Identification of Nauplii N1–N6 and Copepodids CI–CVI of the Great Lakes Calanoid and Cyclopoid Copepods (Calanoida, Cyclopoida, Copepoda)

Abstract

Most copepods have twelve post-embryonic developmental stages. Current keys permit identification of only the adults, one-twelfth of the stages, to species. Each immature copepod is of a certain species and a certain stage, and distinguishable in the older stages, a certain sex. This paper presents keys and alternative chart methods for identifying calanoid and cyclopoid nauplii N1–N6, calanoid copepodids CI–CVI, and cyclopoid copepodids CI–CVI to species, stage, and sex for the twelve common species of copepods in the Great Lakes. The keys are based on the most convenient characteristics, but the charts provide a broader choice of characters to be used in various combinations, especially when the convenient characters are missing or not visible. The charts are particularly applicable for fish stomach analyses and when characters are obscured due to omitting or limiting dissections. The charts also summarize some of the key characters for quick reference after an expertise is achieved.