Two areas of current concern in the marine environment are: (1) the effects of climate change on higher trophic levels, and (2) ecosystem management with marine protected areas (MPAs). Our current work on climate change addresses how population variability and the sensitivity of population to different frequencies of variability in the environment (e.g., the frequencies of ENSOs) change with fishing. Our current work on MPAs addresses the transient responses of populations to implementation of MPAs for the purpose of analyzing monitoring data for adaptive management of MPAs.