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A Field Guide to the Deepwater Sponges of the Aleutian Islands Archipelago

Project Goal

To compile detailed species descriptions for sponges collected in Alaska, principally in the central Aleutian Islands, in a guide. This guide will provide fisheries observers and scientists with the information necessary to adequately identify sponge fauna for the purpose of mapping areas of high abundance and determining the locations of indicator species of vulnerable marine ecosystems.

Geographic Location

North Pacific Ocean, Alaska

Approach

The sponges described in this guide are of those collected principally during two expeditions to the central Aleutian Islands in 2004 -- one aboard the RV Velero IV and the other aboard the RV Roger Revelle. A few additional sponge specimens were collected during the pioneering work in the region aboard the RV Velero IV in 2002 and 2003. Additionally we reviewed video footage of the seafloor filmed during 31 dives with the submersible Delta and 13 dives with the ROV Jason II. A total of approximately 127 km of seafloor habitat was examined (35 km and 92 km, respectively) for the presence of sponge fauna with particular focus on taxa included in this guide. Habitat information including depth, substrate, and associated fauna was recorded for sponge observations often made from multiple camera perspectives.

Results

The Guide to the Deep-Water Sponges of the Aleutian Island Archipelago contains detailed species descriptions for 112 sponges collected in Alaska, principally in the central Aleutian Islands. Each species description provides information on 1) typical growth form(s), 2) surface morphology including the presence and description of oscula, 3) consistency and texture, 4) known size range or dimensions, and 5) color in life and under various preservation methods. Detailed information on the skeletal structure of each species is provided for those who wish to definitively confirm specimen identification. The known zoogeographic range and information on the physical habitat and oceanographic habitat (i.e., temperature and salinity) of each species both within Alaskan waters and throughout its known range are also provided. Finally, for each species, special remarks with regard to taxonomic history, biology, and ecology are included. Appendix I provides a current and comprehensive taxonomic list of all sponges currently known to occur in the deep waters (>80 m) of Alaska. Appendix II provides a ranking for all the species included in this guide in terms of importance as fish habitat and vulnerability to disturbance from fishing activities. Appendix III includes a glossary of terms commonly used in the species descriptions. Appendix IV includes scanning electron microscopy (SEM) images of spicules from select calcareous, hexactinellid, and demosponges found in Alaskan waters.

Importance to Management

The main purpose of this guide is to promoting an awareness and appreciation of the importance of the sponge fauna in the North Pacific Ocean, particularly in the Aleutian Islands where the diversity and abundance of sponges appear to be extraordinary and where bycatch in existing fisheries continues to be a major concern for resource managers. Bycatch in fisheries and fisheries-independent surveys is a major source of information on the location of the sponge fauna and also a source of specimens for study. This guide serves the additional purpose of providing fisheries observers and scientists with the information necessary to adequately identify sponge fauna so that the data can be included in existing databases. These data can be used to map areas of high abundance and the locations of indicator species of vulnerable marine ecosystems. The guide is also designed for use by scientists making observations of the fauna in situ with submersibles including remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs).

Links

The Guide is now available at: http://spo.nmfs.noaa.gov/pp12.pdf

Fiscal Year 2009 Funding

$20,750

Point of Contact

Robert Stone, Bob.Stone@noaa.gov