Stable isotope analysis

by Jessica Gedeon, Aquatic Research Technician

Over the course of the summer, you may have heard about the GMRC American Eel Project we had begun to better understand the movement of the American eel within the Restigouche River estuary and to identify its critical habitat. Wrapping up this year’s fieldwork, Carole-Anne and I spent a few days in the GMRC lab finishing up the prey sample preparations to be sent off to the UNB SINLab for stable isotopic analysis.

To do this, we start by taking fresh and brackish water prey samples, drying them out in an oven for at least 24 hours, and further withdraw moisture by placing the samples in a desiccant chamber. Dried samples are then grinded up into a fine powder and placed in labeled Eppendorf vials for shipment.

These prey samples will be analyzed for their unique isotopic signature, and will be compared to American eel fin clip samples/signatures, to correlate feeding patterns with prey distribution for our river system. Basically, by comparing the “make-up” of different aquatic species from different areas of the river that the American eel eat, and then comparing this to what we find present in the eels’ fins, we can identify where the eel is eating, and how it may be moving within its