LE3 .A278 2013

2013

Avery, Trevor
Cairns, David

Acadia University

Master of Science

Masters

Biology

Biology

Despite intense conservation interest in the American eel (Anguilla rostrata), there exists no robust data source from which to assess population status of this panmictic species. To address a key information need, eel distribution in saline waters was evaluated by compiling eel count and presence/absence data from 25 saline (i.e. brackish and salt water) surveys involving ca. 238,000 data points between 1959 and 2012. Surveys on the east coast of Canada indicated a virtual absence of capture of American eels in open saline waters; however, US surveys had varied and higher numbers of eels. Eel captures were classified based on exposure to the sea as defined in a habitat atlas compiled by Cairns et al. (2012) that examined preferred eel habitat compiled from eel fisheries data. Trends showed that the majority of eels occupy sheltered and semi-exposed saline waters; in particular, those waters of large bays and sounds in the USA. Mean depths and kilometers-to-land indicate that eels prefer shallow, near-shore waters. Preliminary Poisson, Negative Binomial, and binary models were constructed to explore relationships between eel numbers and exposure categories including continuous variables of depth, kilometers-to-land and latitude. Model fit, data sensitivity, and the effect of zero inflation were examined. Both trend analyses and modeling, in their current state, provide significant evidence of broad spatial and temporal habitat usage in saline environments by the American eel, and identify sheltered coastal waters and semi-exposed bays and sounds as primary saline habitat. The analysis presented here provides a methodology for investigating temporal and spatial questions such as habitat usage for other geographically widespread organisms that suffer from a lack of data.

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https://scholar.acadiau.ca/islandora/object/theses:301