Trophic Overlap Among Juveniles of Two Targeted Fishery Species and a Non Targeted Fish Species Cohabiting a Large Estuary in South America

GABRIELA ELIZABETH BLASINA; JUAN MANUEL MOLINA; ANDREA LOPEZ CAZORLA

Tampa Bay

Congreso; 147th Annual Meeting of the American Fisheries Society; 2017

AFS

Estuaries serve as feeding grounds and nurseries for several commercially important fish species, where adult populations contribute recruits that take advantage of the estuarine environment to grow properly. Interspecific interactions in early life stages can affect the long-term viability of fisheries stocks, especially considering that this is the most vulnerable stage of development. An understanding of the trophic dynamics and interactions is vital for an effective fisheries management. We determined the trophic overlap among three fish species cohabiting Bahía Blanca estuary, Argentina: two main fishable species, Micropogonias furnieri and Cynoscion guatucupa, and a non targeted species, Ramnogaster arcuata. Overall results from gut content analysis showed varying degrees of overlap, implying shared food resources; high degree of similarity was observed in August for all species, probably due to the high abundance of Acartia tonsa. Despite the temporal variation in dietary overlap, a high degree of overlap was observed between M. furnieri and R. arcuata. C. guatucupa presented the highest dietary segregation. Our results suggest that the recruitment of M. furnieri might be affected by the abundance of R. arcuata in Bahia Blanca estuary, emphasizing the importance of communitywide trophic information, particularly for designing ecosystem-based management plans.