Fall diel diet composition and feeding activity of American eel (Anguilla rostrata) in a tributary of the Hudson River, NY

American eel (Anguilla rostrata), are a species in decline throughout much of their native range in North America. A better understanding of the ecological role of American eel will help conserve this important species. During autumn 2009,189 eels were collected from Hannacroix Creek, a tributary of the Hudson River, in Albany and Greene counties, NY.  Our objectives were to 1) determine the potential differences in the diet composition of three sizes of American eel; (small (0-175mm total length), medium (176-300mm total length), and large (301+ mm total length)) and 2) determine if there is a difference in day versus night feeding of eels in terms of diet composition and food consumption. Eel diet was quantified based on eel size class and time period; (day and night). A high proportion of sampled eel’s stomachs were empty. American eel diet varied among size classes and diel feeding periods. (p = 0.0010). Small and large eels showed a significant difference in diet between the day and night samplings. Ephemerellidae larvae were the major prey consumed in each period by all size classes.