Physiological Effects on Coho Salmon and Steelhead of Exposure to Suspended Solids

Abstract

Yearling coho salmon Oncorhynchus kisutch and steelhead Salmo gairdneri were exposed to high (2–3 g/L) or low (0.4–0.6 g/L) concentrations of three kinds of suspended solids (topsoil, kaolin clay, and volcanic ash) as long as 7–8 d. Such exposure did not cause mortality, but plasma cortisol concentrations were temporarily elevated in both species after exposure to 2–3 g/L of suspended topsoil, indicating that such exposure may have been stressful to the fish. Feeding rates of both species were reduced at high exposure concentrations. Exposure of yearling steelhead for 2 d to high or low concentrations of suspended topsoil, kaolin clay, or volcanic ash induced similar elevations of plasma cortisol levels, and, in groups exposed to high concentrations, blood hematocrits were increased. Osmoregulatory performance in fresh water and after transfer to 26‰ seawater was unaffected, and gill tissue appeared normal, after exposure to suspended solids. Exposure of yearling steelhead to high concentrations of suspended topsoil reduced the fishesˈ tolerance of subsequent infection by the bacterial pathogen Vibrio anguillarum. These results suggest that coho salmon and steelhead can survive exposure to high concentrations of suspended solids, but may undergo sublethal physiological stress that reduces their performance capacity.

Pathology of finfish and mud crabs Scylla serrata during a mortality event associated with a harbour development project in Port Curtis, Australia

“…E denotes exocuticle. H&E. Scale bar = 100 µm tremes, exposure to sediment (Redding et al 1987, Mondon et al 2001, Reid et al 2003, and a wide range of pollutants, including heavy metals and ammonia (Noga 2000), may have a direct toxic effect to the integument. The statistical association of skin disease with ecto-parasitism in our study suggests that parasitic infection was an exacerbating factor in the pathogenesis of skin lesions for some of the finfish species examined in this study.…”

Fish Welfare in Aquaponic Systems: Its Relation to Water Quality with an Emphasis on Feed and Faeces—A Review

“…The studies conducted, mainly on salmonids, highlight the negative effects produced by elevated levels of suspended solids on fish health, consisting of gill abrasion, decreased feeding, increased susceptibility to diseases and increased mortality [95][96][97][98][99][100][101]. Consequently, the acute exposure of salmonids to high concentrations of suspended solids subjects the fish to mechanical abrasion and clogging or coating of the gills, resulting in coughing, respiratory stress and mortality [97,98,102,103].…”

Interactions of Microplastics with Freshwater Biota

“…High concentrations of SPM can accumulate in the gills, disturb the respiratory function, and have been found to translocate into epithelial cells, cause lipid peroxidation, and reduce the tolerance of infection by pathogens [67,68]. Additionally, studies with gill epithelial cells (rainbow trout, RTgill-W1) and fluvial fine sediment revealed translocation of fine minerals (<2 μm, 10-250 mg L À1 ) into the cells as well as material-related cytotoxicity [69].…”