back to first page [..][[BR]] back to ["Strategy analysis -Description"][[BR]] To predict and explain the presence-absence of yellow eel in relation to environmental variables, we used generalized additive models (GAMs) (Hastie and Tibshirani, 1990). Generalized Additive Models (GAM) are very similar to generalised linear models, but they also allow for including non-linear terms in the linear predictor term (Hastie and Tibshirani, 1990; Wood, 2006).