Thermosensitive period of sex determination in the coral-reef damselfish Acanthochromis polyacanthus and the implications of projected ocean warming

Rodgers, G.G., Donelson, J.M., and Munday, P.L. (2017) Thermosensitive period of sex determination in the coral-reef damselfish Acanthochromis polyacanthus and the implications of projected ocean warming. Coral Reefs, 36 (1). pp. 131-138.

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Abstract

Higher temperatures associated with climate change have the potential to significantly alter the population sex ratio of species with temperature-dependent sex determination. Whether or not elevated temperature affects sex determination depends on both the absolute temperature experienced and the stage of development at which the thermal conditions occur. We explored the importance of exposure timing during early development in the coral reef fish, Acanthochromis polyacanthus, by increasing water temperature 1.5 or 3 °C above the summer average (28.5 °C) at different stages of development. We also measured the effect of treatment temperature on fish size and condition, in order to gauge how the thermal threshold for sex-ratio bias may compare with other commonly considered physiological metrics. Increasing grow-out temperature from 28.5 to 30 °C had no effect on the sex ratio of offspring, whereas an increase to 31.5 °C (+3 °C) produced a strong male bias (average ~90%). The thermosensitive period for this species lasted between 25 and 60 d post hatching, with the bias in sex ratio greater the earlier that fish experienced warm conditions. Temperatures high enough to bias the sex ratio are likely to be seen first during late summer (January and February) and would affect clutches produced late in the breeding season. There was no change to fish condition in response to temperature; however, the two higher temperature treatments produced significantly smaller fish at sampling. Clutches produced early in the season could buffer the population from a skewed sex ratio, as their development will remain below the thermal threshold; however, continued ocean warming could mean that clutches produced earlier in the breeding season would also be affected in the longer term. A skewed sex ratio could be detrimental to population viability by reducing the number of females in the breeding population.

Item ID: 46576
Item Type: Article (Research - C1)
ISSN: 1432-0975
Keywords: temperature-dependent sex determination, sex ratio, environmental sex determination, climate change, thermal sensitivity
Funders: ARC Centre of Excellence for Coral Reef Studies (CECRS)
Research Data: http://dx.doi.org/10.4225/28/57997DE4D306A
Date Deposited: 05 Dec 2016 22:10
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 50%
06 BIOLOGICAL SCIENCES > 0699 Other Biological Sciences > 069902 Global Change Biology @ 50%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960305 Ecosystem Adaptation to Climate Change @ 100%
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