Mid-Depth Rocky Ecosystems (30-100 meters)

 

AMIDST ROCKS, COMES LIFE

Mid-depth rocky ecosystems occur where rock formations lie beneath 30 to 100 meters of water depth, These rocky outcrops and pinnacles are home to a rich diversity of life, that includes hundreds of fish species and invertebrates. For decades, these habitats have supported important fishery stocks, including shelf rockfish and lingcod.

 

A RICH TAPESTRY OF LIFE

Uniquely shaped by the reduced light levels, this mid-depth ecosystem is not typically characterized by large kelp life and photosynthetic algae. Instead, much of the habitat is made up of sessile invertebrates including plumose anemones, structure-forming sponges, and hydrocorals. These organisms serve the important purpose of creating and structuring habitat for other, more mobile, species like rock crabs, sheep crabs, basket stars, and sea stars. Piscivorous fish like yelloweye rockfish, copper rockfish, starry rockfish, and lingcod are key predators on these reefs.

 

A DELICATE SYSTEM

The majority of the species dwelling in mid-depth rocky ecosystems are long-living organisms, reaching maturity at a later age. These include rockfishes and other predatory fishes that are both ecologically and economically important species. Given their lifecycle, the majority of species in this ecosystem are expected to show only slow population growth following MPA implementation. On an even greater extreme, key habitat-forming species, like hydrocorals, are very slow-growing, fragile, and susceptible to the direct physical damage that can occur with fishing gear that makes contact with the seafloor...