Project Description

Deep-sea coral and sponge ecosystems are widespread throughout most of Alaska's marine waters. They are vulnerable to the effects of commercial fishing activities and are potentially impacted by climate change and ocean acidification. Because of the size and scope of Alaska's continental shelf and slope, the vast majority of the area has not been surveyed for deep-sea coral and sponge abundance. The goal of the Alaska Deep Sea Coral and Sponge Initiative (AKCSI) is to better understand the location, distribution, ecosystem role, and status of deep-sea coral and sponge habitats. There are 10 projects. Geologists Jennifer Reynolds and Gary Greene are collaborating with other AKCSI researchers to construct interpreted (from geology) substrate and potential habitat maps for deep-sea corals and sponges in Gulf of Alaska and Aleutian Islands waters. While other habitat characteristics also come into play, the distribution of deep-sea corals and sponges is strongly tied to substrate characteristics. The geology and oceanography of the seabed control the distribution of substrates and can be used to construct potential habitat maps for these species. These maps may be combined with other types of information, e.g., bycatch in bottom trawls, for predictive modeling of species distribution (Chris Rooper). The potential habitat maps will be based on bathymetry, sonar and sediment data; on ground truth from available seafloor video and still photo imagery; and on geological interpretation that takes into account the bedrock and tectonic patterns, sediment type and thickness, oceanography, and seafloor morphology. Project 1: Primnoa Habitat Areas in the Gulf of Alaska. The species of interest is the red tree coral Primnoa pacifica, the dominant structure-forming coral on the continental shelf of the Gulf of Alaska. This project will verify and characterize the locations of red tree coral thickets as indicated in bycatch rates from the annual NMFS sablefish stock assessment survey (Bob Stone). In 2012, Fugro Pelagos, Inc. conducted multibeam bathymetric and backscatter mapping of four study sites in the central and southeastern Gulf of Alaska. These were sites where NOAA longline survey bycatch of Primnoa coral suggested the presence of large Primnoa colonies. Studying these sites will help us identify optimal habitat, predict other sites based on the geology and oceanography, and provide a basis for understanding how Primnoa habitat associations vary with depth, latitude, substrate, and other major oceanographic factors. The sites were mapped at 110 kHz and 100% coverage to ~800 m depth. In 2013, maps of potential habitat for deep-sea corals and sponges were constructed from the bathymetry and backscatter data (Reynolds and Greene). Locations for exploration and ground truthing were identified and surveyed with an ROV during fieldwork in 2013. Other AKCSI projects also used these ROV dives to deploy settlement plates in Primnoa thickets, survey the size distribution of Primnoa aggregates, and collect Primnoa and other deep sea coral and sponge specimens for genetic analysis, growth rate and geochemical studies (Bob Stone, Peter Etnoyer, Cheryl Morrison). A second ROV cruise is planned for 2015 to complete the seafloor surveys and sampling. Project 10: Geological substrate and potential habitat map for deep sea corals and sponges in the Gulf of Alaska margin and the Aleutian shelf and slope regions. Targeted sites in the Alaska region have been surveyed and high-resolution maps of potential habitat (substrate) have been constructed. These maps have contributed to our understanding of ecological patterns. However, at a regional scale this data compilation and interpretation has not been done. This project will prepare interpreted regional seafloor substrate and potential habitat maps that cover the shelf and slope of the Gulf of Alaska and Aleutians (Reynolds and Greene). Due to data limitations and the large area to be covered, these maps will be constructed from archived data at relatively low resolution (1-5km). High-resolution surveys at specific sites in these regions will form the basis for interpreting seafloor patterns in the broader areas.

Project Funding

NOAA's Deep Sea Coral Research and Technology Program
Start Date: 2012-06-00 End Date: 2016-06-00

 

 

 

Research Team