Technological change in the UK herring industry took place rapidly after 1965, due in part to the active encouragement encouragement given to fishermen to switch from driftnetting to pelagic trawling and purse-seining. The adoption and diffusion of these modern methods of capture stimulated a major expansion of output, but this very success was undermined by the depletion of the fish-stocks on which the industry depended. In the case of the West of Scotland herring fisheries, which were especially important to UK fishermen, the decline in fish-stock biomass caused vessel catch-rates to fall after 1973. The failure of international fisheries management, which acted as a permissive factor in the intensification of fishing effort, also had important economic implications as it resulted in the dissipation of resource-rent. The Authors calculate that the maximum sustainable ‘rent’ which could have been generated from the West of Scotland herring fishery was approximately £14 millions per annum at 1976-equivalent prices. The resource-rent effectively financed the overcapitalization of the fleet and the decline which followed, and it is the speed with which this occurred that most distinguishes the herring fishery from others where technological change has taken place. The article concludes by arguing that, although the UK public authorities (notably the Herring Industry Board) might reasonably be criticized for pursuing a development strategy which resulted in economic and biological over-fishing, the international regime of fisheries management which prevailed at the time gave them little choice but to adopt a pro-active approach to technical innovation.