  We exhibit a sufficient condition in terms of decay at infinity of the
initial data for the finite time blowup of strong solutions to the
Camassa--Holm equation: a wave breaking will occur as soon as the initial data
decay faster at infinity than the solitons. In the case of data decaying slower
than solitons we provide persistence results for the solution in weighted
$L^p$-spaces, for a large class of moderate weights. Explicit asymptotic
profiles illustrate the optimality of these results.
