This is a Nurikabe puzzle, with a twist. It is not allowed to have five consecutive black cells in a row or column. The usual Nurikabe restriction that there can be no two by two squares of black cells is waived and no longer applies.
Sorry for the unannounced break last week. A second Wednesday puzzle will be posted 12 hours from now to compensate. My summer work is winding down now, so I hope to avoid having to do this again in the near future.