In the ocean, habitat encompasses the whole environment from the seafloor to the surface of the water. Alaska’s frigid waters contain a remarkable diversity of ocean habitats including kelp forests, eelgrass meadows, deep-sea coral gardens, ocean valleys and seamounts, the summits of the ocean.
All are home to different types of sea life from whales to plankton. Commercially important fish and crabs require a wide variety of habitats at different stages of their lives.
We collect information on spawning and breeding grounds, nursery areas and feeding grounds. Working with private and public partners, our studies span the Gulf of Alaska, Aleutian Islands, Bering Sea, Chukchi Sea, Beaufort Sea and along the west coast of the U.S. We seek to learn more about what makes these places special for sustaining marine life.
Identifying Essential Fish Habitat in Alaska
One of NOAA Fisheries’ missions is to identify and describe Essential Fish Habitat. This involves mapping the location of physical, biological and chemical characteristics necessary for each stage of development for commercially managed fish species in Alaska. We must also assess the ecological value and condition of the habitat and monitor the natural and human activities that can impact it.
Abundance estimates from annual bottom trawl surveys are combined with environmental data to develop basin-wide habitat models for groundfish and crabs. Environmental conditions like ocean temperature, depth, current patterns and seafloor structure including structure forming invertebrates like deep-sea corals and sponges (Alaska bathymetry interactive maps) determine Essential Fish Habitat in the marine environment. Different seafloor types or sediments affect the distribution and abundance of key commercial species of Alaska groundfish including walleye pollock, Pacific cod, flatfish, sablefish, rockfish and commercially-important blue and red king crabs, tanner crab and snow crab.
Using sophisticated sonar technologies, towed cameras, remotely operated vehicles (ROVs), deep-sea manned submersibles, and, in some cases, scuba equipment we are able to identify the physical and biological characteristics of the seafloor from near-shore habitats to deeper waters.
We also use data collected by the National Ocean Service’s hydrographic surveys, smooth sheets, to learn more about the bottom types (e.g., sand, gravel), physical features (e.g., rocks, islets, kelp) and ocean depths (bathymetry) in Alaskan waters.
Data collected in the field and analyzed in the lab are fed into computer models. By comparing model results with what was actually seen in the field, we can test the accuracy of the models.
Prioritizing the Work: Habitat Assessments
Scientists conduct habitat assessments to understand the relationships between habitat characteristics, the productivity of fishery species, and the type and magnitude of various human impacts on the habitats. Given the enormity of the task for the Alaska region, which encompasses nearly 3-million-square-miles (from the Arctic to the coast of California), scientists must prioritize the fish habitats to be assessed.
