Abstract

Analyzing the spatial dimension of global fishing effort provides insights into the mechanisms driving its expansion through time. It also enables confronting the spatio-temporal trends of fishing effort with the well-documented global depletion of major commercial fish stocks. This report presents analyses of the evolution and spatial distribution of port-based global fishing effort from 1970 to 1995, a period of global fisheries expansion. A model involving qualitative filter criteria and quantitative weighting of fishing grounds was developed to predict the spatial distribution of port-based global fishing effort within the EEZs of all maritime countries of the world. These were then grouped into four sets for regional analyses, and pooled for an overall analysis of global trends. The results of these analyses showed that, on a global scale, effective fishing effort grew by 500% in the period between 1970 and 1995. This growth led to reduction of total catch per unit of effort (CPUE) by 70% over the same period. The prediction of spatial distribution of port-based global fishing effort showed that fishing effort covered all continental shelves in the 1990s, with intensely fished areas clustered along the coasts of all major fishing nations. In addition to the offshore range expansion implied here, the results revealed that the centers of fish catch and effort concentrations gradually moved southward by 20o and 10o, respectively. Additionally, the fuel consumption of port-based global fishing fleets was estimated, using an independent estimate of global fisheries fuel consumption. The result gave a fuel consumption rate of 0.1-0.3 liters per horsepower-hour. When this is applied to time-series of global fishing effort, this results in the fuel consumption of global fishing fleet growing by 85 % (2.2% per year) during the period from 1970 to 2000.