Given a fibered link, consider the characteristic polynomial
of the monodromy restricted to first homology. This generalizes
the notion of the Alexander polynomial of a knot. We define
a construction, called iterated plumbing, to create a sequence
of fibered links from a given one. The resulting sequence
of characteristic polynomials for these links has the same
form as those arising in work of Salem and Boyd in their study
of distributions of Salem and P-V numbers. From this we deduce
information about the asymptotic behavior of the large roots
of the generalized Alexander polynomials, and define a new
poset structure for Salem fibered links.