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Using ecological models to investigate stressor effects throughout the life cycle of mummichogs
Citation:
Clark, B., R. Downing, J. Bishop, I. Kirby, D. Champlin, T. Bosker, K. Watanabe, J. Nishimura, AND D. Nacci. Using ecological models to investigate stressor effects throughout the life cycle of mummichogs. NAC-SETAC 23rd Annual Meeting, Amherst, Massachusetts, June 14 - 16, 2017.
Impact/Purpose:
It is always necessary to make sure that the animal models we develop in the laboratory reflect what actually happens to wild animals. We worked with a well-studied and common estuarine fish the mummichog (Fundulus heteroclitus) and made many laboratory measurements of how various levels of pollution affected the growth, feeding, and reproduction of the fish. We then compared our laboratory measurements to those made on a wild mummichog population. These data and models will be used to improve our predictions of the effects of chemicals and other stressors on fish populations.
Description:
Ecological models of mummichogs (Fundulus heteroclitus) provide valuable tools to link controlled laboratory experiments to field observations. Mummichogs are useful study organisms due to their amenability to laboratory conditions, the availability of well-developed molecular tools, and their rich history in ecology and evolution. To understand the effects of chemicals and other stressors on population persistence, we are developing and testing a mathematical model of fecundity and dynamic energy budget which will ultimately be integrated into individual-based model of population persistence. Utilizing data from laboratory-based pair and small group spawning, an oocyte growth and spawning model developed for fathead minnow (Pimephales promelas) was modified for mummichog. To determine the comparability of laboratory experiments using small numbers of individuals to natural populations, we assessed the reproductive status and energetic reserves of mummichogs held in the lab, and those collected in Succotash Marsh, Jerusalem, RI during breeding season (July 2016). Fish were collected by seine at the same tidal stage on multiple days throughout the lunar cycle, and the abundance of individuals in four size-classes (80 mm) was recorded. Consistent with a resource-rich environment, the laboratory-bred fish were more likely to have mature oocytes than the field-caught 41-60 mm fish, and they had a much greater mass of body fat and greater hepatosomatic indices. These data, along with an ongoing laboratory-based growth and reproduction experiments, are being used to refine the fecundity and bioenergetics models. This combination of laboratory experiments, field study and ecological models provide a testable system to predict the effects of stressors on the tradeoffs throughout the mummichog lifecycle between energy storage, growth, and reproduction.