A BAYESIAN COMPARISON OF TWO HELMINTHES POPULATION IN JUVENILES OF MUGIL LIZA FROM SAMBOROMBON BAY, ARGENTINA.

MONTES M MARTIN; MARCOTEGUI, PAULA S; MARTORELLI SERGIO R

VIÑAS DEL MAR

Simposio; VIII INTERNATIONAL SYMPOSIUM FISH PARASITOLOGY; 2011

UNIVERSIDAD DE ANTOFAGASTA

The main objective of this presentation is to compare the helminths population in juveniles Mugil LIza from Samborombon Bay mainly with Bayesian statistics. Samples were collected at two sites, one in the North, in the relief Channel of Salado River (Site 1), and the other in the south in the Ajo River (Site 2). A total of 65 juveniles of M. liza from Site 1 and 93 from Site 2 were captured. Fishes were weighted, measured and revised for helminths. The prevalence and intensity was calculated for  Digenea, Monogenea and Acantocephala. Nematoda was not considered in this study due to its low prevalence. The Bayesian tests were made using WingBUGS free software. The digenean species was Dicrogaster fastigata, Hymenocotta manteri, and the metacercarie Ascocotyle (Phagicola)  sp. This is the first record in Argentina for H. manteri. The Monogenean was Ligophorus saladensis, Metamicrocotyle macracantha and Microcotyle pseudomugilis. Only one species of Acantocephala, Floridosentis mugilis, was collected. We found a high prevalence and intensity of Digenean in Site 2, a high prevalence of Monogenean, but the intensity was lower compared with Site 1 (p>0,05). The Acanthocephalan had the same prevalence in both sites, but the intensity was high in Site 1 (p>0,05). Those differences might be due a Phosphorus and Nitrogen gradient from north to south of the Bay and a different type of contamination in the water of Site 1 (As, Cr, Cu, Pb, Zn) and in the sediments of Site 2 (Pb y Hg). Besides a greater marine influence at site 2 may have contributed to the observed  differences  in both sampling sites.