New Study Highlights Importance of Deep-Sea Habitats to California's Commercial Fisheries

January 14, 2026

Cold-water corals and sponges create complex and vibrant habitats on the deep seafloor. These structure-forming animals thrive in cold, dark waters far below the ocean's surface, supporting diverse marine communities. Despite their well-known ecological importance, deep-sea coral and sponge ecosystems are one of the least studied habitats in U.S. waters due to their depth, wide distribution, and remoteness.

a brown speckled fish with big lips rests in a deep-sea orange coral — A lingcod, a commercially targeted species in California, rests atop a cold-water coral. Photo: CDFW/Marine Applied Research and Exploration.

All six of NOAA's national marine sanctuaries along the U.S. West Coast include and protect cold-water coral and sponge habitats. Understanding how these deep-sea ecosystems support marine life and coastal communities is a growing priority for NOAA, especially as offshore activities expand into deeper waters. Researchers at Channel Islands National Marine Sanctuary in California have been at the forefront of advancing these efforts with support from NOAA's Deep Sea Coral Research and Technology Program.

In a newly released publication in the journal Fish and Fisheries, researchers from the California Marine Sanctuary Foundation, Channel Islands National Marine Sanctuary, and NOAA's Southwest Fisheries Science Center found that about 30% of California's commercially-landed species are associated with cold-water coral and sponge habitats (e.g., bronzespotted rockfish (Sebastes gilli); lingcod (Ophiodon elongatus); California king crab (Paralithodes californiensis)).

They also found that commercially-targeted fish species were more likely to have documented associations than invertebrates, reflecting both ecological differences in fish and invertebrate species as well as limited life-history information on many deep-sea invertebrates. Overall, these findings demonstrate broad co-occurrence between commercially-important species and living deep-sea habitats, highlighting the importance of cold-water corals and sponges to California's fisheries.

a yellow and brown fish rests in a large, white deep-sea sponge — Quillback rockfish, a commercially targeted species in California, are commonly found sitting inside of large sponges. Photo: CDFW/Marine Applied Research and Exploration.

An Advancement in Sanctuary Science

For NOAA's Office of National Marine Sanctuaries, these findings underscore the relevance of deep-sea habitats to both ecosystem health and coastal communities that rely on fisheries. Deep-sea coral and sponge ecosystems dominate sanctuary seafloor areas on the West Coast, yet they remain some of the most challenging environments to study.

By linking fisheries landings data with ecological observations, this collaborative research advances sanctuary science and helps inform future monitoring, management, and conservation efforts. As emerging offshore activities expand into deeper waters, understanding how deep-sea habitats support commercially valuable species will be increasingly important for ecosystem-based management across the sanctuary system.