微生态制剂在鱼、虾养殖中的应用

为探讨微生态制剂在鱼、虾养殖中的应用,采用理论结合实践的方法,立足微生态制剂定义与分类,阐述了鱼、虾养殖中使用微生态制剂的必要性,并通过试验分析法,分析了微生态制剂的应用要点和效果,并提出鱼、虾养殖中使用微生态制剂的展望和建议.分析表明,将微生态制剂用于鱼、虾养殖,能够改善水质、抑制有害微生物生长、减少疾病发生、促进生物营养物质转化和吸收等,值得在鱼、虾养殖中大力推广和应用.

超高效液相色谱—串联质谱法测定鱼、虾中4种抗病毒药物的残留

建立同时测定鱼、虾中金刚烷胺、金刚乙胺、美金刚和吗啉胍4种抗病毒药物残留的分散固相萃取—超高效液相色谱—串联质谱法。样品采用1%的三氯乙酸和1%乙酸乙腈提取(1∶9,体积比),经PSA粉、C18粉、中性氧化铝分散固相萃取净化,内标法定量。检测结果表明,4种抗病毒药物的检出限均低于0.8μg/kg,定量限均低于1.0μg/kg,空白鱼、虾中分别添加1.0、10.0、50.0μg/kg,4种抗病毒药物的回收率为86.0%~98.5%,相对标准偏差小于8%。该方法基质干扰小、灵敏度高、回收率好,可用于日常鱼、虾样品中抗病毒类药物的残留检测。

鱼、虾中己烯雌酚残留的高效液相色谱法测定研究

目的:建立了高效液相色谱分析方法对鱼、虾中乙烯雌酚残留进行测定的方法。方法:ODS-C18色谱柱,流动相为0.043 mol/L磷酸二氢钠(调pH5.0)∶甲醇(70∶30),检测波长λ为230 nm,外标法定量。结果:鱼类样品中己烯雌酚在0.03291μg/ml～0.1481μg/ml范围内线性良好,r=0.982164。虾类样品中己烯雌酚在0.03291μg/ml～0.1975μg/ml范围内线性良好r,=0.986136。回收率为99.7%～104.4%;重复进样RSD=0.81%(n=5);方法检出限为2.5μg/kg。结论:高效液相色谱法测定鱼、虾中乙烯雌酚残留,方法简单,回收率和重现性良好,结果准确可靠。

小型湖泊鱼虾蟹综合生态增殖技术规程

结合常熟市湖泊地处苏南地区的气候、生态条件、生产实践和湖泊养殖特性特点,制订了"小型湖泊鱼、虾、蟹综合生态增殖技术规程"。以期为苏南地区湖泊养殖提供参考。

Design and Realization of Cold Disaster Early Warning System for Subtropics Aquaculture

By analyzing the subtropics aquaculture present situation,the necessity of the construction of cold disaster early warning system for subtropics aquaculture,the research goal and the duty were expounded. The system structure and the frame were introduced in detail. Several key questions and their solutions of the cold disaster early warning system for subtropics aquaculture were put forward.

Stock discrimination of spottedtail goby (Synechogobius ommaturus) in the Yellow Sea by analysis of otolith shape

Otolith shape is species specific and is an ideal marker of fish population affiliation. In this study, otolith shape of spottedtail goby Synechogobius ommaturus is used to identify stocks in different spawning locations in the Yellow Sea. The main objectives of this study are to explore the potential existence of local stocks of spottedtail goby in the Yellow Sea by analysis of otolith shape, and to investigate ambient impacts on otolith shape. Spottedtail goby was sampled in five locations in the Yellow Sea in 2007 and 2008. Otoliths are described using variables correlated to size (otolith area, perimeter, length, width, and weight) and shape (rectangularity, circularity, and 20 Fourier harmonics). Only standardized otolith variables are used so that the effect of otolith size on the shape variables could be eliminated. There is no significant difference among variables of sex, year, and side (left and right). However, the otolith shapes of the spring stocks and the autumn stocks differ significantly. Otolith shape differences are greater among locations than between years. Correct classification rate of spottedtail goby with the otolith shape at different sampling locations range from 29.7%–77.4%.

Otolith chemical signatures of spottedtail goby Synechogobius ommaturus in coastal waters of China

This study explores the potential existence of local stocks of Synechogobius ommaturus using otolith chemical signatures. The concentrations of 10 elements （K, Ca, Na, Mg, St, Pb, Ba, Mn, Co, Zn） in the otoliths from eight stocks （Dandong, Dalian, Tianjin, Dongying, Weihai, Qingdao, Ganyu and Xiamen） ofS. ommaturus were measured by Inductively Coupled Plasma Mass Spectrometry and regressed against otolith weight. No significant correlation between otolith weight and concentrations of Na, Mg, Ca, Sr, Co, Ba, Zn and Pb were observed. Concentrations of K and Mn were correlated with otolith weight. Consequently, the residuals of the regressions were used instead of the original concentrations in subsequent analyses. Analysis of variance （ANOVA） showed no significant difference between males and females in otolith chemical signatures. Differences were found among the locations for K, Sr, Mn, Co, Ba, Pb, but not for Ca, Na, Mg and Zn. Residuals of the regressions of elemental concentrations against otolith weight that fitted the normal distribution and homogeneity were studied by discriminant analysis. The success of the discriminant function to predict the location of S. ommaturus capture ranged from 100% for Weihai and Xiamen stocks, to only 44.4% and 62.5% for Qingdao and Dandong stocks, respectively. The average prediction success was 80.3%.

Preliminary Results of Crayfish Distribution and Diseases in Latvia

A lot of water reservoirs offer good natural conditions for crayfish breeding. Today there are four crayfish species present in Latvia--the European species noble crayfish （Astacus astacus）, narrow-clawed crayfish （Astacus leptodactylus）, the North American signal crayfish （Pacifastacus leniusculus） and spiny-cheek crayfish （Orconectes limosus）. In general, crayfish were found in 258 localities--lakes （175）, rivers and streams （66）, reservoirs, ponds and gravel-pits （17）. A. astacus in Latvia is the dominant crayfish species distributed in all regions. Narrow-clawed crayfish was registered since 1960s. North American signal crayfish was introduced due to its resistance to diseases, but spiny-cheek crayfish arrived from Lithuania waters spontaneously. The main threat for crayfish population is crayfish plague, initiated by mucus Aphanomyces astaci. Astacus astacus was more susceptible species in comparison with Pacifastacus leniusculus and Orconectes limosus. Though the North American signal crayfish and spiny-cheek crayfish were not only resistant, they were the carriers of this disease. The physical habitat alterations, pollution and overfishing are significant during the first year breeding period. Crayfish might serve as bacteria carriers and can cause substantial fish diseases （such as aeromonosis, flavobacteriosis）.

Partially or Totally Replacing Fish Meal with Frozen Artemia as a Dietary Protein Source for Early Stage Giant Freshwater Prawn, Macrobrachium rosenbergii Post Larvae Reared under Controlled Conditions

A 105-day feeding study was conducted to evaluate the effect of partial （0%, 20%, 40%, 60% and 80%） and complete （100%） substitution of dietary fish meal （FM） with frozen Artemia on growth performance and feed utilization of Giant freshwater prawn （Macrobrachium rosenbergii） post larvae （PL） reared in fiberglass tanks under controlled conditions. A total of 1080 M. rosenbergii PL, average weight of 6.10 ± 0.4 mg, were equally distributed over 18 fiberglass tanks, （1 m^3 each, and triplicate per treatment）. Six experimental isocaloric （14 MJ/kg/digestible energy） and isonitrogenous （35% crude protein） diets were lbrmulated. Control diet （D1, 100% FM） was formulated with FM as the main protein source （0% Artemia）. Diets D2-D6 were substituted with five dietary protein levels of frozen Artemia （20%, 40%, 60%, 80% and 100%）, respectively. Results showed that growth performance of M. rosenbergii PL fed different Artemia based diets was either equal or superior to prawn fed control FM diet. In addition, increasing dietary frozen Artemia replacement level from 20% up to 100% led to a significant （P 〈 0.05） increase in survival, growth and feed utilization, which indicate that the essential nutrient requirements needed for M. rosenbergii PL was covering with improving feed satiation of PLs. It could be concluded that frozen Artemia biomass instead of fishmeal in M. rosenbergii PL diets can improve survival rate, growth performance, feed utilization, contributing to reducing the use of FM in practical diets and the nursery phase could be shorter and more profitable.

Study of Caspian Goby Neogobius sp. Karyotype Flexibility from Several Biotops

The karyotype of Caspian goby was studied, which has been identified as Caspian bighead goby-Neogobius gorlap before. The results of cytogenetic analyses have shown that the diploid set of goby varies from 38 to 40 chromosomes, which is different from bighead goby （2n = 43-46）. We assumed that Caspian goby has independence as a species.

Effect of salinity on growth and first sexual maturity of Exopalaemon carinicauda(Holthuis, 1950)

To determine the optimal salinity for growth and first sexual maturity of ExopaIaemon carinicauda, the effects of salinity on growth and reproductive performance of early juvenile prawns of E. carinicauda were evaluated under laboratory conditions. Postlarvae from the same female broodstock were reared at six salinity levels （5, 10, 15, 20, 25, and 30） for 12 weeks. The specific growth rate （SGR） and survival rate （SR） under different salinity levels in the first 6 weeks were calculated and compared. SGR was significantly influenced by salinity. Prawns reared in salinity of 10 grew significantly faster （P〈0.05） than those reared in salinities of 5, 20, 25, and 30. However, ANOVA confirmed that there was no significant effect among the six salinity levels on SR. For the next 6 weeks, the body length （BL）, body weight （BW） at the first sexual maturity, and the age at median sexual maturity （As0） of females were measured and compared. Female prawns reared at salinity of 10 presented significantly shorter A50, but no significant differences among the six salinity levels for BL and BW at the first sexual maturity were observed. Based on the above information, the optimal salinity for growth and first sexual maturity of juvenile E. carinicauda is approximately 10.

Productive Performance of Giant Freshwater Prawn （Macrobrachium rosenbergi） Fed Diet Containing Silkworm Pupae （Bombyx mon~ Replacing for Fish Meal

The productive performance of giant freshwater prawn （Macrobrachium rosenbergii de Man） fed diet containing silkworm pupae （Bombyx mori） replacing for fish meal was conducted by focusing on digestibility, growth performance and feed utilization. Five diets of an isonitrogenous of 35 ：e 1% crude protein and isocaloric of digestible energy of 3,200 ±100 kcal/kg were formulated by using silkworm pupae, 0%, 8.6%, 17.2%, 25.8% and 34.7% by weight, replaced for fish meal. Giant freshwater prawn of 19 ± 2.0 g were stocked at 5 ind./m3 in concrete tank of 2.25 ton for three months. The protein digestibility by pepsin enzyme was evaluated in fish meal, silkworm pupae, soybean meal and shrimp meal. The digestibility was significantly difference （P 〈 0.05）. The protein digestibility of fishmeal and soybean meal was higher than silkworm pupae and shrimp meal. The productive performance of prawn in terms of growth rate and feed utilization were not significantly different （P 〉 0.05）. Therefore, silkworm pupae can be replaced for fishmeal in giant freshwater prawn （Macrobrachium rosenbergii de Man） without any adverse effects on productive performance.

Effects of Ionic Concentrations on Survival and Growth in Polyculture of Litopenaeus vannamei with Oreochromis niloticus in Low Salinity Water

A study comparative of rearing of the Pacific white shrimp （Litopenaeus vannamei） with the Nile tilapia （Oreochromis niloticus） in three earthen ponds （5,600 m^2） with the salinity ranged from 0.5-1.2 ppt and three treatment ponds with salinity of 2-4 ppt by adding brine water into the ponds. Postlarvae 12 （PL12） of L. vannamei were stocked at density of 9 PL/m^2 and after one week the Nile tilapia fingerlings were stocked at density of I fish/m^2. Only pelleted feed were given to the fish during the 196-day rearing period. Shrimps were partially harvested by sieve net at day 80 and 120, and five days later PLI2 were stocked at the rate of 3 PL/m^2. After final harvesting at day 196, the production, body weight and survival from the treatment group were significantly higher （P 〈 0.05） than those of the control group. While the fish production body weight and survival rate from both groups were not significant differences （P 〉 0.051）. The ionic concentration of six major ions （CI, SO42, Ca^2＋, Na^＋, Mg^2＋ and K^＋）, salinity and hardness in the treatment ponds were significantly higher than those of the control ponds （P 〈 0.05）. Moreover, the ionic profiles of the treatment ponds were similar to seawater at the salinity of 2 ppt while only 1 ppt in the control ponds. Results from the study indicated that in order to achieve good growth and survival rate of L. vannamei, brine water should be added into grow-out ponds prior to stocking and during the rearing： period to obtain and maintain the salinity not less than 2 ppt.

Sex roles and sexual selection： lessons from a dynamic model system

Our understanding of sexual selection has greatly improved during the last decades. The focus is no longer solely on males, but also on how female competition and male mate choice shape ornamentation and other sexually selected traits in females. At the same time, the focus has shifted from documenting sexual selection to exploring variation and spatiotemporal dynamics of sexual selection, and their evolutionary consequences. Here, I review insights from a model system with exceptionally dynamic sexual selection, the two-spotted goby fish Gobiusculus flavescens. The species displays a complete reversal of sex roles over a 3-month breeding season. The reversal is driven by a dramatic change in the operational sex ratio, which is heavily male-biased at the start of the season and heavily female-biased late in the season. Early in the season, breeding-ready males outnumber mature females, causing males to be highly competitive, and leading to sexual selection on males. Late in the season, mating-ready females are in excess, engage more in courtship and aggression than males, and rarely reject mating opportunities. With typically many females simultaneously courting available males late in the season, males become selective and prefer more colorful females. This variable sexual selection regime likely explains why both male and female G. flavescens have ornamental colors. The G. flavescens model system reveals that sexual behavior and sexual selection can be astonishingly dynamic in response to short-term fluctuations in mating competition. Future work should explore whether sexual selection is equally dynamic on a spatial scale, and related spatiotemporal dynamics.

Ecological variation along the salinity gradient in the Baltic Sea Area and its consequences for reproduction in the common goby

Although it has become clear that sexual selection may shape mating systems and drive speciation, the potential constraints of environmental factors on processes and outcomes of sexual selection are largely unexplored. Here, we investigate the geographic variation of such environmental factors, more precisely the quality and quantity of nest resources （bivalve shells） along a salinity gradient in the Baltic Sea Area （Baltic Sea, Sounds and Belts, and Kattegat）. We further test whether we find any salinity-associated morphological differences in body size between populations of common gobies Pomatoschistus microps, a small marine fish with a resource-based mat- ing system. In a geographically expansive field study, we sampled 5 populations of P. microps occurring along the salinity gradient （decreasing from West to East） in the Baltic Sea Area over 3 consecutive years. Nest resource quantity and quality decreased from West to East, and a correla- tion between mussel size and male body size was detected. Population density, sex ratios, mating- and reproductive success as well as brood characteristics also differed between populations but with a less clear relation to salinity. With this field study we shed light on geographic variation of distinct environmental parameters possibly acting on population differentiation. We provide insights on relevant ecological variation, and draw attention to its importance in the framework of context-dependent plasticity of sexual selection.

Female mating competition alters female mating preferences in common gobies

Mating decisions can be affected by intrasexual competition and sensitive to operational sex-ratio （OSR） changes in the population. Conceptually, it is assumed that both male and female matecompetition may interfere with female reproductive decisions. Experimentally, however, the focus has been on the effect of male competition on mate choice. In many species with paternal care as in the common goby Pomatoschistus microps, the OSR is often female-biased and female matecompetition for access to available nesting males occurs. Using the same protocol for 3 experi- ments testing the effect of a perceived risk of female mate-competition, I studied female preferences for nest-holding males differing in its nest size （large/small）, body size （large/small）, and nest status （with/without eggs already in nest） and measured mating decisions, spawning latencies, and clutch size. Regardless of the social context, females preferred males with larger nests. A preference for large males was only expressed in presence of additional females. For nest status, there was a tendency for females to prefer mating with males with an empty nest. Here, female-female competition increased the propensity to mate. The results of this study show that females are sensitive to a female competitive social environment and suggest that in choice situations, females respond to the social context mainly by mating decisions per se rather than by adjusting the clutch size or spawning latency. Females base their mating decisions not only on a male＇s nest size but also on male size as an additional cue of mate quality in the presence of additional females.

Can native species crucian carp Carassius auratus recognizes the introduced red swamp crayfish Procambarus clarkii？

Procambarus clarkii is native to the south-central United States （Louisiana） and northeastern Mexico, and is a highly efficient predator that poses a damager to native species after its introduction or invasion. In its natural habitat, P. clarkii consumes Carassius auratus, however, whether C. auratus recognizes P. clarkii as a predator is not yet clear. In laboratory experiments, we investigated whether experienced and inexperienced C. auratus recognize P. clarkii as a predatory threat and the specific sensory modality used by C. auratus to respond to chemical and visual stimuli from P. clarkii. In the chemical stimuli experiment, two kinds of chemical stimuli were used, water from a tub containing P. clarkii previously fed with C. auratus （C. auratus diet cues） and water from a tub containing unfed P. clarkii （P. clarkii cues）. In the visual experiment, experienced C. auratus decreased activity, but inexperienced C.auratus avoided the predator compartment. When C. auratus diet cues were presented, both experienced and inexperienced C. auratus increased the use of shelter, decreased activity in the initial response phase. Compared with the blank treatment, experienced C. auratus responded to P. clarkii cues by decreasing activity; however, inexperienced C. auratus showed no reduction in activity. C. auratus appears to recognize P. clarkii as a predator both through visual and chemical cues. Further analysis revealed that C. auratus may recognize R clarkii visually through the disturbances caused by P. clarkii movement and chemically by detecting conspecific alarm cues in the diet of P. clarkii. The results also indicate that ex- perienced C. auratus can recognize R clarkii by innate chemical cues from P. clarkii, whereas inexperienced C. auratus cannot [Current Zoology 57 （3）： 330-339, 2011].

Behavioral dependent dispersal in the invasive round goby Neogobius melanostomus depends on population age

Biological invasions cause major ecological and economic costs in invaded habitats. The round goby Neogobius me- lanostomus is a successful invasive species and a major threat to the biodiversity and ecological function of the Baltic Sea. It is native to the Ponto-Caspian region and has, via ballast water transport of ships, invaded the Gulf of Gdansk in Poland. Since 1990, it has spread as far north as Raahe in Northern Finland （64~41 ＂04＂N, 24~28＂44＂E）. Over the past decade, consistent indi- vidual differences of behavioral expressions have been shown to explain various ecological processes such as dispersal, survival or reproduction. We have previously shown that new and old populations differ in personality trait expression. Individuals in new populations are bolder, less sociable and more active than in old populations. Here we investigate if the behavioral differentiation can be explained by phenotype-dependent dispersal. This was investigated by measuring activity, boldness and sociability of in- dividually marked gobies, and subsequently allowing them to disperse in a system composed of five consecutive tanks connected by tubes. Individual dispersal tendency and distance was measured. Our results revealed that in newly established populations, more active individuals disperse sooner and that latency of a group to disperse depends on the mean sociability of the group. This indicates the presence of personality dependent dispersal in this species and that it is maintained at the invasion front but lost as the populations get older