDNA)的内转录间隔区(internal transcribed spacer,ITS)序列进行分析,并构建系统进化树,对其系统发育关系进行研究。结果表明:供试材料的ITS1、ITS2和5.8S的序列长度分别为246、230、160~161 bp;ITS1与ITS2序列存在变异位点426个,信息位点232个;5.8S序列存在202个变异位点,信息位点84个。根据ITS序列构建进化树:供试材料可分为2支,锦香草与短毛熊巴掌在进化树中聚为一支,分支内部互相嵌入;长柄熊巴掌单独聚成一支。以上结果显示,锦香草、短毛熊巴掌亲缘关系较近,它们与长柄熊巴掌亲缘关系较远,该结果支持《Flora of China》将短毛熊巴掌处理为锦香草的异名,长柄熊巴掌为独立种。     

嘉庚蛸雄性生殖系统组织学观察

应用组织切片技术对浙江沿海自然分布的嘉庚蛸雄性生殖系统的结构变化进行了逐月研究,结果发现,雄性生殖系统由单个精巢、输精管、储精囊、前列腺、精荚囊和阴茎等6部分构成。精巢球形,辐射型精巢,精原细胞椭圆或近圆形,直径10～16μm,精子细胞经过椭圆形梭型柳叶型长棒型的变态期,成为鞭毛型精子,精子头部细长等粗棍状,长约26～33μm,尾部长度约为头部的16倍。输精管长约13～16cm,是雄性生殖系统中最细长的管道。储精囊长约5～8cm,可分为储精管和腺体2部分。前列腺与储精囊相接共同开口于精荚囊腔,中空盲管状,4.8～5.6cm。精荚囊分为2部分,一侧为叶脉状规则褶皱突起围成的腺体腔,称之为囊内腺,另一侧突起少,个体大、不规则,树枝状。阴茎短,仅2～3cm,生殖孔开口于胴体左侧外套腔的中部。储精囊、前列腺和精荚囊中均存在着具有分泌功能的上皮构成的腺体腔,它们在精荚成熟装配过程中发挥着不可取代的作用。阴茎中段的阴茎囊呈镜面倒卜型,它不仅是分泌性的腺体腔,而且还是精荚排出过程中的反转场所。     

真蛸孵化过程的初步研究

2007年4月-2008年5月,在嵊山后头湾养殖场进行了真蛸生态育苗试验,研究发现,不同成熟度的真蛸亲体,在卵巢的形状、大小以及卵细胞形态、色泽上有明显差异,并据此可划分为发育间期、成熟期和临产期3个时期。而孵化过程则可分为卵裂初期、＂红珠＂期、＂黒珠＂期及幼蛸出膜期4个阶段。在水温23-28℃、盐度28-31下孵化,约需32 d,孵化过程中受精卵的大小变化不明显,亲体有极强的护卵习性。     

Growth,partial energy balance,mantle and digestive gland lipid composition of Octopus vulgaris (Cuvier, 1797) fed with two artificial diets

Effects of two binders (gelatine and alginate) were tested on growth, survival, partial energy balance and lipid composition of mantle and digestive gland (DG) of Octopus vulgaris. The three diets tested were given as follows: CON, (Loligo gahi) as control, GEL, composed of squid paste (L. gahi) (300 g kg^?1), fish hydrolyse CPSP^® (100 g kg^?1) and fish meal (500 g kg^?1), agglutinated with 100 g kg^?1 of gelatine and ALG, composed of squid paste (L. gahi) (300 g kg^?1), fish hydrolyse CPSP^® (100 g kg^?1) and fish meal (500 g kg^?1), all agglutinated with 100 g kg^?1 of alginate. Growth rates were 13.7 ± 2.1, 2.1 ± 2.8 and ?2.4 ± 2.9 g kg^?1 bw day^?1, for octopuses fed CON, GEL and ALG diets, respectively. DGs of octopuses had higher concentrations of fatty acids (FA) than the mantle. DG of animals fed CON had higher concentrations of FAs than those fed the artificial diets. Energetic balance demonstrated that physiologically useful energy for maintenance E(B) was affected by type of diet, with negative values of E(B) in animals fed ALG and positive (85 and 154 kJ kg^?1 day^?1) in octopuses fed GEL and CON, respectively. The ALG diet did not cope with the physiological requirements for octopus growth.     

Relationship between nutritional and rearing parameters of Octopus maya juveniles fed with different rations of crab paste

To study the effect of feed ration on rearing and nutritional conditions of Octopus maya juveniles (7–10 days old), two groups of octopuses were fed on 10% and 30% rations, using a crab paste agglutinated with gelatine, when compared to another control group fed ad libitum on crab muscle tissue. The agglutinated diet was well accepted by the octopuses at this early stage. When considered together, the marginally higher survival of the 30% group and probably higher levels of the other rearing performance parameters (growth and feeding rate) indicate that this feed ration is more adequate than a 10% feed ration for rearing O. maya under these conditions. Octopuses fed 30% also generally showed higher total energy per gram of arm tissue and oxygen consumption, as well as different proteolytic activity. In addition, the mentioned nutritional differences influenced by the feed ration were found to be statistically correlated to the promoted growth and the end survival and feeding rates.     

Evaluation of two anaesthetic agents and the passive integrated transponder tagging system in Octopus vulgaris (Cuvier 1797)

Octopus vulgaris is a species of demand in the market with the potential to diversify European aquaculture. However, this species develops complex social interactions under culture conditions, which may have negative effects on its growth, survival and profitability. In order to understand its behaviour under such conditions, individual tagging systems allow a careful evaluation of biological parameters, such as growth and longevity. The present work describes a combined protocol (anaesthetic and tagging) for implanting subcutaneous passive integrated transponder tags (PIT). The effect of two anaesthetic agents in facilitating octopus handling is assessed: clove oil at 20–40–100 mg L^?1 and ethanol (96%) at 1–1.5–2%. The most suitable body location of PIT tags, its effect on growth and mortality, the addition of a stitch and the PIT retention rate after 2 months in floating cages were evaluated. It was concluded that immersion in seawater with 1.5% of ethanol at 22.3±0.5 °C is a suitable anaesthetic for this species. The results showed that the best‐selected PIT body location was the upper left arm III. No effect of the PIT tagging system was found on growth and survival when tagged and untagged octopuses were compared. It was observed after 2 months that the stitch did not induce an increase in the retention rate and 81–100% tag retention regardless of the dietary treatment.