Abundance in Bottom Sediments and Hatching Requirements of Eggs ofCentropages hamatus(Copepoda: Calanoida) From the Alligator Harbor Region, Florida

Abstract

The distribution and abundance of Centropages hamatus eggs in the upper 5 cm of the sea-bottom of the Alligator Harbor region, Florida, was determined. The hatching of these eggs at 4, 10, 15, 19, and room temperature (20-25°C) was monitored in the laboratory. Hatching only occurred at temperatures less than 20°C. Eggs produced by C. hamatus individuals that were reared in the laboratory at 19°C, 20L-4D did not hatch at 19°C. A 60% hatch was induced by incubating these eggs at room temperature (22-25°C) for 60 days followed by cooling at 15°C. The results indicate that C. hamatus produces diapause eggs that are capable of surviving warm temperatures characteristic of late spring and summer months. Since planktonic phases of this species are not present in the water column at temperatures greater than 20°C, it appears that diapause is a critical life history stage without which the life cycle would be broken.