老桥狂钓流水鱼

日落西山，虽意犹未尽，但我和老王早已累得筋疲力尽，无意再战。而杜钓友年富力强，仍面无疲倦之色。他把我和老王的水留下来，心意坚决地要独自夜钓，他的口号是“今朝有鱼今朝钓，过了此村再无店”。

理鱼输送作业流水线

我们鱼品加工厂进厂的原料是“鱼鲜”，其特点是：鱼汛时，鱼货集中，时间紧迫，规格混杂，质量受气温、环境、时间的影响极大。鱼汛时平均每天理鱼进冻达18吨，必须逐筐去冰，逐条分类、拣鱼、装盘、过磅以及进库速冻，过去全靠手工操作，劳动强度很大。

Analysis on Growth of Released Black Carp and Annual Benefits from Released Fish in Yantan Reservoir

The research explored growth and development, economic profits, and eco- logical benefits of released black carps on basis of 21 group ecological data on 52 365 fish within 6 months. The results indicated that the age and growth index of released black carp were normal and body length and size were coordinated; 88.89% released black carps exceeded theoretical weight, with an average of 25.15%, which indicated that black carps are hardly to reproduct naturally. In 2013, 310 000 black carps were released in the Reservoir, and 123 tons black carps were obtained, with direct economic value of 2.46 million yuan and indirect econom- ic value of 3.84 million yuan. It can be concluded based on averages that 123 tons black carps can be produced in 2013 and 3 690 kg nitrogen and 740 kg phospho- rus can be removed. The releasing of fish has shown much more economic, ecological and social benefits in Yantan Reservoir, but the hidden dangers still exist on fishery environment. Therefore, it is necessary to further increase the number of re- leased black carps in the Reservoir.

Influence of a large dam on the longitudinal patterns of fish assem- blages in Qingyi Stream

Using seasonally collected data(2009-2010) from 15 sampling sites that represent first- to fifth-order streams within the Qingyi watershed,we examined the spatio-temporal patterns of fish assemblages along two longitudinal gradients to explore the effects of a large dam on fish assemblages at the watershed scale.No significant variation was observed in either species richness or assemblage structure across seasons.Species richness significantly varied according to stream order and gradient.Dam construction appeared to decrease species richness upstream substantially,while a significant decrease between gradients only occurred within fourth-order streams.Along the gradient without the large dam,fish assemblage structures presented distinct separation between two neighboring stream orders,with the exception of fourth-order versus fifth-order streams.However,the gradient disrupted by a large dam displayed the opposite pattern in the spatial variation of fish assemblages related with stream orders.Significant between-gradient differences in fish assemblage structures were only observed within fourth-order streams.Species distributions were determined by local habitat environmental factors,including elevation,substrate,water depth,current discharge,wetted width,and conductivity.Our results suggested that dam construction might alter the longitudinal pattern in fish species richness and assemblage structure in Qingyi Stream,despite the localized nature of the ecological effect of dams.

Computational Study on Interaction Between Swimming Fish and Drifting Vortices Behind the Cylinder

To predict the flow evolution of fish swimming problems,a flow solver based on the immersed boundary lattice Boltzmann method is developed.A flexible iterative algorithm based on the framework of implicit boundary force correction is used to save the computational cost and memory,and the momentum forcing is described by a simple direct force formula without complicated integral calculation when the velocity correction at the boundary node is determined.With the presented flow solver,the hydrodynamic interaction between the fish-induced dynamic stall vortices and the incoming vortices in unsteady flow is analyzed.Numerical simulation results unveil the mechanism of fish exploiting vortices to enhance their own hydrodynamic performances.The superior swimming performances originate from the relative movement between the“merged vortex”and the locomotion of the fishtail,which is controlled by the phase difference.Formation conditions of the“merged vortex”become the key factor for fish to exploit vortices to improve their swimming performance.We further discuss the effect of the principal components of locomotion.From the results,we conclude that lateral translation plays a crucial role in propulsion while body undulation in tandem with rotation and head motion reduce the locomotor cost.

Seasonal shifts in the solute ion ratios of vadose zone rock moisture from the Eel River Critical Zone Observatory

One of the greatest challenges in critical zone studies is to document the moisture dynamics, water flux,and solute chemistry of the unsaturated, fractured and weathered bedrock that lies between the soil and groundwater table. The central impediment to quantifying this component of the subsurface is the difficulty associated with direct observations. Here, we report solute chemistry as a function of depth collected over a full year across the shale-derived vadose zone of the Eel River Critical Zone Observatory using a set of novel sub-horizontal wellbores,referred to as the vadose zone monitoring system. The results of this first geochemical glimpse into the deep vadose zone indicate a dynamic temporal and depth-resolved structure. Major cation concentrations reflect seasonal changes in precipitation and water saturation, and normalized ratios span the full range of values reported for the world's largest rivers.

Anisakid Nematodes of Pagellus acarne and Trachurus trachurus, from North Atlantic Moroccan＇s Waters

An epidemiological survey of anisakid nematodes was conducted on 205 specimens of horse mackerel （Trachurus trachurus） and 183 of axillary seabream （Pagellus acarne） captured in the zone between Tangier and Larache in the north Atlantic Moroccan＇s coasts. Three species of nematodes were morphologically identified： Anisakis simplex s.l., Hysterothylacium sp., Pseudotarranova sp. According to the season, the nematode most observed in T. trachurus was .4. simplex s.1. （the highest values of prevalence （100%）, the mean intensity （48.6）. Hysterothylacium sp. was the most frequent anisakid in P. acarne with 100% of prevalence and 34.46 of the mean intensity. The infestation parameters were also analyzed according to the host species length, noting a maximum of infected fish by Anisakis simplex s.1. （96%） in samples of horse mackerel larger than 28 cm, while in axiliary seabream, the highest prevalence of infestation by Hysterothylacium sp. （100%） was found in fish more than 29 cm.

A survey on fabrication,control,and hydrodynamic function of biomimetic robotic fish

Understanding and replicating the locomotion principles offish are fundamental in the development of artificial fishlike robotic systems,termed robotic fish.This paper has two objectives:(1) to review biological clues on biomechanics and hydrodynamic flow control offish swimming and(2) to summarize design and control methods for efficient and stable swimming in robotic fishes.Our review of state-of-the-art research and future-oriented new directions indicates that fish-inspired biology and engineering interact in mutually beneficial ways.This strong interaction offers an important insight into the design and control of novel fish-inspired robots that addresses the challenge of environmental uncertainty and competing objectives;in addition,it also facilitates refinement of biological knowledge and robotic strategies for effective and efficient swimming.