Shrimp fishing in the Sea of Marmara is a traditional activity that generates direct employment in small-scale fisheries and provides a significant contribution to the regional economy. Despite its long-standing cultural and economic importance, recent structural changes in the marine ecosystem have increasingly threatened the sustainability of this fishery. Therefore, understanding its economic dynamics is crucial for guiding sustainable fisheries management. In this study, one-year accounting records from 19 vessels were analyzed to assess the economic performance of shrimp fishing conducted with the algarna method. The findings revealed that more than 75% of the total fishing income was derived from shrimp sales, while by-products contributed an additional average of 24.4% to revenues. This demonstrates that shrimp remains the primary driver of profitability, although by-catch serves as an important short-term income buffer. Among operational costs, fuel expenses ranged between 32% and 60.4%, with an average share of 46.2%, followed by labor costs varying between 22% and 50.1%. Other expenditures included packaging, refrigeration, provisions, marketing, transportation, and maintenance-repair. During the fishing season, the average daily shrimp catch per vessel was calculated as 98.9 kg, corresponding to an average daily income of 19,288 ₺. The profitability ratio was consistently recorded within the range of 48–50%, indicating that shrimp fishing remains an economically viable and satisfactory livelihood option. These results highlight the importance of balancing economic profitability with ecosystem sustainability to ensure the long-term resilience of shrimp fisheries in the Sea of Marmara.