Climate change and pollution speed declines in zebrafish populations.
Endocrine disrupting chemicals (EDCs) are potent environmental contaminants, and their effects on wildlife populations could be exacerbated by climate change, especially in species with environmental sex determination. Endangered species may be particularly at risk because inbreeding depression and stochastic fluctuations in male and female numbers are often observed in the small populations that typify these taxa. Here, we assessed the interactive effects of water temperature and EDC exposure on sexual development and population viability of inbred and outbred zebrafish (Danio rerio). Water temperatures adopted were 28 °C (current ambient mean spawning temperature) and 33 °C (projected for the year 2100). The EDC selected was clotrimazole (at 2 μg/L and 10 μg/L), a widely used antifungal chemical that inhibits a key steroidogenic enzyme [cytochrome P450(CYP19) aromatase] required for estrogen synthesis in vertebrates. Elevated water temperature and clotrimazole exposure independently induced male-skewed sex ratios, and the effects of clotrimazole were greater at the higher temperature. Male sex ratio skews also occurred for the lower clotrimazole exposure concentration at the higher water temperature in inbred fish but not in outbred fish. Population viability analysis showed that population growth rates declined sharply in response to male skews and declines for inbred populations occurred at lower male skews than for outbred populations. These results indicate that elevated temperature associated with climate change can amplify the effects of EDCs and these effects are likely to be most acute in small, inbred populations exhibiting environmental sex determination and/or differentiation.
AstraZeneca Global Environment, Macclesfield, Cheshire SK10 4TF, United Kingdom; Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, Devon EX4 4QD, United Kingdom;
A Ross
http://orcid.org/0000-0002-3892-8993
AR
Brown
AstraZeneca Global Environment, Macclesfield, Cheshire SK10 4TF, United Kingdom;
Stewart F
SF
Owen
AstraZeneca Global Environment, Macclesfield, Cheshire SK10 4TF, United Kingdom;
James
J
Peters
AstraZeneca Global Environment, Macclesfield, Cheshire SK10 4TF, United Kingdom;
Yong
Y
Zhang
Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, Devon EX4 4QD, United Kingdom; Centre for Environment, Fisheries, and Aquaculture Science, Lowestoft, Suffolk NR33 0HT, United Kingdom;
Marta
M
Soffker
Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, Devon EX4 4QD, United Kingdom;
Gregory C
GC
Paull
Centre for the Environment and Conservation, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom; and.
David J
DJ
Hosken
Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.
M Abdul
MA
Wahab
Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, Devon EX4 4QD, United Kingdom; ross.brown@exeter.ac.uk.
Charles R
CR
Tyler
D000818:Animals; D057231:Climate Change; D003022:Clotrimazole / Q000633:toxicity; D004781:Environmental Exposure / Q000032:analysis; D004787:Environmental Pollution / Q000032:analysis*; D005260:Female; D005854:Germ Cells / Q000166:cytology / Q000187:drug effects; D006066:Gonads / Q000187:drug effects; D007178:Inbreeding; D008297:Male; D008954:Models, Biological; D011157:Population Dynamics; D013696:Temperature; D013997:Time Factors; D015027:Zebrafish / Q000254:growth & development*
D003022:Clotrimazole
additive; interaction; population; stressors; viability