East River, Chester Elver Abundance Study

Project Summary

The East River is located in Chester, Nova Scotia and is home to the American eel. Adult eels leave our freshwater rivers to travel to the Sargasso Sea where they spawn. Young American eels, called elvers, then travel up the eastern seaboard back into east coast rivers to mature and continue the cycle.

An Elver Abundance Study is currently being conducted by BCAF in the East River, Chester as a continuation of research that was originally carried out by Fisheries and Oceans Canada (DFO) in the late 1990’s. The present BCAF study will run for 3 years. The first year began in 2008 and will continue through to 2010, this being the final year for counting the elver runs. The purpose of this project is to determine the abundance of elvers and recruitment of larger eels on the East River, Chester. There is also a commercial elver fishery on this waterway. Data from the commercial harvest, past DFO research, and BCAF's current study can be compared to assess the health of the elver populations and determine if the elvers are being harvested in a sustainable manner. (Picture #4)

The trap designed to capture the elvers uses water flow to lure the eels, as they are attracted to the current. Small ramps with flowing water enable the elvers to climb up the ramps and be flushed into an adjoining holding box. Elvers primarily run at night and are influenced heavily by the tides; therefore, traps are checked and emptied early every morning. Researchers remove and measure the total mass of elvers in each trap and conduct biological sampling on a sub-sample of individuals. Once measured, the elvers are released further upstream from the falls. The study starts annually in early spring between April and May. Timing of the runs varies on conditions, but generally the elvers begin entering the rivers once they have reached about 10°C. The study ended the middle of June in 2008; however, the project end date for the 2009 and 2010 studies is mid July.