Fish Community Structure And Correlation To Major Environmental Factors In Zhenjiang Section Of The Yangtze River

This study describes and gives an overview of the current status of the fish community struc ture and correlation to major environmental factors in the Zhenjiang sector of the Yangtze River.Fish community is the part of fisheries science that studies the status of a fish stock and the com munity that considerably engages in the harvesting or processing of fishery resources to meet the needs of the fishing vessels owners,operators,and fish processors that are dwell in such commu nity.Fish constitutes a major foundation of animal protein in most part of the world.Fish has the most balanced protein and amino acid profile making its consumption widespread across all relig ious and cultural obstructions therefore,fish is very high in demand(Fasakin,2008;Adewunmi a nd Fagbenro,2009).The instant growth of aquaculture has highlighted many challenges to sustai nable development as it relates to environmental factors in the fish community.According to this work various indexes used in this survey are:Shannon-Weiner diversity index,Margalef richnes s index,and Pielou evenness index.Aquaculture initiatives often suffer low production efficiency,due to bad environmental pra ctices.In spite of the enormous importance and value of the fisheries and aquaculture sectors in t he world,fishery resources are distress from the combined effects of heavy exploitation such as:overfishing,illegal sand digging,pollution,the use of harmful fishing gears and,in some cases,e nvironmental degradation as in the case of the Zhenjiang section of the Yangtze River.There are many reasons for this undesirable state of concerns,but the principal reasons for these behaviors come down to the failure of fisheries authority in many countries to effectively control the fisher y community and its resources.Degenerations of aquatic biodiversity threaten negative impact o n the health and livelihoods of millions of people around the world who depend on ecosystem ser vices provided by aquatic resources and the Zhenjiang section of the Yangtze River is of no excu se.The concern of fishery explorations and pollution of aquatic environment is a universal conce rn which needs handling with concern.In the past many years;China has advanced to be one of t he most important countries of fishery production.On a yearly situation the Chinese fishery prod ucts are growing.But there are serious problems behind the encouraging surface(China statistica 1 reports.2009).China’s fishing industry,however,has increasingly become the casualty of its o wn success.This thesis also outlines some physical and chemical parameters that were tested dur ing the water quality test in the Zhenjiang section of the Yangtze RiverEnvironmental factors are several factors that influence living organisms and their communi ty.Several factors are visible,while others cannot be seen.Environmental factors may affect livi ng things either directly or indirectly.Both factors may act equally in structuring fish populations and communities.Organisms respond to factors in the environment in which they live.Environ mental factors are group into two major parts,abiotic(nonliving)and biotic(living).Both abiotic and biotic factors function to maintain a continuous energy flow and nutrient cycling.Some exa mples of abiotic factor and their effect on the environment and species are:1:Temperature,temp erature is an indication of the amount of heat energy in the environment;the higher the heat cont ent,the higher the temperature.On a worldwide basis,temperature is perhaps the overriding fact or affecting species distribution.It is one of the most serious factors of the environment and exert s a deep influence on all physiological activities of species in the environment by controlling the rate of chemical reaction.According to the data in this work index of relative importance(IRI)"was used to describe the community dominance.Species with an IRI index greater than 100 were identified as common species.Species greater than 1000 were designated as dominant speciesThe temperature at which organisms can occur is called the physiological range.It changes i n different organisms depending on local adaptations.A temperature of 52℃ is about as high as any animal and protozoan can still grow and replicate.2:Oxygen,oxygen is a clear,colorless,od orless,and tasteless gas that dissolves in water.It is supplied by diffusion of atmospheric(air)ox ygen into the water and by making of oxygen from photosynthesis by aquatic plants.Both plants and animals depend on dissolved oxygen for survival.Lack of dissolved oxygen can cause aquati c animals(e.g.fish,macro invertebrates)to quickly escape the environment or face death.And th e list goes on for abiotic factors in the fish community.In every environment,fish have evolved co mbinations of physiological,morphological and biomechanical traits which adjust them to their particul ar habitat.In particular,almost all fish swim.The critical swimming velocity of fish is affected by e nvironmental conditions and the highest swimming speed is obtained only under specific circums tances.The mechanisms causing a reduction in exercise capacity depend on the type of environm ental change.Based on the investigation data,four main fish fauna group turned up in Zhenjiang section of the Yangtze River and they are:Complex of China plain faunal,Complex of late tertia ry early fauna,South Yellow Sea,east China Sea offshore group and Complex of China plain fau nal.Acid waters apply an effect by reducing oxygen transport capacity,whereas reduced tempera tures act largely on muscle contractility.Examples of biotic factors and their effect on the environment are:1:Human activities are adversely impacting on most of the environmental factors.Humans,through uncontrolled exploit ation of living resources,are depleting those resources faster than nature can replace them and ar e already threatening the continued existence of the resources in the environment.Example:the d igging of sand from the water destroys the home of the fish and cost scarcity of spawning sites.Under these circumstance,there is no doubt to make an investigation on the traits of the fish com munity,such as the species composition,community diversity of fishes,fish food chain,the wate r quality,dominant species in the fish community and other environmental factors that constitute s the entire fish community.This research further elaborate on the biological characteristics of tw o ecotype species in the Zhenjiang section of the Yangtze River namely the bream and the coilia ectenes.Such biological characteristics are:age structure,growth characteristic,determining the sex ratio,and distribution of standard body length and body weight.It is very important to study and investigate the biological species of fish and other aquatic organisms in the fish community.Such understanding is largely the foundation for fishery guideline.It helps in determining th e basic to improve a given environment.Scientific understanding for the improvement of fishing activities lies in a close knowledge of the biology of fishes.Without appropriate knowledge of th e life,habits and behavior of fishes,it is not possible to plan,control and manage the fish species and other aquatic resources in an adequate manner.In this explanation,the importance of biolog ical studies in the development of fish species is very important.To conclude fishery investigatio n is a very strategic area to note,reason been it allows fishery authority to understand the status of the fish community and the species within said community and proffer a good solution to that effect.This work also stresses the importance of the fish for chain examples:phytoplankton,zoo plankton and etc.