This study examined the Current energy balance, energy conversion efficiency, and farm-level efficiency of trout and sea bass production in the Black Sea of Turkey. Using a structured survey, we collected data from nine monoculture trout farms and five polyculture trout and sea bass farms during the 2005-2006 production season. Energy values were calculated using energy equivalents of the inputs and outputs for the farms. Data envelopment analysis was used to calculate farm-level efficiency. The total energy use per cubic meter was 46.57 MJ for trout production and 87.13 MJ for sea bass production. The main energy inputs were feed and diesel oil for both trout and sea bass production. Indirect energy use was dominant in trout production, while direct energy use was more common in sea bass production. The energy input-to-output ratio of trout production was higher than that of sea bass production. Sea bass production was more economically energy efficient compared to trout production. The allocative and economic energy efficiencies for trout and sea bass production were 0.788 and 0.881, respectively. For both types of farms, the most discriminative variable affecting economic efficiency was operator experience. Increasing focus on product distribution costs could decrease total energy costs by approximately 12%. (c) 2008 Elsevier Ltd. All rights reserved.