Habitat can be defined as the place where the organism lives including all its physical, chemical and biological dimensions (Odum 1971; Hoss and Thayer 1993). These dimensions include water quality, physical structure, flow regime and biotic interaction. Essential fish habitat (EFH) is further defined as “those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity” (Magnuson-Stevens Act, 16 U.S.C. 1801 et seq.) With new mandates to identify and protect EFH for all species managed under fisheries management plans, evaluation of fish habitat has become a priority. The methods used to identify and define essential fish habitat have ranged from intensive microscale sampling to coarse macroscale delineations. Historically, assessment of fish habitat occurred on small scales and addressed water quality, physical structure and prey/predator interactions. With increases in geographic information systems (GIS) capabilities, large-scale depictions of fish distributions have been completed, however, these surveys often lack the detail necessary to describe the processes driving distribution. Research at both scales is necessary to accurately define and describe essential fish habitat. Macroscale assessments of fish distribution, linked with process-oriented experiments will elucidate the driving forces behind distribution and allow for a more complete identification of essential habitat
