Acoustic scattering from fish and euphausiids, Frosti 2008

Acoustic scattering from fish and euphausiids, Frosti 2008

Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: Kelly Benoit-Bird
Publication_Date: Unpublished material
Title: Acoustic scattering from fish and euphausiids, Frosti 2008
Geospatial_Data_Presentation_Form:
Description:
Abstract:
The science efforts aboard the F/V Frosti as part of the Patch Dynamics Study around the Pribilof Islands, 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 in the Bering Sea.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20080713
Ending_Date: 20080807
Currentness_Reference: observed
Status:
Progress:
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Description_of_Geographic_Extent: 200 km radius around St. Paul, Pribilof Islands, Alaska
Bounding_Coordinates:
West_Bounding_Coordinate: -173.34810
East_Bounding_Coordinate: -167.18750
North_Bounding_Coordinate: 58.8440
South_Bounding_Coordinate: 55.4048
Keywords:
Theme:
Theme_Keyword_Thesaurus: IOOS Core Variables
Theme_Keyword: Version 1
Theme_Keyword: Fish abundance
Theme_Keyword: Zooplankton abundance
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: Acoustic scattering
Theme:
Theme_Keyword_Thesaurus: AOOS Data Services
Theme_Keyword: metadata=NPRB/BSIERP/B67_Benoit-Bird_Acoustic.xml
Theme:
Theme_Keyword_Thesaurus: Alaska Marine Information System
Theme_Keyword: project_number:unknown
Theme_Keyword:
data_url:<http://ak.aoos.org/data/bsierp/secure/B67/Benoit-Bird/acoustic/>
Place:
Place_Keyword_Thesaurus: None
Place_Keyword: Pribilof Islands
Place_Keyword: Bering Sea
Access_Constraints:
Access is restricted. Data policy: <http://bsierp.nprb.org/posted/proj_mgmt/Final%20NPRB-NSF%20program%20management%20plan%202007%2012_21.pdf>
Use_Constraints:
Use is restricted. (1) Contact data author before using data in a publication. (2) Data policy: <http://bsierp.nprb.org/posted/proj_mgmt/Final%20NPRB-NSF%20program%20management%20plan%202007%2012_21.pdf>
Data_Quality_Information:
Logical_Consistency_Report:
Completeness_Report:
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
Process_Step:
Process_Description:
Updated metadata record to link with Alaska Marine Information System. Original filename: At Sea PDS Acoustic Data Metafile 2008.xml New filename: B67_Benoit-Bird_Acoustic.xml
Process_Date: 20091026
Metadata_Reference_Information:
Metadata_Date: 20090409
Metadata_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
Metadata_Standard_Name:
FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001.1-1999
Generated by mp version 2.9.7 on Wed Oct 28 11:18:12 2009