| Lake Changhu as an important part of the third largest lake and Four Lakes Jianghan Plain in Hubei Province, not only has the regulation and storage, irrigation, water supply, tourism, fisheries, navigation and other functions, but also to maintain the Jianghan Plain and the ecological balance of the middle reaches of the Yangtze River important wetland ecosystems. Lake Gangcha large, lush plants, fish, shrimp, shellfish resources very rich. But in recent years, with the improvement of people’s living standards, human overfishing is serious, factors fence / fence farming, waste water as a result of increased water pollution, resulting in the loss of aquatic resources in recent years, the lake is more serious. Coilia brachygnathus is a small fish economy Lake Changhu, both with small fish, shrimp for food, but also as a large predatory fish bait and porpoises, plays an important role in the food chain, on Lake Changhu Coilia brachygnathus no related studies, making it necessary to carry out systematic research. This paper studies the aspects of Lake Changhu Coilia brachygnathus age and growth, reproductive strategy, population dynamics and assess the genetic diversity of the Yangtze River and other geographical groups. Thesis results are as follows:1.Age and Growth: scales and otoliths can be used to identify the Coilia brachygnathus age rings distinctive characteristics. Identification of the goodness of fit between the two age reached 75.8%. In comparison, the otolith is the most suitable material for age determination of anchovy short jaw. Lake Changhu Coilia brachygnathus population body length range 102.00-326.00 mm, weight range 3.36-120.10 g. Focus on its strengths length 131-246 mm, accounting for 89.77 percent of the total population. Advantages weight range 3.36-32.55 g, accounting for 88.94 percent of the total population. Coilia brachygnathus body length and weight of the power function relationship, the relationship of the formula: W = 6.29* 10-6L2.855(n = 479, R2 = 0.959, P <0.01). Von Bertalanffy growth equation is: Lt = 332.86 [1-e-0.213(t + 1.775)], Wt = 99.940 [1-e-0.213(t + 1.775)] 2.855. 3.15 inflection age of age.2. Reproductive strategy: Lake Changhu Coilia brachygnathus population sex ratio was 1.29: 1. Minimum sexually mature individual, body length 126 mm, weighing 6.66 g, age 1 age. Statistics 15 Ⅳ of female fecundity, and its body length in the range of 126-226 mm, weight range 6.66-33.82 g. Absolute fecundity of 5761-19766 grains, grains relative fecundity of 428.08-547.22 / g.3. Population dynamics:Lake Changhu Coilia brachygnathus of total mortality(Z) 0.635 / year; the natural state mortality coefficient(M) of 0.457 / year; fishing mortality coefficient state(F) 0.178 / year; Lake Changhu Coilia brachygnathus exploitation rate(E) of 0.552 / year. In the management of ecological resources, Lake Changhu Coilia brachygnathus annual anchovy biomass 2425.5657 kg. Lake Changhu Coilia brachygnathus belong r- select the type of fish life history.4. Genetic diversity: population Lake Changhu, Chaohu groups, group Dongting, Poyang Lake population four geographical populations of Coilia brachygnathus, using in 1236 bp D-loop sequences analyzed a total of 108 variable sites, 54 parsimony informative site. 98 individuals total 66 haplotypes, haplotype diversity and nucleotide diversity index 0.0098 0.981 display four geographical populations have a higher genetic diversity, population size stable. Four geographical populations of short jaw anchovy genetic differentiation index(FST) is 0.23301, showing moderately differentiated level, mainly for the middle level Chaohu differentiation between groups and other groups. Construction of a system based on genetic distance phylogenetic tree results also show similar results, genetic and geographic distances there is a certain correlation. |
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