A numerical simulation of cool/wet and warm/wet episodes in the western United States

Wintertime precipitation in the mountains of the western United States during a warm or cool period has a pronounced influence on streamflow. During a warm year, streamflow at intermediate elevations responds more immediately to precipitation events; during a cold year, much of the discharge is delayed until the snow melts in spring and summer. Previous efforts at studying these extremes have been hampered by a limited number and length of observational analyses. In this study, we augment this limited observational record by analyzing a simplified general circulation model.

Effect of stocking density on the growth of Thai pangas, Pangasius sutchi (Fowler) in net cage fed on formulated diet

A three month long experiment was conducted to observe the effect of stocking density on the growth of Pangasius sutchi in net cages. The size of each cage was 1m³.The three stocking densities used were 40, 50 and 60 fishes/m³ and designated as treatment T1, T2 and T3 respectively. Each treatment had three replicates. All the fishes were of same age group having mean length and weight of 7.13 ± 1.37 cm and 2.46 ± 0.12 g respectively. The fish in all the net cages were fed a diet containing 34% protein. The result of the study showed that fish in the treatment T1 stocked at the rate of 40 fish/m³ resulted the best individual weight gain followed by T2 and T3 respectively. The specific growth rate (SGR) ranged between 3.51 and 3.09, the food conversion ratio (FCR) values ranged between 1.73 and 2.04 with treatment T1 resulting the lowest FCR. The protein efficiency ratios (PER) values were 1.69, 1.16 and 1.43 for treatment T1, T2 and T3 respectively. There was no significant (P>0.05) variation among the survival rates of fish which ranged between 92 and 95%. The net productions in different treatments were 2189, 2343, and 2283g for treatment T1, T2 and T3 respectively. The result of the present study indicated that the best individual growth of P. sutchi was obtained at a density of 40 fish/m³ but the highest total production was obtained at a stocking density of 50 fish/m³ in net cages.

不同年代推出的冬小麦(Triticun aestivum L)品种农艺性状以及光合生理生态特性

本文探讨了五十年来北京地区广泛推广的17个冬小麦(Triticun aestivum L)品种在品种改良的过程中农艺性状和某些光合特性的变化趋势。从中选出形态、产量和推出年代差异最大的3个冬小麦品种：京冬8号、农大139和燕大1817，种植在相同的环境条件下，进一步研究与冬小麦产量提高有关的生理生态特性，以及它们的气体交换特性对于外界环境变化的响应。本试验于1999-2001年在北京农林科学院试验农场（39o09’N, 116o04’E）进行。结果如下： 1. 在冬小麦品种改良的过程中，小麦品种的经济产量、收获指数、千粒重提高，而生物产量、株高、单株穗数、单株籽粒产量和穗长降低。籽粒产量与株高、穗数极显著负相关，与穗粒重、收获指数、千粒重极显著正相关。株高与穗长、单株籽粒产量、穗数显著正相关，而与收获指数和千粒重极显著负相关。收获指数与穗数极显著负相关，而与千粒重极显著正相关。说明株高降低、收获指数提高和千粒重的提高对于冬小麦品种改良过程中产量的提高起重要作用。 2. 随品种推出年代的延迟，各品种苗期-拔节期的净光合速率（PN）、 气孔导度（gs）、蒸腾速率（ E）、量子产率（Fv/Fm）均呈增加的趋势，水分利用率（WUE）呈降低的趋势。在孕穗期-蜡熟期，旗叶的PN也随品种推出年代而呈增大的趋势，而在成熟期呈减小的趋势。gs在孕穗期-灌浆期增大，在蜡熟期和成熟期减小;各个时期的E均呈递增趋势;而WUE呈降低趋势。旗叶的Fv/Fm在孕穗期和开花期呈递增的趋势，而在成熟期下降。在苗期至孕穗期，PN、 E均与产量显著正相关;在拔节始期和孕穗期gs与产量显著正相关（R=0.616, 0.499, P<0.05），在苗期-拔节期、开花期和成熟期，WUE与历史产量和试验产量显著负相关（P<0.05, 或P<0.001），在苗期和拔节期Fv/Fm与产量正相关（P<0.05）。在冬小麦品种的改良过程中，其光合作用的改良不仅表现在净光合速率上，而且还表现在荧光动力学参数Fv/Fm上， 即PSII的原初光能转化效率有所提高。 3. 孕穗期至灌浆期，高产品种京冬8号旗叶的PN、gs、E、叶绿素含量和水分含量均最高，而水分利用率（WUE）较低，且具有较高的光呼吸和较低的暗呼吸，其旗叶的叶比重也较高。京冬8号（上世纪90年代推出）叶片气体交换的日变化表现为：在拔节期，全天的净光合速率均最高，而后随生育进程差异变小，通常上午较高，而在中午和下午较低。其旗叶Fv/Fm的变化趋势与净光合速率相似。燕大1817（上世纪40年代推出）的光合作用的午休现象较不明显，且在下午恢复较快，说明它可能具有一定的抗光抑制能力。孕穗至灌浆期是冬小麦籽粒形成和充实的关键时期，此时，叶片光合产物充足与否直接影响千粒重。进一步研究它们“源库”关系的结果表明，京冬8号“源库”关系协调，能够充分发挥“源“和“库”的潜力，且具有最高的收获指数、穗粒重和千粒重，而其它两个品种燕大1817和农大139都存在提高其品种产量潜力的限制因素。因此我们认为，高产品种的高产不仅因为其叶片具有较高的光合速率和较低的暗呼吸消耗，而且有较大的“库”容量和收获指数。 4. 当CO2浓度从360增加到720 µmol.mol-1时，单位叶面积的净光合速率和叶片的水分利用率 随CO2浓度升高而升高。但不同品种差异很大，京冬8号PN 和WUE最高，增加最多，分别提高了173 %和81 %;其次为农大139（上世纪70年代推出），燕大1817增加最少，分别提高了76 %和65 %。E随CO2 浓度的增加而提高;农大139和燕大1817的gs随CO2浓度的增大而减小，而京冬8号则增大。京冬8号和农大139旗叶胞间CO2浓度（Ci） 随CO2 浓度的增加而增大，而燕大1817 的Ci先增大，而后又急剧降低，且京冬8号的Ci最低，燕大1817 最高。在高CO2浓度下，京冬8号的光合速率显著高于其它两个品种，而Ci却低于其它两个品种，说明京冬8号的光合潜力高于其它两个品种。灌浆期高产品种京冬8号旗叶在田间不同自然光强下，净光合速率都是最高的（差异最大时，比燕大1817提高24.8 %）。因此，冬小麦光合作用的潜力，也在一定程度上得到改良。

Elevating fishers of Dal Lake in Jammu and Kashmir

The deteriorating condition of one of the most magnificent lakes of India, the Dal Lake, has provoked a lot of research interest from the biological and ecological points of view. However, the impact of deterioration of the ecology on the inhabitant fisher folk around Dal Lake has not been given much importance. In this study, the three major beats of the lake, namely, Hazratbal, Nishat and Nehru Park, were surveyed, randomly taking 10% of the fishermen families. It was observed that the summer mean catch per day (5.18 ± 0.69 kg) was more than the mean winter catch per day (2.85 ± 0.40 kg). However, the total annual catch per person was only 1195.56 ± 211.63 kg. Moreover, marketing through middlemen, especially, during summer, was observed to be very low fetching in terms of mean price per kilogram fish, amounting to Rs 37.50 ± 2.54 for local fish and Rs 22.50 ± 2.88 for the carp. It was also observed that the fisher folk had borrowed a good amount of money for the repair and construction of their houses and boats. Therefore, on the whole, the fishing business around Dal Lake was observed to be under severe stress. In this context, this paper has come out with recommendations to uplift the socio-economic conditions of the fishers.

National report of the frame survey 2006 in the Ugandan part of Lake Victoria

Fisheries Frame surveys have been carried out on Lake Victoria biannually since 2000 to determine· the number of fishers, fish landing sites, facilities at the landing sites. Information on the composition fishing crafts, their mode of propulsion, fishing gears and the fish species they target is also collected. This information is used to guide development and management of the lake's fisheries. The results of the four surveys carried out since 2000 show that the number of landing sites has decreased by 24% from 597 in 2000 to 481 in 2006, mainly as result of reorganisation of landing sites into Beach Management Units (BMUs). The fish landing sites continue to have inadequate facilities to service the fisheries industry e.g. in the 2006 survey only 11.2% of landing sites had fish shades; <0.6% had cold rooms; 3.5% had electricity; and only 35.5% had toilet facilities. Similarly, only 11.4% of landing sites had portable water; 2.5% had jetties, 3.7% had 'fish stores; and 36% were accessible by all weather roads. There is need to improve facilities servicing fisheries at landing sites, with major emphasis on sanitary facilities, especially toilets and portable water. The BMUs should be sensitised to prioritise the construction and utilisation of public toilet facilities at their respective landing sites. The ultimate aim should be to have public toilets at all fish landing sites. The trend of the various indicators of fishing effort has continued upwards: The total number of fishers increased by 43.5% from 37,721 in 2004 to 54,148 in 2006 and the number of fishing crafts increased (43.9%) from 16,775 in 2004 to 24,148 in 2006 over the same period. The total number of gillnets increased by 28.6% from 458,597 in 2004 to 589,777 in 2006 and the number of long line hooks increased by 136% from 968,848 to 2,285,609. The number of fishing crafts using outboard engines also increased from 3,173 in 2004 to 5,047 in 2006 suggesting that more fishers were going far in search of fish. There is still a large number of illegal gears especially beach seines, which increased by 58.8% from 954 in 2004 to 1420 in 2006. Efforts to remove these very destructive gears should be stepped up. There was also larger increase in number of illegal gillnets <5 inch mesh size. These increased by 63% from 56,246 in 2004 to 91,740 in 2006 compared with 23.8% increase of gillnets ~5 inch mesh size. There were also large increases in the numbers of gillnets of 5 and 5% inch mesh size, which increased by 48% and 130% from 2004 to 2006 implying a trend towards use of smaller gillnet mesh sizes. The number of traps which are used in shallow vegetated areas, flood plains and river mouths to target tilapiines and riverine species decreased drastically from 5,361 traps in 2004 to only 499 traps in 2006, a decrease of 974%, a phenomenon attributed to the receding water levels which have left the shallow vegetated areas dry. A total of 17,475 fishing crafts, 72% of all fishing crafts, in the Ugandan part of the lake are still using paddles and the. number of parachute crafts is also still very high, (Le. 5,064) comprising a high proportion (21 %) of the total number of fishing. There is need to promote the use of large fishing crafts with sails or a combination of sail and outboard motor. The Mukene fishery in the Ugandan waters of Lake Victoria has remained underdeveloped with only 9% of all fishing crafts operating in this fishery. Also less than 2% of fishing crafts with sails or motor operate in this fishery which implies that it is limited to near shore waters. Effort should be made to develop this fishery as it appears to have high potential, especially in deep offshore waters which are hardly fished.

安徽麝线粒体DNA细胞色素b基因全长序列分析

对安徽麝模式皮张标本进行了线粒体DNA细胞色素b基因全长序列分析。研究结果表明,安徽麝同麝属中其他种的遗传分化已经相当明显。分子系统学的分析表明,安徽麝是一个单系群,它同麝属其他种的DNA序列差异已达到种间分化的程度。因此,线粒体DNA序列的证据支持将安徽麝列为麝属中一有效种(Moschus anhuiensis),而不是前人认为的原麝或林麝的亚种。

Monoculture of climbing perch, Thai koi, Anabas testudineus (Bloch) under different stocking densities at on-farm

An on-farm trial was undertaken in nine earthen ponds (400 to 640m2) to evaluate the growth and production potentials of climbing perch, Thai koi (Anabas testudineus) for the period of four months from March through June 2006. Three stocking densities such as 75,000 (T1), 100,500 (T2) and 125,000/ha (T3) were tested with three replications. Fish were fed with commercial (SABINCO) pelleted feed (35% crude protein). Fish productions obtained in three treatments such as T1, T2 and T3 were 6,480±217, 6,384±154, 6,617±187 kg· 1ha, respectively. The results demonstrated higher mean growth in T1 than in T2 and T3. However, the net benefit was achieved Tk. 7,26,975 from T1, where the stocking density was 75,000/ha.