Annual Lipid Cycle in Eastern Mosquitofish (Gambusia holbrooki: Poeciliidae) from South Carolina

Storage lipids may be an important energy source for reproduction and may otherwise affect life histories in fish. We collected eastern mosquitofish monthly for one year from two populations in South Carolina to determine annual somatic and reproductive lipid use. In both populations, there was a seasonal shift of lipids from soma to reproduction in early spring. Several other patterns of lipid use indicated energetic trade-offs between somatic storage and reproductive use, and energetic limitations in reproduction were apparent. Fish from the two populations showed consistently different patterns in clutch size, reproductive allocation, and percent lipids devoted to reproduction, indicating either genetically based or environmentally induced differences in life histories. Overall, energy collected during more productive times of the year (late summer and fall) and stored in the form of lipids appeared to be an important component of the reproductive energy budget in spring.