ShoreZone Habitats in Alaska, British Columbia and Washington

An important element of the ShoreZone habitat mapping system is the classification of habitat for each segment of the shoreline, where habitat is defined as the combination of substrate and energy. Substrate is considered in terms of three general categories: stable substrates, which usually support rich epibenthic biotic communities, mobile substrates that are dynamic and limit epibenthos and partially mobile substrates where there is a combination of mobile and stable substrate. Most of the energy on the shoreline is derived from wave exposure and six levels of wave energy are cataloged. However, at some locations current energy from tidal currents or river current may structure the habitat present. The ShoreZone system records one of over 40 possible habitat classes of substrate and energy for each shoreline segment. There is a “typical” association of biota associated with each of these habitat classes. Biota may not always be observed on the shoreline due to a variety of factors (e.g., season, accidents of recruitment, visibility in the imagery) but the habitat class does provide an indication of habitat suitability for various benthic organisms. This makes the habitat class a very powerful modeling and mapping tool. Occurrence of biota as biobands associated with the most common habitat classes will be presented, as well as implications of those associations for modeling nearshore fish habitats at local and regional scales. For example, in comparing the southwest to the southeast coast of Baranof Island, south of Sitka Alaska, of the 1460 km of shoreline on the southwest, exposed side of the island, approximately 340 km of shoreline (23%) is classified as the ‘semi-protected, partially mobile’ habitat class. Dominant nearshore canopy kelp biobands are Giant Kelp and Bull Kelp. On the 372 km on the adjacent southeast end of Baranof Island which is more sheltered and has a less crenulated shoreline, 103 km is classified as habitat class ‘semi-protected, partially mobile’ (28%) and the dominant canopy kelps are Dragon Kelp and Bull Kelp.