In this paper, we examine a problem of autonomous vehicle decision making for search operations performed by undersea autonomous vehicles. Specifically, we consider the problem of determining whether to continue with preplanned search paths or to switch to focused local search efforts in the presence of limited contact information. Using techniques from information theory, we develop a context of search channel capacity from which rapid computations of performance bounds can be computed based on sensing capabilities and prior search information. These bounds characterize search planning alternatives and are useful in making the initial online determination of search plan adaptation. We illustrate the utility of our approach with numerical examples applying multiple undersea searchers.