For more than 100 years efforts have been made to increase the abundance of the various species of Pacific salmon. The success of these ventures is largely a matter of conjecture because the scale of natural fluctuations is sufficient to mask the effect of human intervention. No well-defined program for salmon enhancement has yet been developed for British Columbia as a whole. This is mainly attributable to the pressures for providing protection for the existing stocks in the circumstances of an intensive fishery and increasing effects of other resource uses.From a social point of view, salmon enhancement is a highly desirable activity. Salmon occupy a special place in the culture of residents of the Pacific coast. Salmon arc economically valuable and salmon fishing provides a rich source of employment. Recreational fisheries are valuable but their true economic worth is difficult to judge. Benefit:cost ratios for salmon enhancement should be calculated for whole programs rather than for individual projects to obtain an approach consistent with the desirable strategy of development.From a biological point of view, salmon enhancement is feasible. There is potential in the ocean for growing more salmon; many historic runs can be rebuilt and there are many opportunities for colonizing watersheds that are currently inaccessible to salmon. Harvesting of increased stocks of salmon could pose risks for natural stocks that are relatively unproductive. More effective management and development of new strains of salmon may be required in these circumstances. Predator-control programs may in some instances be useful adjuncts to salmon-enhancement projects.The types of enhancement activity that will most likely be rewarding are those that interfere least with the natural life history. Removal of obstructions, regulation of stream flow, construction of artificial spawning channels, are typical simple measures that involve less research information and less risk than rearing hatcheries.Priorities for different salmon-enhancement projects involve consideration of the regional economic and social conditions as well as appreciation of the biological and physical problems. Regardless of priorities it is essential to a successful program that there be a commitment to continuity. Additionally, the total administrative complex for salmon enhancement should involve research components.The execution of a successful salmon-enhancement program depends on the establishment of an agency with the single responsibility of salmon enhancement. The financing of a successful program should depend partly on revenues generated from the resource users, such as a tax on commercially caught salmon, a license for saltwater angling. Special grants from federal and provincial governments would also be appropriate. Regardless of the administrative arrangements, it is urgently necessary that provincial government involvement be more substantial than it is at present. With their control over resource management practices, the provincial government is in a vital position for maintenance of freshwater environments.An investment of at least $100 million, and probably twice that amount, could be undertaken in a salmon-enhancement program that could be executed within 10 years. There are compelling reasons for starting on this enhancement program immediately.
Methodological aspects of the stock-recruitment curve analysis
