Seasonal abundance of the nudibranch Dondice jupiteriensis on the colonial hydroid Eudendrium carneum

Benthic colonial hydroids often serve as a host to a large variety of invertebrate taxa. The colonial hydroid Eudendrium carneum Clarke, 1882 is host to a variety of epifauna, including the recently described nudibranch Dondice jupiteriensis García—Méndez & Valdés, 2022. Like many species of heterobranch sea slugs, little is known about the natural history and population biology of D. jupiteriensis. Here we describe a year—long study recording the population density and size structure of D. jupiteriensis on E. carneum colonies in Tampa Bay, FL USA. We found that the D. jupiteriensis population persists year—round but is the densest during the summer months. This coincides with the time period when individual slugs were the smallest, suggesting the population increase in the summer is likely due to larval recruitment. Additionally, 13 other species of heterobranch sea slugs were found inhabiting E. carneum over the course of the study, although none of them were as numerous as D. jupiteriensis. This study provides the first available information on the ecology and population biology of the recently described nudibranch D. jupiteriensis.