The web of species interactions - from predation and competition to parasitism and commensalism - has a profound effect on the distribution, abundance, and diversity of organisms in space and time. Normal interactions are influenced by both natural and human-induced conditions that can reshuffle species associations and present considerable problems for conservation and management. This talk provides: (1) an overview of fishing effects on species interactions in the marine realm and the effects on ecosystem resiliency, providing a global view of the problem and consequences; (2) a focus on the interactions that develop around habitat engineered by Red Grouper; and (3) a discussion of the potential consequences to habitat following from overfishing and contact with invasive species. Overfishing removes habitat important to sustaining biological diversity either directly or indirectly while invading species can reduce local biodiversity to such an extent that it has the potential to influence prey availability, parasite loads, and behavior of native species.