title: The Effects of Two Rearing Salinities on Survival and Stress of Winter Flounder Broodstock.
abstract: The goal of this study was to determine rearing conditions that would improve the survival of broodstock of winter flounder Pleuronectes americanus. We hypothesized that keeping wild winter flounder in iso-osmotic water would reduce the energy costs related to osmoregulation; the resulting energy gain could then be used for growth or immune responses. Eighty fish were randomly separated into four tanks, two containing seawater (SW; 28.7 ± 0.9‰ (mean ± SD)) and two containing brackish water (BW; 14.7 ± 1.7‰). Fish were sampled after 2 and 5 months of captivity for evaluation of their condition and stress status. Between the second and fifth months, the condition index increased significantly in both salinity groups, whereas body water content decreased. No salinity effect in terms of growth, condition, or energy reserves was found. However, the fish in BW showed much lower mortality. We found that the fish in SW had higher levels of the physiological indicators of stress than those in BW, which could have increased the risk of opportunistic infections in the former. Also, thrombocytes were absent in the SW fish after 2 months of captivity, which may have contributed to some mortalities. The lower resistance of certain opportunistic pathogens to BW is another possible explanation as to why fish in BW had lower occurrences of infectious diseases.
authors.affiliation: a Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski , 310 Allée des Ursulines , Rimouski , Quebec , G5L 3A1 , Canada.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Plante
authors.affiliation: a Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski , 310 Allée des Ursulines , Rimouski , Quebec , G5L 3A1 , Canada.
authors.forename: Céline
authors.initials: C
authors.lastname: Audet
authors.affiliation: b Institut Maurice-Lamontagne, Pêches et Océans Canada , 850 Route de la Mer , Mont-Joli , Quebec , G5H 3Z4 , Canada.
authors.forename: Yvan
authors.initials: Y
authors.lastname: Lambert
authors.affiliation: c Groupe de Recherche en Recyclage Biologique et Aquiculture, Pavillon Paul-Comtois, Université Laval, Cité Universitaire Québec , Quebec , G1K 7P4 , Canada.
authors.forename: Joël
authors.initials: J
authors.lastname: de la Noüe