No evidence that the widespread environmental contaminant caffeine alters energy balance or stress responses in fish

Hung Tan, Jack A. Brand, Bradley O. Clarke, Jack L. Manera, Jake M. Martin, Bob B.M. Wong, Lesley A. Alton

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)

Abstract

Anthropogenic sources of environmental pollution are ever-increasing as urban areas expand and more chemical compounds are used in daily life. The stimulant caffeine is one of the most consumed chemical compounds worldwide, and as a result, has been detected as an environmental contaminant in all types of major water sources on all continents. Exposure of wildlife to environmental pollutants can disrupt the energy balance of these organisms, as restoration of homeostasis is prioritised. In turn, energy allocated to other key biological processes such as growth or reproduction may be affected, consequently reducing the overall fitness of an individual. Therefore, we aimed to investigate if long-term exposure to environmentally relevant concentrations of caffeine had any energetic consequences on wildlife. Specifically, we exposed wild eastern mosquitofish (Gambusia holbrooki) to one of three nominal concentrations of caffeine (0, 100 and 10,000 ng/L) and assayed individuals for metabolic rate, general activity, antipredator and foraging behaviour and body size as measures of energy expenditure or energy intake. We found no differences in any measured traits between any of the given exposure treatments, indicating that exposure to caffeine at current environmental levels may not adversely affect the energy balance and fitness of vulnerable freshwater fish.

Original languageEnglish
Pages (from-to)666-678
Number of pages13
JournalEthology
Volume129
Issue number12
DOIs
Publication statusPublished - Dec 2023

Keywords

  • activity
  • antipredator response
  • foraging behaviour
  • Gambusia holbrooki
  • metabolic rate
  • pharmaceutical pollution

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