翘嘴鳜反季节人工繁殖及苗种培育试验

对来源于鄱阳湖和高邮湖的两个野生翘嘴鳜群体,分别在水泥方池降低温度和减低光照培育以及在池塘网箱按常规培育。结果显示,水泥方池培育的雌鱼,成熟度正常、过熟和流产的比例,鄱阳湖群体为36.7%、40.0%和23.3%,高邮湖群体为40.0%、43.3%和16.7%,而雄鱼精子活力均正常;在池塘网箱培育的雌鱼均已过熟或流产,46.7%的雄鱼精巢完全退化。对成熟度正常和过熟的雌鱼各挑选6尾进行催产试验,正常组的催产率、单位体重产卵量、受精率、孵化率和出苗率均显著高于过熟组。试验共孵化出苗118.7万尾,育成1.3 cm的鱼苗96.3万尾和3~5 cm的鱼种68.1万尾。试验结果表明,采取降低温度和光照,能将翘嘴鳜在江苏地区的人工繁殖期推迟至7月底,从而实现高温期的批量育苗,为鳜鱼的反季节养殖奠定了基础。     

磷形态和pH对剩余污泥磷释放的影响

为了探讨pH对污泥中磷的释放行为的影响,采用SMT(欧洲标准测试组织)法对上海三处污水处理厂的剩余污泥中磷的形态进行了分析,并通过室内模拟实验研究了不同pH条件下3种污泥中的磷在海水中的释放行为。结果表明:3种污泥样品的总磷含量各不相同,污泥有机磷含量低,无机磷是主要赋存形态,占TP(总磷)含量的64.42%~83.01%。各形态磷的相关性分析发现,污泥总磷含量主要受NAIP(非磷灰石无机磷)和AP(磷灰石无机磷)影响。室内试验表明,污泥中的磷在酸性、中性和碱性海水环境下均有释放,相比中性条件,酸性和碱性水质更有利于磷的释放;污泥中磷的释放与磷的形态分布有关,但磷释放量大小并不简单取决于总磷和无机磷的含量。     

西施舌的人工育苗现状及养殖发展前景展望

本文介绍了名贵海产贝类-西施舌Coelomatra antiquata在南海的资源状况、人工育苗技术现状和存在问题，并对其进一步发展应解决的关键技术问题进行了探讨，提出了应研究建立室内立体附苗与稚贝立体培育技术，重点攻克大规格苗种中间培育技术及优化增养殖技术措施等观点，同时对其发展前景进行了探讨和分析。     

Addition of oxytocin to semen extender improves both sperm transport to the oviduct and conception rates in pigs following AI

Oxytocin (OXT) contained in boar semen is known to produce uterine contraction; therefore, we hypothesized that the co‐injection of OXT with sperm would improve artificial insemination (AI) using liquid or frozen‐thawed boar sperm. We initially examined whether OXT added to semen extender improved sperm transport to the oviduct. Although the addition of OXT did not affect the fresh or frozen‐thawed sperm motility or acrosomal integrity, it significantly increased the number of sperm in the oviduct at 6 h after AI injection with OXT, as compared with the control (P < 0.05). Moreover, some sperm were observed in the sperm reservoir of the isthmus in the OXT treatment group, whereas few sperm were observed in the control. When OXT was added to the semen extender immediately prior to AI, the conception rates were significantly higher in both fresh semen and frozen‐thawed semen than in the control group (P < 0.05: liquid, 87.5% vs. 70.5%; frozen‐thawed, 89.8% vs. 75.0%). From these results, we concluded that the addition of OXT to the semen extender assisted in sperm transportation from the uterus to the oviduct, which resulted in improved reproductive performance.     

家蚕种质资源品种的人工饲料摄食性研究

采用山东省蚕业研究所现有低成本人工饲料饲养本所家蚕资源品种,研究其摄食性,结果杂交种优于日系与中系,在收蚁与1龄期间是日系明显优于中系,至3龄起蚕日系的存活率也是明显高于中系,而在2龄期间存活下来的中系家蚕对人工饲料的摄食性优于日系。     

石斑鱼人工育苗技术研究

通过对点带石斑鱼人工育苗生产试验,从饵料准备、环境条件控制、管理措施等方面进行了探索。共培育出规格5～8cm的石斑鱼苗60多万尾。     

Changing of fat content and fatty acid profile of reared pike (Esox lucius) fed two different diets

Fat content and fatty acid profile of two pike yearling groups grown on two different diets were compared. The groups originated from culture on artificial feed. One group (cultured pike fed first pellet then prey‐fish (PF)) was fed with natural food, live prey‐fish, while the other one (cultured pike fed exclusively pellet (PP)) by trout feed through a 3‐month experimental period. Growth of pike was lower with PP than with PF. The trout feed resulted in an increase of the fat content of fillet and the formation of abdominal fat depots. Feeding of natural food decreased the fat content. The proportion of the saturated fatty acids in fillet was higher in the (PF) group. The n‐6 fatty acids (arachidonic C20:4n‐6 and docosatetraenic C22:4n‐6 acids) were lowest in PP‐fed pike. Regarding total n‐3 fatty acids ratio there was no significant difference between the groups, but the level of α‐linolenic (C:18:3n‐3) acid showed significant difference among groups.     

Treatment of shrimp farm effluent with omnivorous finfish and artificial substrates

Long‐term environmental sustainability and community acceptance of the shrimp farming industry in Australia requires on‐going development of efficient cost‐effective effluent treatment options. In this study, we aimed to evaluate the effectiveness of a shrimp farm treatment system containing finfish and vertical artificial substrates (VAS). This was achieved by (1) quantifying the individual and collective effects of grey mullet (Mugil cephalus L.) and VASs on water and sediment quality, and (2) comparing the retention of N in treatment systems with and without the presence of finfish (M. cephalus and the siganid Siganus nebulosus (Quoy & Gaimard)), where light was selectively removed. Artificial substrates were found to significantly improve the settlement of particulate material, regardless of the presence of finfish. Mullet actively resuspended settled solids and reduced the production of nitrate when artificial substrates were absent. However, appreciable nitrification was observed when mullet were present together with artificial substrates. The total quantity of N retained by the mullet was found to be 1.8– 2.4% of the incoming pond effluent N. It was estimated that only 21% of the pond effluent N was available for mullet consumption. When S. nebulosus was added, total finfish N retention increased from 1.8% to 3.9%, N retention by mullet also improved (78±16 to 132±21‐mg N day^?1 before and after siganid addition respectively). Presence of filamentous macroalgae (Enteromorpha spp.) was found to improve the removal of N from pond effluent relative to treatments where light was excluded. Denitrification was also a significant sink for N (up to 24% N removed). Despite the absence of algal productivity and greater availability of nitrate, denitrification was not higher in treatments where light was excluded. Mullet were found to have no effect on the rates of denitrification but significantly reduced macroalgal growth on the surface of the water. When mullet were absent, excessive macroalgal growth led to reduced dissolved oxygen concentrations and nitrification. This study concludes that the culture of mullet alone in shrimp farm effluent treatment systems does not result in significant retention of N but can contribute to the control of macroalgal biomass. To improve N retention and removal, further work should focus on polyculturing a range of species and also on improving denitrification.     

The slow rise of technology: Computer vision techniques in fish population connectivity

1. Technological advancements in data collection and analysis are producing a new generation of ecological data. Among these, computer vision (CV) has received increased attention for its robust capabilities for rapidly processing large volumes of digital imagery.
2. In marine ecosystems, the study of fish connectivity provides fundamental information for assessing fisheries stocks, designing and implementing protected areas and understanding the impact of habitat loss. While the field of fish connectivity has benefited from technological advancements, the extent to which novel techniques, such as CV, have been utilized has not been assessed. To inform future directions and developments, this study reviewed the current use of CV in fish connectivity research, quantified how the implementation of such technology in fish connectivity research compared with other areas of marine research and described how this field could benefit from CV.
3. The review found that the use of remote camera systems in fish connectivity research is increasing, but the implementation of automated analysis of digital imagery has been slow. Successful implementation and expansion of CV frameworks in aquaculture and coral reef ecology suggest that CV techniques could greatly benefit fish connectivity research.
4. A case study of potential use of CV in fish connectivity research, scaling up optimal foraging models to predict marine population connectivity, highlights how beneficial it could be.
5. The capacity for CV techniques to be adopted alongside traditional approaches, the unparalleled speed, accuracy and reliability of these approaches and the benefits of being able to study ecosystems along multiple spatial–temporal scales, all make CV a valuable tool for assessing connectivity. Ultimately, these technologies can assist data-driven decisions that directly influence the health and productivity of marine ecosystems.

     

人工诱导池塘养殖鳗鲡成熟产卵以及胚胎和仔鱼发育

降海鳗鲡一直是作为研究鳗鲡人工繁殖的材料,由于降海鳗鲡的资源衰退,选用池塘养殖鳗鲡作为亲本的研究成为热点。尽管人工诱导野生降海鳗鲡获得的胚胎发育过程的研究已报道,但人工诱导池塘养殖鳗鲡的胚胎及仔鱼早期发育未见报道。本文应用池塘养殖日本鳗鲡取代野生降海日本鳗鲡进行人工繁殖,2002年的孵化批次共80次,其中大部分为人工授精卵(60次),一部分(20次)为自然产卵。受精率为(44.03±21.99)%,孵化率为(65.76±19.48)%,共计获得苗种349.9万尾。连续记录了鳗鲡的胚胎和早期仔鱼的发育过程。在水温为20.5℃时,胚胎发育需要时间为49h,所需积温1005℃.h;在水温为22.5℃时,胚胎发育需要时间为39h,所需积温878℃.h;在水温为24.5℃时,胚胎发育需要时间为34h,所需积温833℃.h。