Comparative feeding analysis between the Chilean eagle ray Myliobatis chilensis (Philippi, 1982) and the Peruvian eagle ray Myliobatis peruvianus (Garman, 1913) from northern Peru

This study analyzed the diets of eagle rays in northern Peru to understand their intraspecific and interspecific feeding patterns, as well as their roles in the marine ecosystem. We obtained 109 stomachs with contents from Chilean eagle ray Myliobatis chilensis and 81 from Peruvian eagle ray Myliobatis peruvianus, between December 2020 and November 2021 in northern Peru (6º47'54"S and 79º59'30"W, San Jose, Lambayeque). The results show that M. chilensis has a benthic-pelagic feeding behavior with 14 prey families identified in its diet. The Peruvian anchovy Engraulis ringens, unidentified polychaetes, and families Onuphidae, Sternaspidae, Opheliidae, among others preys, were identified. On the other hand, M. peruvianus consumed Nassariidae, unidentified mollusks, unidentified polychaetes, and Veneridae, among other preys. We also found that both rays are secondary consumers with a restricted diet breadth (B_i < 0.6), where M. chilensis showed significant differences in diet by season and size class, while M. peruvianus only by size class. This study provides new information about eagle rays and is the first study to compare their diets. Furthermore, it also provides evidence of trophic segregation; however, given some overlap of some prey groups, low ecological redundancy. Finally, this study provides key information for the conservation of eagle rays in an important marine ecosystem in the eastern Pacific Ocean.