What can be learned from fishers? An integrated survey of fishers' local ecological knowledge and bluefish (Pomatomus saltatrix) biology on the Brazilian coast

Bluefish (Pomatomus saltatrix) has a worldwide distribution, being targeted by fishers all along its range, which includes the Brazilian coast. We formulated and checked hypotheses regarding bluefish diet, migration, and reproduction based on fishers' local ecological knowledge (LEK). We interviewed 49 experienced fishers (40 years and older) from five communities along the Brazilian coast and analyzed the diet and reproduction of 185 fish. According to fishers' LEK, the bluefish spawn mainly during the winter, migrate throughout year (from the South to North), and eat mainly small fish (Clupeidae and Engraulidae), plus shrimp and squid. The biological survey confirmed the hypothesis on bluefish diet (78% of fish with stomach contents had fish in their stomachs) but not that on reproduction: we observed larger fish and more fish with visible eggs during summer and autumn. Migratory movements mentioned by fishers agreed with literature data. Besides providing data to support conventional management decisions in the absence of biological surveys, our results and approach could help involve fishers in management, thus contributing to development of co-management systems more suitable to local conditions and to complex tropical fisheries.