Threshold temperature constraints on reproduction of the banded killifish (Fundulus diaphanus)

Abstract

Banded killifish (Fundulus diaphanus) are a small, freshwater fish that have a wide distribution in eastern North America and are considered a species-at-risk on the island of Newfoundland. We posit that because Newfoundland’s summer climate is much cooler than other locations at similar latitudes, there may be different constraints on banded killifish reproduction. We measured embryonic development under four temperatures (10, 16, 22, and 28 °C) and two conductivities (0.6 and 1.2 mS/cm). Warmer temperatures led to more developed embryos prior to death in embryos that ultimately did not hatch, higher hatch success, faster hatch time, and fewer thermal units to hatch. Conductivity and temperature interacted to affect hatch size. Therefore, banded killifish are likely challenged by the low temperature and conductivity conditions in Newfoundland which may result in reproductive constraints, and perhaps complete cohort failures in relatively cool summers.

Keywords:

• Compensatory development
• thermal adaptation
• degree days
• range edge

Acknowledgements

The authors would like to thank V. Shikon for help in the field, S. Trueman for help with data analysis, and I.A. Fleming, T.E. Van Leeuwen, C. Brown, M. Abrahams, S. Einum, and two anonymous reviewers for comments on an earlier version of the manuscript.

Disclosure statement

The authors report no conflict of interest.

Notes on contributors

All authors contributed to the conception of the project. HDP and MAL ran the experiment and collected data. HDP conducted the statisitcal analyses, and all authors contributed to the writing and editing process.

Additional information

Funding

Funding for this project was provided by Memorial University of Newfoundland Undergraduate Funding (Summer Undergraduate Research Award) to MAL, the Natural Sciences and Engineering Research Council of Canada through a graduate scholarship to HDP and a Discovery grant (355507-2008) to CFP, and grants from the Canada Foundation for Innovation (CFI 19360), and the Research and Development Corporation of Newfoundland and Labrador to CFP

.