Tolerance of Hypersaline Water on American Eels (Anguilla rostrata)

Authors: Micaela Felter, Charles Cotton

SUNY Campus: SUNY Cobleskill

Presentation Type: Poster

Location: UU 111

Presentation #: 72

Timeslot: Session B 10:15-11:15 AM

Abstract: American Eels (Anguilla rostrata) are catadromous fish classified as endangered by the IUCN Red List that regularly encounter variable salinity. The goal of the study was to test American Eel tolerance to hypersaline water beyond the normal range of sea level through progressively increasing the salinity in their aquaria. Treatments increased salinity 2 ppt/day by adding 60g salt daily, while control tanks remained in fresh water for the duration of the experiment. Water quality parameters were tested with a YSI probe daily to monitor salinity and dissolved oxygen. Mortality was tracked for control and treatment tanks, and a one-tailed T-test was used to determine significance of survivability. Treatment eels experienced significantly higher mortality (P=0.000171), with 50% mortality observed at 36-38ppt, and the final eel perished at 51.89 ppt. The Eel Swimbladder Nematode (Anguillicola crassus)was observed in both control and treatment eels, noted by the inability to deflate their swim bladder and regulate position in the water column. This parasite is common in American Eels but may have influenced results of this study. Results from this study, combined with previous studies done on temperature and pH tolerance, indicate Anguillid eels are very tolerant to unfavorable water quality. With conservation efforts focused on dam removals, habitat restoration, and restriction on use for bait eels (like the ones used for this study), this information will be useful for prudent management of American Eels.