Ocorrência de parasitos em peixes de água doce em Laranjal do Jari-ap

Abstract

The Amazon basin represents the greatest freshwater fish diversity in the world, contributing with numerous species of fish of different taxonomic classifications. In Laranjal do Jari-AP, scientific research related to ichthyofauna, especially in the area of parasitic ecology, is scarce. The Jari River is the most important water body in the Jari Valley region. Human activities on the banks of the river can alter the essential conditions of this aquatic ecosystem and this change can directly affect population dynamics. This study sought to characterize the parasitic fauna, quantifying, calculating the indices and preparing a parasitological booklet for fish from the Jari River. 46 specimens belonging to 13 fish taxa were collected between the months of February and October 2023. Leporinus spp. presented length (cm) and weight (g) of 20.3 ± 4.5 cm and 120.3 ± 67.1 g, Mylossoma spp. 17.1 ± 0.8 cm and 106.2 ± 6.05 g, Pygocentrus spp. 22.7 ± 3.2 cm and 295.5 ± 94.9 g, Hemiodus spp. 17.5 ± 5.2 cm and 65.5 ± 52.3 g, Platydoras spp. 15.0 ± 1.4 cm and 55.2 ± 26.7 g, Geophagus spp. 16.0 ± 1.0 cm and 71 ± 6.5 g, Rhaphiodon sp. 37 cm and 286 g, Acestrorhynchus sp. 32 cm and 235 g, Ageneiosus sp. 23 cm and 134 g, Triportheus sp. 20 cm and 110 g, Brycon sp. 32 cm and 520 g, Pimelodus sp. 16.7 cm and 41 g, and Rhamdia sp. 18 cm and 70 g. The diversity of fish follows Amazonian standards. Four groups of parasites were found (Capillaria, Nematoda, Isopoda and Acanthocephala) belonging to 3 taxa. The Capillaria group stands out with the highest number of parasites. There was variation in the number of parasites during seasonal periods of flood and drought. However, the infection rate remained balanced between periods, with 6 infected fish for every 10. The length and weight of the fish did not show any correlation with any parasites found. New complementary studies on the parasitic ecology of fish in this environment are essential to obtain a more complete overview of the characterization of the parasitic fauna.