Due to their important ecological function, areas of the offshore pelagic environments discussed above and the associated benthic habitats represent essential fish habitat-habitat areas of particular concern (EFH-HAPC) and were designated as such though previous Council actions (see SAFMC Comprehensive Habitat Amendment; SAFMC, 1998c). These include The Point, The Ten-Fathom Ledge, and Big Rock (North Carolina); The Charleston Bump and the Georgetown Hole (South Carolina); for species in the Snapper Grouper complex, Coastal Migratory Pelagic species including dolphin and Coral and Live/Hard Bottom Habitat. Additional EFH-HAPCs were designated for Coastal Migratory Pelagics including: Amberjack Hole (The Point) off Jupiter Inlet (Florida); The Hump off Islamorada, Florida; The Marathon Hump off Marathon, Florida; and The "Wall" off of the Florida Keys. These areas are productive and highly dynamic oceanic areas. A quasi-permanent, cyclonic eddy with attendant upwelling of nutrient-rich, deep water sets-up in the wake of the Charleston Bump. Upwelling results in persistent primary and secondary production that may well result in an important, if not essential feeding environment for the larvae of fishes that congregate to spawn there. The hydrodynamics of the eddy may well serve in the retention of fish propagules that are lost from local populations elsewhere through entrainment into the Gulf Stream. "The Point" off Cape Hatteras is also highly productive due to the confluence of as many as four water masses. Adults of highly migratory species congregate in this area, while the diversity of larval fishes found there is truly astounding (Table 18b of the Habitat Plan (SAFMC, 1998b)). Other water column habitats with high production or dynamic bottom habitats include "Big Rock" and "The Ten Fathon Ledge". Other areas where water flow is affected by bottom habitat concentrating bait and increasing availability of pelagic habitat like Sargassum, include "The Georgetown Hole" off South Carolina.
Section 600.815 (a) (8) of the final rule on essential fish habitat determinations recognizes that subunits of EFH may be of particular concern. Such areas, termed Essential Fish Habitat-Habitat Areas of Particular Concern (EFH-HAPCs), can be identified using identification of habitat areas of particular concern. FMPs should identify specific types or areas of habitat within EFH as habitat areas of particular concern based on one or more of the following considerations: (i) The importance of the ecological function provided by the habitat; (ii) The extent to which the habitat is sensitive to human-induced environmental degradation; (iii) Whether, and to what extent, development activities are, or will be, stressing the habitat type; and (iv) The rarity of the habitat type.