Well-defined and enforceable property rights are usually seen as a prerequisite
for optimal resource management. However, the interaction effects between
different renewable resource pools with different ownership structures are often
not well recognized. In this paper we introduce these interaction effects in
optimal fishery management theory. Various property rights regimes and market
structures for fisheries are analyzed. Furthermore, we perform a sensitivity
analysis with respect to the carrying capacity of a fish lake for the different
agents. We describe various approach paths towards the new equilibrium after
opening up to a common market. We show that a decline in market power leads to a
lower stock and a higher supply. Furthermore we identify conditions under which
market power might reduce profits.