Survival and Habitat of Yellow‐Phase American Eels in North Carolina Tidal Creeks

Abstract

AbstractWe estimated rates of survival as well as effects of habitat on catch rates of juvenile yellow‐phase American Eels Anguilla rostrata in southeastern U.S. tidal creeks. We trapped and marked eels with PIT tags at 24 fixed sites in eight North Carolina tidal creeks and then recaptured and resighted the tagged individuals to estimate apparent survival. Separate Cormack–Jolly–Seber (CJS) models were fitted to mark–recapture data (eight creeks) versus mark–resight data (four creeks) to estimate apparent survival. Median annual apparent survival (Φ) was higher when the CJS model was fitted to mark–resight data (Φ = 0.15) than to mark–recapture data (Φ = 0.013). Negative binomially distributed models were fitted to catch rates of both tagged and untagged eels to test for habitat, development, and seasonal effects. The presence/absence of culverts and season were meaningful covariates of catch rates; greater catches were found at sites possessing culverts and during the spring. Other habitat and development factors at the site, creek, and watershed levels were not important covariates of catch rates. Partitioning the sources of loss of yellow‐phase American Eels from these systems into mortality versus emigration would be useful future research in the southeastern U.S. coastal region. Further study into how culverts affect yellow‐phase American Eel habitation and movement in southeastern U.S. estuaries is also warranted.