Artisanal fishing discards as birds' food resource in the southern Brazil

Abstract

Fishing discards have been reported as a source of food for birds, especially in industrial fishing, however little is known if the same occurs with artisanal fishing. In this paper, we test the hypothesis that the discards of artisanal fishing are used by birds as food, including limnic and land species. Between August 2013 and July 2014, 30 observations were made at four observation points, located in southern of Brazil, where the frequency of occurrence, similarity in the use of the resource and the comparison between discards areas were analyzed. A total of 33 bird species and 34 discarded taxa were recorded, with differences between the sampled areas. Four groups of birds were identified: (1) waterbirds that consume food in both environments (seven species); (2) waterbirds that consume food in the aquatic environment (seven species); (3) waterbirds consuming food in the land environment (10 species) and (4) land species (nine species). The aquatic environment had a higher number of discards than the land one. Discards are used by a large number of bird species and their use is determined by the discards area, morphological characteristic and foraging technique of birds. Thus, the study hypothesis was accepted.