Biology, ecology and behavior of the acoupa weakfish Cynoscion acoupa (Lacepède, 1801) according to the local knowledge of fishermen in the northern coast of Brazil

Abstract

Local ecological knowledge (LEK) of fishers and other actors involved in the fishery can be provide information on the life cycle of fish species they harvest, help defining low-cost sampling projects, new biological hypotheses, management activities and policy measures. This study focuses on fishers’ LEK on diet, feeding, spawning grounds, reproductive size, exploited sizes and perceived changes in abundance over the years of the acoupa weakfish (Cynoscion acoupa), a commercially important marine species. Results from interviews with 240 actors (fishers, captains and boat owners) involved in C. acoupa fisheries in eight municipalities in the northern coast of Brazil indicated that: (a) C. acoupa feeds in areas with rocky bottoms down to the depth of 30 m, eating mainly fish, particularly another weakfish (Macrodon ancylodon) and sardines (Engraulidae); (b) this fish spawns in rocky and non-estuarine habitats; (c) the spawning period mentioned by fishers coincided with the harvest period, but was in disagreement with published scientific information; (d) the median minimum length of individuals of C. acoupa carrying eggs according to interviews was of 70 cm, which was smaller than the length reported in biological studies, possible due to the selectiveness of fishing; (e) there is an overall perception of a decrease in the abundance of C. acoupa among the interviewed fishers, which is compatible with studies on stock exploitation of this species. The current dearth of financial and human resources available for scientific research underlines the importance of making use of LEK to improve fishery policy and management.