Fisheries throughout the world have long been subject to overfishing and excess capacity, which has generated substantial and increasing concern about biological and economic performance ramifications. These problems in part stem from substantial investment in technical improvements to boats and equipment in fishing fleets. Such technical change exacerbates the extent of excess fishing capacity, as well as low returns to fishing effort and investment due to catch limitations from both regulatory constraints and overfished stocks. However, economists have not yet attempted to quantify the extent or effects of technical change in fisheries. In this paper we use detailed data on innovation patterns for 19 vessels in the Sete trawl fleet of Southern France to evaluate the contributions of embodied and disembodied technical change to catch rates. We find that embodied technical change enhanced productivity by approximately 1 percent per year between 1985-99, but that external (disembodied) events counteracted this by causing a net output decline of about 3 percent per year. Neither efficiency nor output composition changes appear to have had a substantive effect on observed performance levels.