LE3 .A278 2015

2015

Avery, Trevor

Acadia University

Master of Science

Masters

Biology

Biology

The American eel, Anguilla rostrata, is designated by COSEWIC as a threatened species prompting an increased need for more information about the species’ habitat use and abundance. Very little information is known about American eels in local populations. To address this information gap, a long-term eel monitoring program was implemented in a small protected watershed in Nova Scotia. American eel habitat use, demographics, abundance and trap efficiency was investigated from 2009 – 2012 using capture-mark-recapture (CMR) techniques. Eels were captured in traditional eel traps and minnow traps, and tagged in Oakland Lake. Catch-per-unit-effort (CPUE) was calculated and related to habitats characterized by temperature, dissolved oxygen, pH, vegetation type, substrate composition, depth, and underwater and shoreline slope. Other factors including eel age, length, mass and home range were examined. In total, 842 eels were captured and 368 Passive Integrated Transponder (PIT) tags were implanted. Eels were found in all habitats, but in different habitat areas depending on date of capture (month), but not time of capture (day vs. night). Acoustically tagged eels used all water depths (m), but no eels were captured at depths >3 m. Closed population estimates were calculated using the Schnabel method. Yearly baseline population estimates ranged from 87 to 161 eels. A simulation of variable and fixed capture event durations showed that population estimates are sensitive to the number of traps deployed and timing of trap checks. As well, changes in sampling protocols can affect population estimates. Traps were found to be efficient at catching larger eels. Gaining a better understanding of local American eel populations over time will provide valuable information to aid in habitat conservation and inform eel conservation and management efforts.

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https://scholar.acadiau.ca/islandora/object/theses:410