  The concept of spectral curve is generalized to open strings in AdS/CFT with
integrability preserving boundary conditions. Our definition is based on the
logarithms of the eigenvalues of the open monodromy matrix and makes possible
to determine all the analytic, symmetry and asymptotic properties of the
quasimomenta. We work out the details of the whole construction for the Y = 0
brane boundary condition. The quasimomenta of open circular strings are
explicitly calculated. We use the asymptotic solutions of the Y -system and the
boundary Bethe Ansatz equations to recover the spectral curve in the strong
coupling scaling limit. Using the curve the quasiclassical fluctuations of some
open string solutions are also studied.
