Gordon Theory, Open Fisheries Ecosystems

In the real world, economic factors affect the harvest and development of fishery resource. Hence, the study of the question is significant in ecology and economics. In this paper, research of open- access fishery is the base. By definition, an open-access resource is one in which exploitation is completely uncontrolled, Anyone can harvest the resource. For example :high seas . By the restriction of economic interests, we only demand the economic rent, which leads to zero rent eventually. In 1954 , the economic theory of the open-access fishery was developed dy H.S.Gordon, and the classical the economic equilibrium conditions of Gordon theory were builded.In[16],opportunity cost is considered and Gordon theory is further modified.The primary study is in this paper as follows:1.By document[16],the classical Gordon theory is further modified from changeable price and variable cost , and the common results are obtained.2.The Gordon theory of n-population Lotka-Volterra ecological system with constant coefficients is considered, the economic equilibrium conditions of the corresponding system ,and the stability of economic equilibrium of system are discussed . By taxing about some over-exploitation populations how to restore optimal population level is moderately studied. The classical Gordon theory is improved from opportunity cost.3.In the paper, we consider Gordon theory of a class of single-species ecological systems with periodic coefficients on open-access fishery, and set up the ordinary economic equilibrium conditions of the single-species and get globally asymptotically stable economic equilibrium ;the over-exploitation of the system and the modification on economic equilibrium conditions by opportunity cost are investigated. Our results include almost all nonautonomous single-specie harvesting models with periodic coefficients; for example: Logistic model, Gompertz model. Gilpin model. Aynala model.