Port level fishing dynamics: Assessing changes in the distribution of fishing activity over time

• Overall fishing activity declined in the study region over time.
• Relative ranking of ports in terms of level and share of activity was stable over time.
• Ports exhibited significantly different trends in activity over time.

This article assesses changes in the relative distribution of commercial fishing activity within a system of ports. Like other coastal fisheries in the United States, fishing activity declined significantly at California׳s central and north coast region ports between 1981 and 2007. The central questions addressed in this paper are: how have the changes in overall fishing activity (as measured by total regional fishing trips, revenues, and landings) affected fishing activity in each of the central and northern California coastal region׳s 30 fishing ports? How have individual ports fared relative to other ports and the region as a whole during this decline? The analysis assesses the degree to which the relative distribution of fishing activity across ports-as measured by port rankings-is stable over time. The formal rank correlation analysis shows that ports׳ rankings have changed slowly and have changed more over longer intervals. In addition, the rankings change less (more) when the comparison is made over a larger (smaller) set of ports. Tests for the statistical significance of differences in percentage changes in fishing activity between region-wide totals and individual ports are performed. The results indicate that ports differ in terms of their dynamic fishing activity patterns over time, which constitutes a rejection of the null hypothesis that the cumulative percent changes at individual ports are the same as changes at the region-wide level.