In other words, stocks of desirable fish tend to end up overfished. All will reduce fishing effort and potentially preserve the stock. Each has subtly different economic effects, however, and some may be politically impossible in a given setting. One of the best is limiting the number of permits, which, while limiting the number of people who can make a living at fishing, theoretically insures that those fishing can make a living. Catch is often lumped by fishers or processors into broad market categories including several species.
Effort includes both gear and time.
Fisheries which involve pelagic schooling fish have both a search component and a fishing component. Employment of spotter planes will shorten the search time but not the fishing time. Obviously commercial records by themselves are inadequate, the fisheries manager must conduct additional surveys, sampling, and perhaps even covert observation to accurately determine both catch and effort. Data from the commercial catch should always be supplemented from fishery-independent data. Complicated statistical analysis is essential.