00000cam 2200000zi 4500 9.956778 CaOODSP 20251119071541 m o d f cr bn||||||||| 251028e198905##nsc ob f000 0 eng d CaOODSP eng rda CaOODSP eng eng fre n-cn-ns x8x8 Fs97-4/2016E-PDF Fs97-4/2016E Farmer, Gilbert J., author. Mortality of juvenile Atlantic salmon (Salmo salar) exposed to water withdrawn from the hypolimnion of a headpond on the Mersey River, Nova Scotia / G.J. Farmer, T.R. Goff and D. Ashfield. Halifax, Nova Scotia : Freshwater and Anadromous Division, Biological Sciences Branch, Department of Fisheries and Oceans, May 1989. ©1989 1 online resource (v, 8 pages). text txt rdacontent computer c rdamedia online resource cr rdacarrier Canadian manuscript report of fisheries and aquatic sciences, 0706-6473 ; no. 2016 Digitized edition from print [produced by Department of Fisheries and Oceans]. Includes bibliographical references (page 6). "A mortality of 8.6% of the 683,340 juvenile Atlantic salmon (Salmo salar) at the Mersey Fish Culture Station occurred during 12-25 August 1988. The salmon parr had been provided with water withdrawn from a depth of 9 m near the bottom of a headpond located on the Mersey River, Nova Scotia. The water was dark brown, smelled of hydrogen sulphide and had a very low concentration of dissolved oxygen. In addition, a reddish-brown material was observed to accumulate in boxes of limestone gravel placed within the hatchery ponds to aerate and alter pH of the incoming water. The same material was observed to adhere to the gill filaments of moribund parr. We suggest that ferrous and manganous bicarbonates were released from the headpond bottom sediments. Release of these bicarbonates occurs under anoxic conditions in the presence of carbon dioxide and a reducing agent such as decomposing organic matter. Subsequent aeration of the water containing ferrous and manganous bicarbonates resulted in the formation of ferric and manganic hydroxides which are insoluble precipitates. Accumulation of ferric and possibly manganic hydroxide on the gill filaments of the salmon parr appeared to cause an impairment of respiratory function which resulted in mortality. Concentrations of hydrogen sulphide in the water supply may also have contributed to the mortality of parr which occurred"--Abstract, page v. Includes abstracts in English and French. Atlantic salmon Mortality Nova Scotia. Hatchery fishes Mortality Nova Scotia. Ferric hydroxides Physiological effect Nova Scotia. Water chemistry Environmental aspects Nova Scotia Mersey River. Saumon atlantique Mortalité Nouvelle-Écosse. Poissons d'élevage Mortalité Nouvelle-Écosse. Hydroxydes ferriques Effets physiologiques Nouvelle-Écosse. Eau Chimie Aspect de l'environnement Nouvelle-Écosse Mersey, Rivière. Canada. Department of Fisheries and Oceans, issuing body. Canada. Department of Fisheries and Oceans. Biological Sciences Branch, issuing body. Canadian manuscript report of fisheries and aquatic sciences ; no. 2016. (CaOODSP)9.505211 PDF 729 KB https://publications.gc.ca/collections/collection_2025/mpo-dfo/fs97-4/Fs97-4-2016-eng.pdf