Acoustic scattering from fish and euphausiids, FVs Frosti and Goldrush 2009

Metadata:

• Identification_Information
• Data_Quality_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Kelly Benoit-Bird

Publication_Date: Unpublished material

Title:

Acoustic scattering from fish and euphausiids, FVs Frosti and Goldrush 2009

Geospatial_Data_Presentation_Form: tabular digital data

Description:

Abstract:

The science efforts aboard the F/V Frosti and F/V Goldrush as part of the Patch Dynamics Study around the Pribilof Islands and Bogoslof Island, a component of the BEST/BSIERP Partnership Program, included basic hydrography, phytoplankton standing stock, zooplankton abundance, fish abundance, and fish proximate composition.

Purpose:

To quantify the forage base for fur seals and marine birds around the Pribilof Islands and Bogoslof Island in the Bering Sea.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20090718

Ending_Date: 20090812

Currentness_Reference: observed

Status:

Progress: Complete

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Description_of_Geographic_Extent:

200 km radius around St. Paul, Pribilof Islands stretched down to the Aleutian Islands to encompass Bogoslof Island, Alaska

Bounding_Coordinates:

West_Bounding_Coordinate: -173.34810

East_Bounding_Coordinate: -165.4006

North_Bounding_Coordinate: 58.8440

South_Bounding_Coordinate: 52.9105

Keywords:

Theme:

Theme_Keyword_Thesaurus: IOOS Core Variables

Theme_Keyword: Fish abundance

Theme_Keyword: Zooplankton abundance

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: Acoustic scattering

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: Pribilof Islands

Place_Keyword: Bogoslof Island

Place_Keyword: Bering Sea

Theme:

Theme_Keyword_Thesaurus: None

Theme_Keyword: project_number:B67

Theme_Keyword: data_url:<http://data.eol.ucar.edu/codiac/dss/id=245.B67-001>

Theme_Keyword: archive_url:<http://www.eol.ucar.edu/projects/bsierp>

Access_Constraints: None

Use_Constraints: Contact data author before using data in a publication.

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Kelly Benoit-Bird

Contact_Organization: Oregon State University

Contact_Address:

Address_Type: mailing

Address: 104 COAS Admin Bldg

City: Corvallis

State_or_Province: OR

Postal_Code: 97331

Contact_Voice_Telephone: 541-737-2063

Contact_Electronic_Mail_Address: kbenoit@coas.oregonstate.edu

Data_Quality_Information:

Logical_Consistency_Report: Unspecified

Completeness_Report: Unspecified

Lineage:

Methodology:

Methodology_Type: Field

Methodology_Description:

Data Set Overview: Underway acoustic backscatter strength separated into backscatter consistent with scattering from swimbladdered fish and scattering consistent with euphausiids.
Instrument Description: Simrad 200-7C, 120-7C, 70-7C, and 38-12 transducers were mounted on a rigid pole approximately 1 m below the surface off the port side of the F/V Frosti so that the centers of the transducers were no more than 10 cm apart. All echosounders were calibrated with a standard sphere technique using a hardware set up identical to that used during sampling. Acoustic data were logged nearly continuously during the period of 13 July – 7 August 2008. The 38 kHz echosounder has a 12 degree conical beam while the 70, 120, and 200 kHz echosounders each had 7 degree conical beams. Each echosounder used a 256 micros outgoing pulse.

Process_Step:

Process_Description:

Backscatter from 10 m below the surface to 0.5m from the sounder detected bottom in shallow water or to 200 m in deep water were analyzed. Volume scattering at 38 and 120 kHz was averaged over 5 m vertically by 5 echoes horizontally before subtracting the volume scattering at 38 kHz from that at 120 kHz to separate data into two acoustic categories, one attributed to swimbladdered fish and one to euphausiids based on the observed frequency response. Experience from our surveys as well as those conducted by NOAA surveys where organisms are sampled to verify the acoustic backscatter in the Bering Sea suggest that this is a reasonable generalizatio. Cells with a Sv120-Sv38 (Sv is a log10 unit of backscatter strength) in the range of –9.3 to 9.3 dB were assigned to the fish category and those in the range of 9.3 to 30 dB were assigned to the euphausiid category. Acoustic backscatter in these categories were averaged in 0.5 nmi elementary samplingdistance units (EDSU’s) in 5m depth cells along the vessel trackline. Backscatter in the "fish" category was integrated in 0.5 nmi horizontal by 5 m vertical bins at 38 kHz. Scattering in the "euphausiid" category was integrated in 0.5 nmi horizontal by 5 m vertical bins at 120 kHz using a -80 Sv integration threshold. Acoustic backscatter strength is given in sA with units of m2nmi-2 and is a linear measure of backscatter strength (see MacLennan et al, 2002 for a good discussion of acoustic units).
Data from each transect is in two files, one for 38 kHz backscatter strength consistent with fish and one for 120 kHz backscatter strength consistent with euphausiids.

Process_Date: Unknown

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: National Center for Atmospheric Research

Contact_Person: Earth Observing Laboratory

Contact_Address:

Address_Type: mailing and physical

Address: 3450 Mitchell Lane

City: Boulder

State_or_Province: CO

Postal_Code: 80301

Country: USA

Contact_Voice_Telephone: 303-497-8154

Contact_Electronic_Mail_Address: codiac@ucar.edu

Contact_Electronic_Mail_Address: stott@ucar.edu

Distribution_Liability:

No warranty expressed or implied is made regarding the accuracy or utility of the data, nor shall the act of distribution constitute such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with the data. The NCAR and NPRB shall not be held liable for improper or incorrect use of the data described and/or contained herein.

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Format_Name: SHP

File_Decompression_Technique: No compression applied

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Network_Resource_Name: <http://beringsea.eol.ucar.edu>

Fees: None

Metadata_Reference_Information:

Metadata_Date: 20090409

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: National Center for Atmospheric Research

Contact_Person: Earth Observing Laboratory

Contact_Address:

Address_Type: mailing and physical

Address: 3450 Mitchell Lane

City: Boulder

State_or_Province: CO

Postal_Code: 80301

Country: USA

Contact_Voice_Telephone: 303-497-8154

Contact_Electronic_Mail_Address: codiac@ucar.edu

Contact_Electronic_Mail_Address: stott@ucar.edu

Metadata_Standard_Name:

FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001.1-1999