渔场鱼量的稳定与捕获量关系的优化设计

本文给出在保持渔量稳定条件下获得最大捕获量的优化模型，并对模型进行了一定的探讨，对渔场的实际操作具有一定的指导意义．

内水体鱼量测定法

在经常变化的外因里，其中包括人类起源的因素的环境里，有必要更精确地了解鱼的贮存量。在此基础上，计算出经营用量和确定采取旨在提高水体鱼产量的必要措施。

基于声学摄像仪的溯河洄游幼香鱼计数

至今主要靠目视计数来掌握香鱼(Plecoglossus altivelis)的资源量,这种方法很耗劳动力且精度低。由华盛顿大学研发的声学摄像仪DIDSON(Dual-frequency IDentification SONar)可在浑浊不清的水中摄取接近光学视频画质的图像。其附带软件虽可对体长为几十厘米的大个体鱼计数,但对于体长6cm以下的小个体鱼,由于其回波信号弱,计数显得非常困难。本文提供了一种基于DIDSON的溯河洄游幼香鱼计数的新方法。首先从声学图像中消除静止的背景,提取出运动目标并除去噪音像素,然后用卡尔曼滤波器对剩下的目标进行跟踪,根据目标移动的特性把目标分为香鱼和垃圾2大类,在除去向下游移动的垃圾之后,可正确地计算向上游移动香鱼的数量。通过现场实测验证了上述声学计数方法的实用性和高效性。

基于水声多波束技术的深水网箱鱼群状态远程监测仪研究

针对离岸深水网箱养殖的鱼群安全问题,提出了一种基于水声多波束技术的鱼群状态监测新方法。该方法采用环形水声多波束阵在深水网箱中进行分区探测,结合多路声信号处理技术、数据无线传输技术和虚拟仪器技术,实现了深水网箱中鱼群状态的远程、实时监测。与传统电机旋转扫描方法比较,该方法结构简单、功耗小,探测速度快,完成一次全网箱探测只需4 s;采用回波能量积分算法估计鱼群量,偏差值小于25%。监测仪样机在海上易于安置、操作方便;在福建泉州围头海域深水网箱养殖现场不同的海况条件测试中性能稳定、可靠。

深水网箱多波束水声鱼群状态监测仪的改进设计

针对离岸深水网箱养殖的鱼群安全问题,采用多波束水声技术监测鱼群状态的方法。结合信号处理技术、通用分组无线业务(GPRS)无线传输技术及串口通信技术,开发了一套多波束水声鱼群状态监测仪。监测仪完成1次网箱扫描只需5 s;实现了监测数据的即采即发功能,提高了系统的实时性;改进了电路结构,降低了系统复杂度,减小了系统体积,降低了成本。试验表明,监测仪操作简便,性能稳定,能有效完成深水网箱的实时监测任务。

渔业资源的变动模型与捕捞策略

为描述鱼群中鱼量在复杂因素影响下的变动规律,建立了定量化的数学模型,并给出定率捕捞、分段减率、集中峰率等3种可操作的捕捞策略,提供了在可持续生产的条件下,寻求最大收获量及其决策数据的计算公式与搜索算法。该算法简便易行,既适用于单年生产,也适用于多年承包。最后,对各种捕捞策略做出了定性评价。

Real-time Quantitative PCR Analysis of Vascular Endothelial Growth Factor Receptor-2(VEGFR-2) Expression at Zebrafish Different Developmental Stages

[Objective]To investigate the expression of zebrafish vascular endothelial growth factor-2（VEGFR-2） at different developmental stages.[Method]Total RNAs were extracted from 12,24,48,72 and 96 hpf stage zebrafish embryos and larvae.Real-time quantitative RT-PCR was performed to examine the expression of VEGFR-2.The data were analyzed by 2^-△△Ct method.[Result]The expression level of VEGFR-2 gene increased gradually from 12 to 72 hpf,and subsequently decreased at 96 hpf.The expression level was lowest at 12 hpf,highest at 72 hpf,and had significant differences when compared with that of other developmental stages.[Conclusion]The expression level of VEGFR-2 increases gradually before blood vessel maturation and decreases as blood vessels mature.

The Catch Distribution of Ommastrephes batramii in Squid Jigging Fishery and the Relationship between Fishing Ground and SST in the North Pacific Ocean in 2004

Neon flying squid Ommastrephes batramii is widely distributed in the North Pacific Ocean, which has become the main fishing species for Chinese squid jigging fleets since 1993. Many authors have made the studies on the fields of fishing ground and its environment conditions. However, the squid catch per fishing vessel attained the highest level of about 550 t in 2004. In this paper, the catch and its distribution in 2004 would be compared with the previous year. Based on the catch data from Chinese squid jigging vessels and sea surface temperature with the format of 1 °latitude by 1 °longitude from May to November in 2004, the distribution maps were drawn by Marine explorer 4.0. The results show that the production in the east waters to 160°E was low during May and July. During October and November, the production in the waters from 150°E to 160°E was relatively higher, which occupied 62.5 percent of the total catch. During November, the production in the west waters to 150°E was also low. The highest CPUE area located in the west waters to 150°E, the next was the area from 150°E to 160°E and the lowest CPUE area located in the east waters to 160°E. The SST in the fishing ground seems to change seasonally. The suitable SST for each month is as follows： 12-14 ℃ in May, 15 ℃ - 16 ℃ in June, 14 ℃ - 16 ℃ in July, 18 ℃ - 19 ℃ in August, 16 ℃ -17 ℃ in September, 15 ℃- 16 ℃ in October and 12 ℃ - 13 ℃ in November. The result of K-S test shows that the above monthly suitable SST is considered as the indicator of looking for the main fishing ground.

Study on the Morphological Differences of Four Carp Populations

[Objective] The aim was to discuss the morphological differences of four carp populations.[Method] Based on traditional morphological data（including countable and measurable characters） and framework data,the morphological differences and phylogenesis of Yellow River carp population（YR）,wild four-naris carp population（WF）,farmed four-naris carp population（FF） and carp population from Suzhou section of Wusong River（WR） were studied by means of multivariate analysis.[Result] There was no significant difference（P〉0.05） in countable characters among four carp populations.Discriminant analysis showed the discriminating accuracy of YR,WF,FF and WR population were 87.5%,78.1%,73.5% and 96.8% respectively,and the synthetic discriminating accuracy of four populations was up to 83.7%.In addition,cluster analysis revealed that YR population and WF population clustered together,while FF population and WR population clustered together.Principal component analysis indicated that the morphological differences among four populations mainly came from the head,tail and vertical axis of fish.[Conclusion] The study could provide theoretical foundations for the purification and rejuvenation of rare four-naris carp.

Analysis of Molecular Weight Distribution and Antioxidant Activities of Cirrhinus molitorella Skin Collagen Hydrolysates

[Objective] The aim of this work was to identify molecular weight （MW） distribution and antioxidant activity of fish skin col agen hydrolysates. [Method] The MW distribution of hydrolysates was determined using both size exclusion chromatography and matrix-assisted laser desorption ionization time-of-flight mass spec-trometry （MALDI-TOF-MS）. Fish skin were treated by the alkaline protease 2709. [Result] The optional conditions for hyerolysis were time 3 h, temperature 55 ℃, pH 10.0, substrate concentration 80 g/L and E/S 4%. The results of both methods indi-cated that the molecular weight of col agen hydrolysates was from 400 to 1 800 Da, and the peptides’ molecular weight was less than 1 400 Da mostly. The reducing power and antioxidant/radical scavenging activity [1, 1-diphenyl-2-picryl-hydrazyl （DPPH） free radical scavenging activity] were determined. [Conclusion] The results reveal that the fishskin hydrolysate is a potential source of antioxidants.

Growth Performance of Hybrid Progenies of Grass Carp (Ctenopharyngodon idella) Populations from Different Geographical Origins

[Objective] This study aimed to evaluate growth performance of hybrid progenies of 10 grass carp （Ctenopharyngodon idella） populations from different ge- ographical origins （Foshan population, Zhaoqing population, Jingzhou population 1, Jingzhou population 2, Jingzhou population 3, Ezhou population, Yiyang population, Changsha population 1, Changsha population 2 and Jiangsu population）. [Method] Fifteen hybrid combinations were established with these ten grass carp populations and cultured in the same pond. The body mass of hybrid progenies was measured at the age of 4, 7, 8, 10, 12, 15 and 18 months, respectively. Using body mass at the age of 4 months as a concomitant variable, the growth performance of proge- nies from different hybrid combinations was analyzed by covariance analysis. [Re- suit] The average body mass of hybrid progenies of Jingzhou population 2 c2 x Foshan population $ reached the maximum （1 892.90 g） at the age of 18 months, which was 3.51%-32.36% higher than that of other hybrid progenies. Multiple com- parison analysis showed that average body mass of hybrid progenies of Jingzhou population 2 2 x Foshan population ♂ and Jingzhou population 1 ♀× Foshan population ♂ was significantly higher than that of other hybrid progenies （P〈0.05）. [Conclusion] In the production process, Jingzhou population 2 ♀ × Foshan popula- tion 5 and Jingzhou population 1 ♀×Foshan population ♂ can be used to pro- duce high-quality fries, thereby greatly improving economic benefits. This study laid the foundation for establishment of rapid-growing grass carp core populations.

Effect of Carbohydrate Content in Feed on the Daily Metabolic Rate of S. meridionalis

The routine metabolic rate in southern catfish juvenile(24.3-250.8 g)fed with saccharine feed(CHO)was measured in this study.Fish were fed with iso-nitrogenous(40 % crude protein)and iso-lipidic(10% crude lipid)experimental feed containing 0(control feed),15%,30% of carbohydrate level.The routine metabolic rates of 15 % and 30% dietary carbohydrate group were significantly higher than that of 0% dietary carbohydrate group.The relationship between body mass(Wt)and routine metabolic rate(Rr)of southern catfishfed with different test feed could be described as:(1)0% CHO:ln(Rr)=0.986 ln(Wt)+1.419 r2=0.922,n=25,P<0.001;(2)15% CHO:ln(Rr)=0.912 ln(Wt)+1.741 r2=0.966,n=21,P<0.001;(3)30% CHO:ln(Rr)=0.762 ln(Wt)+2.378 r2=0.958,n=21,P<0.001.The intercept was increased and mass coefficient was decreased with the increase of carbohydrate level in feed.It could be concluded that southern Silurus meridionalis had poor metabolic capacity which led the increase of routine metabolic rate of fish with small size.But with the increase of body size southern Silurus meridionalis might had a better adaptation to high carbohydrate concentration.

A HPLC Method for the Determination of Salmon Calcitonin in Injection by Gradient Elution

It was concluded that the described HPLC method could be used for the assayof salmon calcitonin in injection, as it offers qualified selectivity, accuracy and precision ofanalysis.

有毒污水泛滥 受罚三万元

我市郊区窑坡渡乡，有一座小型水库，名叫蚕桑水库，水面为80余亩，水库有深有浅，年平均水深在三米以上，集雨量面积较大，水质肥爽，鱼类饵料来源丰富，年产鱼47000多斤，亩平产鲜鱼585斤。同时，库区无杂物，易于捕捞，是我市郊区产鱼量最高的唯一水库。

Quantitative Allocation Analysis of "Raising by Planting" System Combining Fruits and Poultry for Mountainous Region in Headwaters of Dongjiang River

[Objective] The aim was to promote nutrient cycling and utilization in the mountain＇s system combining fruits and poultry and to control non-point source pollution produced from swine raising and navel orange planting in headwaters of Dongjiang River. [Method] The quantitative analysis was mainly conducted for the so called ＂raising by planting＂ which is about material cycle in ＂pig-methane-fruit-fish＂ model and energy cascade utilization, based on relationship between excreted amount by livestock and the utilized quantity in Xinlin Farm in Longtang Town, Dingnan County, Jiangxi Province. [Result] Considering N requirement by fruit trees, a navel orange orchard （1 mu） could support about 2.72 pigs, the equipped biogas pool （1.88 m3） could support 1 166.67 kg of duckweeds and a fish pond could support 25.57 grass carps. In contrast, a satsuma orchard （1 mu） could support about 1.96 pigs, the equipped biogas pool （1.35 m3） could support 841.53 kg duckweeds and the fish pond could support 18.44 grass carps. [Conclusion] The results provided scientific references for quantitative allocation of members in ＂pig-methane-fruit-fish＂ model when popularized in headwaters of Dongjiang River.

Importance of Weighting for Multi-Variable Habitat Suitability Index Model: A Case Study of Winter- Spring Cohort of Ommastrephes bartramii in the Northwestern Pacific Ocean

Weighting values for different habitat variables used in multi-factor habitat suitability index (HSI) modeling reflect the relative influences of different variables on distribution of fish species. Using the winter-spring cohort of neon flying squid (Ommastrephes bartramii) in the Northwestern Pacific Ocean as an example, we evaluated the impact of different weighting schemes on the HSI models based on sea surface temperature, gradient of sea surface temperature and sea surface height. We compared differences in predicted fishing effort and HSI values resulting from different weighting. The weighting for different habitat variables could greatly influence HSI modeling and should be carefully done based on their relative importance in influencing the resource spatial distribution. Weighting in a multi-factor HSI model should be further studied and optimization methods should be developed to improve forecasting squid spatial distributions.

Monthly variation in the fat content of anchovy (Engraulis japonicus) in the Yellow Sea: implications for acoustic abundance estimation

Anchovy is a key species in the Yellow Sea ecosystem. An accurate estimate of anchovy abundance is vital for the management of the anchovy stock and measurement of the ecosystem response to changes in anchovy abundance. However, the acoustic fish abundance estimate may be biased by 30%-40% if the fat-content induced target strength variation is not taken into account. We measured the monthly variation in the fat content of anchovy (Engraulis japonicus) in the Yellow Sea, and evaluated the potential effect of variation in fat content on the acoustic assessment of anchovy abundance. The fat content of anchovy varied seasonally, with two maxima and two minima in a year. The highest fat content (14.75%) was measured in the pre-spawning period in May, and the lowest fat content (2.48%) was measured during the post-spawning period in October. Fat content appeared to correlate with water content, but not body size. Assuming that the target strength is decreased by 0.2dB for every 1% increase in fat content, the seasonal difference in the target strength of anchovy may be as high as 2.45 dB. Given this, the acoustic abundance estimate may be biased by between 43% and 76%. Our results highlight the need for more information on the changes in fat content of fishes whose abundance is estimated by acoustic surveys.

Measurement of single-fish target strength in the South China Sea

We measured the target strength （TS） of three commercial fish species： whitespotted spinefoot （Siganus canaliculatus）, black porgy （Acanthopagrus schlegelii）, and creek red bream （Lutjanus argentimaculatus）, in the South China Sea. The TS of caged or tethered fish （n=76 total） was measured using a Simrad EY60 portable scientific echosounder at 120 kHz. We evaluated the relationship between TS and total length （TL, cm） for the three species. This is the first attempt to use split-beam acoustics to measure single-fish TS in the South China Sea by Chinese researchers. Our results will improve the accuracy and precision of acoustic abundance estimates of commercially important species and fi.trther the development of underwater acoustic survey techniques in fisheries in the South China Sea.

Effects of Dietary Protein Level on Growth and Utilization of Protein and Energy by Juvenile Mangrove Red Snapper(Lutjanus argentimaculatus)

A feeding trial was conducted in a recirculating water system to investigatethe effects of dietary protein levels on growth, feed utilization, hepatosomatic index and liverlipid deposition of juvenile red snapper, Lutjanus argentimaculatus (average initial wet weight 8.0± 0.39 g and total length 3.14 ± 0.3 cm). In the experiment, six fishmeal-based diets wereformulated to contain various protein levels (20% to 45% in 5% increments), with dietary energyranging from 2210.7kJ100g to 2250.2 kJ 100g dry matter. The protein to energy ratios of diets rangedfrom 8.58 mg protein kJ^(-1) to 20.03 mg protein kJ^(-1). Diets were fed for 90 d to triplicategroups of fish stocked in 0.128 m^3 seawater tanks, 25 individuals each. The daily ration of 2% wetbody weight was offered to the fish thrice a day. The fish at the end of the study had more thanten-fold (77.0 g) increase in weight compared to the initial (8.0 g). Fish fed diets of 40% and 45%protein produced significantly (P【0.05) higher weight gain of 77.2 g and 76.5 g, and specific growthrate (SGR) of 2.65% and 2.62% than those of 67.0 g and 68.3 g, and 2.49% and 2.51% of the otherdiets. The broken-line regression of SGR against dietary protein level yielded an optimum dietaryprotein requirement of 42.6% (Y = - 1.6295 + 0.1114 X^2, P【0.05). Survival remained 100% amonggroups. Feed conversion ratio decreased from 0.45 for fish fed 20% dietary protein to 0.35 for fishfed 45% dietary protein. Nitrogen intake increased with an increase in dietary protein, which inturn resulted in an increase in nitrogen gain of fish whole body. Fish fed 40% and 45% protein dietsshowed higher (P【0.05) nitrogen gain (0.27g and 0.26g) than those (0.23g and 025g) fed all otherdiets. Gross energy intake (GEI) in fish fed 45% protein was lower (600.67kJ) than that (607.97 kJ)of 40% protein diet, though the differences were not statistically significant (P】0.05); GEI rangingfrom 677.31 kJ to 663.20 kJ at remaining four diets (20% to 35% protein) did not appear to differsignificantly (P】0.05). The highest energy gain of 518.33 kJ was obtained with fish fed 40% protein,resulting in the highest energy retention efficiency of 85.26%. The hepatosomatic index of fish feddiets of 20%, 25%, 30% and 35% protein were significantly (P【0.05) higher (2.09% to 2.57%) thanthose (1.44% and 1.41%) of fish fed diets containing 40% and 45% protein. Liver lipid contentsdecreased from 8.72% to 7.0% in fish fed dietary protein of 20% to 45% in 5% increments. Resultssuggest that the diet containing 40% to 42.6% protein with a P/E ratio of 17.6 mg protein kJ^(-1) isrequired for good growth of L. argentimaculatus weighing between 8.0 g and 85.2 g under the cultureconditions of the present study.

Effect of Dietary Phosphorus on the Growth and Body Components of Juvenile Synechogobius hasta

The effect of dietary phosphorus on the growth and body components of juvenile Syechogobius hasta was determined. Different percentages of dietary phosphorus （0.63, 0.77, 0.93, 1.06, 1.22 and 1.36） were tested by feeding the fish （body weight, 15.81 ±：0.32 g; 20 individuals each group; 3 groups each percentage） at a surplus of 5%-10% above satiation for 35d. Dietary phosphorus did not significantly affect the specific growth rate, teed intake, feed conversion ratio and protein efficiency rate. Nitrogen retention was lbund to be the highest in fish fed the diet contatimg 1.06% of phosphorus; however, this was not significantly different from other diets. Fish ted the diet containing 0.93% of phosphorus showed the highest phosphorus retention; similar phosphorus retention rates were found in fish fed the diets containing 0.77% and 1.06% of phosphorus. Fish fed the diet containing the highest percentage of dietary phosphorus were found to contain the least whole body lipid, lower than fish fed other diets （P〈0.05）. The protein content increased from 18.59% to 19.55% （although not significant） with the decrease of body lipid content （P〉0.05）. The contents of the whole body ash, whole body phosphorus and vertebrae phosphorus increased with dietary phosphorus percentage up to 1.06 （P〈0.05）, reaching a plateau after that. Dietary phosphorus did not significantly influence the muscle components （protein, lipid and moisture）. Condition factor and hepatosomatic index were the highest in fish fed the diet containing 0.63% of dietary phosphorus; however, this was not significantly different from those of other diets. The second-order polynomial regression of phosphorus retention against dietary phosphorus identified a breakpoint at 0.88% of dietary phosphorus. However, the dietary requirement of phosphorus for maintaining maximum phosphorus storage determined by broken-line analysis of the contents of whole body phosphorus, and ash and vertebrae phosphorus was 1.06% of the diet.