LONG-TERM CHANGES IN PARASITE COMMUNITIES OF AN INTENSELY EXPLOITED COASTAL FISH: EVIDENCE OF OVERFISHING?

A.L. LANFRANCHI; CANEL D.; ALARCOS A.J.; BRAICOVICH P. E.; TIMI J.T.

Congreso; 15th International Congress of Parasitology (ICOPA 2022); 2022

World Federation of Parasitologists

Introduction: Cynoscion guatucupa is one of the main resources of coastal fisheries in Argentina. During the last decades, changes in its abundance and population structure have been detected, due mostly to fishery pressures. Indeed, fishery reduces fish density and the complexity of food webs, having a correlate on the parasite assemblages they harbor. Aim: to assess if the composition and structure of parasite assemblages have changed in different cohorts along the last three decades.Methods: 80 fish caught at different latitudes in the Argentine Sea in 2018 and 2019 (3 samples, TL: 30, 35 and 45 cm, respectively) were examined, and the structure and composition of their parasite infracommunities were compared with those of 197 fish from the same regions caught in 1993-1994 (5 samples) by multivariate methods.Results: 19 parasitic taxa were found and 9 long-lived parasites were selected for analyses. Infracommunity diversity did not vary across samples, although their structure and composition were significantly different between periods, but not between samples of the same period. That result was related to an increase of abundance for some species and to a decrease of others. Changes were observed also for some adult parasites, specific of this host.Conclusions: It is difficult to identify the causes of the observed changes, especially because this fish is targeted in a multispecific fishery that affects the entire community. Most of the changes seems related to species having elesmobranchs as definitive hosts. Intermediate dates should be necessary to asses if changes are unidirectional or not, however the value of parasites to monitor temporal variability of exploited populations is confirmed.