This thesis focusses on the integration of economics and ecology in the mathematical modelling of marine ecosystems. The project addressed two aspects of the problem, 1) the relationship between fish price and landings, and 2) the formulation and solving a mean field game model for fisheries. Regarding price flexibility, we performed statistical analysis on ex-vessel fish prices, landings, and other market variables for the whole UK market, and estimated negative own-price flexibilities for numerous individual fish species, and for some broadly defined guilds of species. These provided relationships between the quantity landed and the price received, which generates a feedback between the marine ecosystem and human activity. Regarding mean field games, we developed a model which considers an economic game with a large number of players exploiting a common resource, whose payoffs depend on the collective the actions of all other players. The application of mean field game approaches to a common resource situation was novel and absent in the literature. Solving the mean field game model numerically, we were able to dynamically simulate the feedback between the marine ecosystem and fishing activity. This allowed us to investigate how the dynamics of the coupled economic-ecological system depended on ecological and economic factors, including the price flexibility identified earlier. We found interesting results relating to the impact of price flexibility and its interaction with stock growth rate, showing that higher price flexibilities resulted in increased fishing pressure for stocks with lower growth rates, but decreased fishing pressure for stocks with very high growth rates. Finally, we modelled the implementation of regulations in the mean field game, and demonstrated how these regulations affect the distribution of fishing activity in a mean field game model for a North Sea cod fishery.
| Date of Award | 29 Oct 2021 |
|---|
| Original language | English |
|---|
| Awarding Institution | - University Of Strathclyde
|
|---|
| Sponsors | University of Strathclyde |
|---|
| Supervisor | Mike Heath (Supervisor) & Michael Grinfeld (Supervisor) |
|---|