Bioenergetic costs of heavy metal exposure in yellow perch (Perca flavescens): in situ estimates with a radiotracer (¹³⁷Cs) technique

Abstract

While the flow of energy is understood to determine the growth of organisms and the productivity of ecosystems, little is known about the sublethal effect of pollutants on the energetic efficiency of wild populations. We used field estimates of fish growth coupled to in situ estimates of food consumption rates obtained from the mass balance of a globally dispersed, trophically transferred radiotracer ( 137 Cs) to demonstrate the bioenergetic impairment of yellow perch (Perca flavescens) from lakes polluted by heavy metals (Cd, Cu, and Zn). Annual growth increment relative to the total energy budget (conversion efficiency) was about three times lower in cortisol-impaired yellow perch from metal-polluted lakes relative to yellow perch from reference lakes (4.2% compared with 10.8%), suggesting that fish exposed to pollutants experienced greater total energetic costs. In addition, metal-polluted lakes were dominated by adult yellow perch populations and simplified prey bases, suggesting that effects are occurring at multiple levels of biological organization. Our in situ bioenergetic approach to toxicity assessment provides a measurable and ecologically relevant endpoint for assessing the sublethal effects of pollutants on fish communities.Résumé : Bien qu'on sache que le flux d'énergie détermine la croissance des organismes et la productivité des écosys-tèmes, on sait peu de choses de l'effet sublétal des polluants sur l'efficacité énergétique des populations sauvages. Nous avons utilisé des estimations de la croissance des poissons dans la nature couplées à des estimations des taux d'alimentation in situ obtenues à partir du bilan massique d'un radiotraceur présent partout sur la Terre et transmis par voie trophique ( 137 Cs) pour déterminer la perturbation bioénergétique de la perchaude (Perca flavescens) de lacs pollués par des métaux lourds (Cd, Cu et Zn). L'incrément annuel de croissance en rapport avec le bilan énergétique global (efficacité de conversion) était environ 3 fois plus bas chez les perchaudes des lacs pollués par les métaux, dont le mé-tabolisme du cortisol était perturbé, que chez les perchaudes de lacs témoins (4,2% comparativement à 10,8%), ce qui indique que les coûts énergétiques totaux sont plus élevés chez les poissons exposés aux polluants. De plus, dans les lacs pollués par les métaux, les populations de perchaudes adultes étaient dominantes et la diversité des proies était faible, ce qui laisse penser que les effets des polluants se font sentir à divers niveaux du biote. Notre approche bioéner-gétique in situ en matière d'évaluation de la toxicité offre un paramètre mesurable et écologiquement pertinent pour évaluer les effets sublétaux des polluants sur les communautés de poissons.[Traduit par la Rédaction] Sherwood et al. 450

Effects of Cu on plasma cortisol and cortisol secretion by adrenocortical cells of rainbow trout (Oncorhynchus mykiss)

“…Numerous field studies reported that the condition factor is lower in fish exposed to mixtures of metals, through alterations of enzymatic capacity (Lévesque et al, 2003;Couture and Kumar, 2003) and in some situations, alterations of the food basis in contaminated lakes (Sherwood et al, 2000;Iles and Rasmussen, 2005). Exposure to Cu alone decreased the condition factor and hepatosomatic index in this study, however whether these effects were caused by reduced food consumption or a less efficient capacity to transform food into biomass was not determined.…”

Live Fast and Die Young: Metal Effects on Condition and Physiology of Wild Yellow Perch from along Two Metal Contamination Gradients

“…Fish allocate energetic resources to detoxify metals taken up through food or water, and the presence of relatively high environmental metal concentrations may reduce food availability if concentrations are high enough to induce toxicity in food organisms (Sherwood et al 2000). However, published studies investigating morphometric condition in wild yellow perch populations have led to contradictory conclusions in the literature.…”

“…These lakes are rapidly recovering and today, brown bullhead (Ameiurus nebulosus), pumpkinseed (Lepomis gibbosus), and various minnows can be captured in Hannah Lake, while Whitson Lake also shelters a growing population of northern pike (Esox lucius) and walleye (Sander vitreus; unpublished data). Yellow perch is also a dominant species in metal-contaminated lakes of Rouyn-Noranda (Sherwood et al 2000).…”

Seasonal and Regional Variations of Metal Contamination and Condition Indicators in Yellow Perch (Perca flavescens) along Two Polymetallic Gradients. I. Factors Influencing Tissue Metal Concentrations

“…Lakes surrounding the industrial region of Rouyn-Noranda in northwestern Québec have been affected by mining and smelting operations since about 1927 (Couillard et al 1993). Although the extent of industrial contamination is considerably smaller in the Rouyn-Noranda region than in Sudbury, recent studies have demonstrated elevated concentrations of Cd, Cu, and Zn in contaminated lakes relative to background concentrations (Couillard et al 1993;Brodeur et al 1997;Laflamme et al 2000;Sherwood et al 2000;Levesque et al 2002).…”