Data fusion can be used to increase the efficacy of both sonar signal processing and tracking of a target of interest. An example of data fusion is the use of information about the positions of interferers as reported by a source external to the sonar system, for instance by the Automatic Identification System. Through the use of such information, a joint likelihood function can be approximately marginalized to represent the likelihood function of a single target of interest. Presented here is an application of such an approach to a data set recorded during the SEABAR 07 sea trial.