RESUMEN
In this study, we sampled yellow perch from three lakes along a metal-contamination gradient and examined their olfactory ability in response to conspecific chemical alarm cues and metal-binding characteristics of their olfactory epithelium (OE). We measured the electrophysiological response at the OE, tested their antipredator behaviour and measured neuronal density at the olfactory rosette and bulb. Yellow perch from contaminated lakes exhibited significantly larger electrophysiological responses to alarm cues than clean lake fish, but showed no antipredator behaviour contrary to clean lake fish. Neuron density did not differ at either the olfactory rosette or bulb between clean and contaminated fish. Unlike fishes raised under laboratory or aquaculture settings, fish from contaminated lakes possessed a functional OE after metal exposure, but similar to laboratory/aquaculture fishes, yellow perch did not exhibit olfactory-mediated behaviours. Thus, wild fish from contaminated lakes can detect chemical stimuli but olfactory signal processing is disrupted which could alter ecological functioning.
Asunto(s)
Metales/toxicidad , Trastornos del Olfato/inducido químicamente , Bulbo Olfatorio/efectos de los fármacos , Vías Olfatorias/efectos de los fármacos , Neuronas Receptoras Olfatorias/efectos de los fármacos , Percas , Contaminantes Químicos del Agua/toxicidad , Animales , Conducta Animal/efectos de los fármacos , Conducta Animal/fisiología , Recuento de Células , Electrofisiología , Monitoreo del Ambiente , Potenciales Evocados Somatosensoriales/efectos de los fármacos , Potenciales Evocados Somatosensoriales/fisiología , Agua Dulce/análisis , Agua Dulce/química , Branquias , Trastornos del Olfato/fisiopatología , Bulbo Olfatorio/fisiopatología , Vías Olfatorias/fisiopatología , Percepción Olfatoria/efectos de los fármacos , Percepción Olfatoria/fisiología , Neuronas Receptoras Olfatorias/fisiología , Natación/fisiologíaRESUMEN
Branchial binding kinetics and gastro-intestinal uptake of copper and cadmium where examined in yellow perch (Perca flavescens) from a metal-contaminated lake (Hannah Lake, Sudbury, Ontario, Canada) and an uncontaminated lake (James Lake, North Bay, Ontario, Canada). An in vivo approach was taken for gill binding comparisons while an in vitro gut binding assay was employed for gastro-intestinal tract (GIT) uptake analysis. By investigating metal uptake at the gill and the gut we cover the two main routes of metal entry into fish. Comparisons of water and sediment chemistries, metal burdens in benthic invertebrate, and metal burdens in the livers of perch from the two study lakes clearly show that yellow perch from Hannah L. are chronically exposed to a highly metal-contaminated environment compared to a reference lake. We found that metal-contaminated yellow perch showed no significant difference in gill Cd binding compared to reference fish, but they did show significant decreases in new Cd binding and absorption in their GITs. The results show that gill Cd binding may involve low-capacity, high-affinity binding sites, while gastro-intestinal Cd uptake involves binding sites that are high-capacity, low-affinity. From this we infer that Cd may be more critically controlled at the gut rather than gills. Significant differences in branchial Cu binding (increased binding) were observed in metal-contaminated yellow perch. We suggest that chronic waterborne exposure to Cu (and/or other metals) may be the dominant influence in gill Cu binding rather than chronic exposure to high Cu diets. We give supporting evidence that Cd is taken up in the GIT, at least in part, by a similar pathway as Ca(2+), principally that elevated dietary Ca(2+) reduces Cd binding and uptake. Overall our study reveals that metal pre-exposure via water and diet can alter uptake kinetics of Cu and Cd at the gill and/or the gut.