Chronic exposure to low concentrations of waterborne cadmium during embryonic and larval development results in the long-term hindrance of antipredator behavior in zebrafish

• Published in: Environmental toxicology and chemistry Vol. 27; no. 3; pp. 705 - 710
• Main Authors: Kusch, Robin C., Krone, Patrick H., Chivers, Douglas P.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Periodicals, Inc 01.03.2008; Blackwell Publishing Ltd
• Subjects: Aging; Alarm cues; Animal behavior; Animals; Behavior, Animal - drug effects; Cadmium; Cadmium - toxicity; chronic toxicity; Danio rerio; dose response; Dose-Response Relationship, Drug; ecotoxicology; embryo (animal); Embryo, Nonmammalian - drug effects; embryogenesis; Embryonic development; environmental exposure; escape behavior; Fish; fish larvae; foraging; Freshwater; Larva - drug effects; Larval development; Mortality; Olfaction; predator-prey relationships; Random Allocation; Time Factors; Trout; Water - chemistry; water pollution; Zebrafish
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1897/07-273.1

Cadmium has been recognized for some time as a potent environmental pollutant with the capability of disrupting olfactory‐mediated behaviors. Failing to respond to chemical cues in the environment could adversely affect foraging, reproduction and predator avoidance. Recognizing this impaired perception as a serious ecological problem has been undermined by the fact that the damage is often reversible; short depuration periods of 5 d may allow for the re‐establishment of responses to chemical cues. In this experiment, early life stage zebrafish were continuously exposed for 50 d at 0, 0.2, 2.0, and 20 μg Cd/L. The subjects were depurated for 14 d and then subjected to behavioral testing where antipredator responses to chemical alarm cues were observed. Our data show that continuous exposure during rearing to a concentration as low as 20 μg Cd/L is sufficient at eliminating antipredator behavior in zebrafish (Danio rerio) even after the source of the cadmium had been removed for 14 d. Furthermore, subjects raised under a 10‐fold lower concentration also showed alteration in their behavioral responses, taking significantly longer to respond to the predation threat. Exposure to low levels of cadmium throughout development may alter neurogenesis, subsequently resulting in long‐term impairment of chemical cue perception.