Parasitic monogenoideans of Sciades herzbergii as bioindicators of environmental quality in amazonian estuarines ecosystems

Abstract

This study evaluated the use of gill parasitic monogenoideans from Sciades herzbergii (Siluriformes: Ariidae) as bioindicators of environmental quality in Amazonian estuarine ecosystems. Fish were caught in the tidal channels in an impacted area - IA, near the port of São Luís and a reference area - RA, in the Caeté estuary, Bragança. The influence of the capture site and seasonality on parasite abundance, environmental variables and biometric data of hosts were verified. A total of 416 S. herzbergii specimens were analyzed. The weight and total length of fish from the RA were greater than those of the IA. The relative condition factor was influenced by seasonality. A total of 4,265 monogenoidean specimens from the following species were identified: Chauhanellus boegeri, C. susamlimae, C. velum, Calceostomella herzbergii and Dactylogyridae gen. sp. The seasonal mean parasitic abundance of C. susamlimae was significantly different, with the highest values recorded during the dry season. The mean abundance of C. herzbergii was influenced by seasonality and by the capture site. During the rainy period, the parasite indices in the RA were higher than those of IA. C. herzbergii is a bioindicator sensitive to low water quality, especially in relation to water turbidity in Amazon estuaries.

Ecology and effects of metazoan parasites of fish in transitional waters

“…Cunha et al . (2021) confirmed monogeneans as sentinels of water quality, but their research in Amazon estuaries indicated a higher parasite abundance in the impacted area than in the reference area. Urbanization, measured through landscape and physicochemical factors, has been proven to influence parasite communities in the estuarine fish Fundulus heteroclitus , with the most significant effects detected in indirect life-cycle parasites (Alfieri and Anderson, 2019).…”