  Transient dynamics can often differ drastically from the asymptotic dynamics
of systems. In this paper we provide a unifying framework for analysing
transient dynamics in marine metapopulations, from the choice of norms to the
addition of stage structure. We use the $\ell_1$ norm, because of its
biological interpretation, to extend the transient metrics of reactivity and
attenuation to marine metapopulations, and use examples to compare these
metrics under the more commonly used $\ell_2$ norm. We then connect the
reactivity and attenuation of marine metapopulations to the source-sink
distribution of habitat patches and demonstrate how to meaningfully measure
reactivity when metapopulations are stage-structured.
