In this chapter, we describe methods for sampling commercial fisheries and identify factors affecting the design of sampling plans. When sampled properly, commercial fisheries can provide important information on the response of aquatic organisms to exploitation; such information can be used by management agencies to develop regulations for ensuring long-term production of the resource and long-term economic benefit. Fishery statistics are typically used to estimate abundance, mortality, recruitment, growth, and other vital characterisitcs of populations. Fishery statistics can also be used to study changes in fish community composition resulting from differential exploitation of species.