Hard Bottom

Use the map below to explore the known hard bottom habitat in North Carolina. If the map is not displaying properly, view it in a standalone browser window.

Hard bottom habitat generally occurs in the ocean where rocks or other hard surfaces are exposed from bottom sand or mud. These hard surfaces, called reefs, can be naturally occurring, like rocks, or can be man-made, like shipwrecks or jetties. When hard bottom habitat is man-made it is called an artificial reef. In North Carolina, artificial reefs have been constructed from surplus vessels, steel boxcars, concrete pipe, concrete rubble, rock, boat molds, tires, and surplus military aircraft.

Function of Hard Bottom Habitat

Function of Hard Bottom Habitat

Hard bottom provides hard, complex, vertical structure where sponges, seaweed and coral can attach. These organisms are the foundation of diverse communities of reef fishthat include snapper and grouper, which are prized by fishermen by both commercial and recreational fishermen.

Waves and organisms turn the hard surfaces into fresh sand for the coastline. Waves, constantly pounding on hard bottom, break off and refine chunks of rocks, slowly turning them into fine sand. Organisms, like bivalves, burrow through hard surfaces, detaching pieces of rock along the way, while macroalgae and seaweed, ripped off hard surfaces by waves and currents, take chunks of hard surface to other habitats.

How Fish Use Hard Bottom Habitat

How Fish Use Hard Bottom Habitat

Hard bottom habitats are often the only source of structure and refuge in open ocean waters. As such, hard bottom attracts a large number of fish. Young grouper, snapper, spadefish and black sea bass utilize hard bottom as nursery habitat while king mackerel, gag grouper and snapper forage on and above hard bottom areas. Hard bottom serves as a spawning area for black sea bass, grouper and damselfish. The structure of hard bottoms provides a refuge area for gag grouper and black sea bass.

Highly Associated Species

Highly Associated Species

  • Black Sea Bass
  • Various snapper species
  • Various grouper species
  • Mackerel
  • Spadefish
Threats to Hard Bottom Habitat

Threats to Hard Bottom Habitat

  • Dredging for beach nourishment directly removes hard bottom habitat
  • Damage from fishing gear, boat anchors and ocean dumping uproots coral and tears loose rocks
  • Offshore energy development can physically damage hard bottom
Important Facts about Hard Bottom Habitat

Important Facts about Hard Bottom Habitat

  • The coast of North Carolina is often called the “graveyard of the Atlantic” because of the numerous shipwrecks along the coastline. These wrecks now function as hard bottom habitat.
  • More than 90% of the hard bottom off North Carolina occurs south of Cape Lookout, some very close to shore.
  • This habitat is also called “live rock” because of the abundance of plants and invertebrates that attach and cover it.