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Physical Location
Data Set Info
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Access Info
Distribution Info
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Data Quality
Data Management
Lineage
Child Items
Catalog Details

Summary

Short Citation
Alaska Fisheries Science Center, 2024: AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (weight/hectare), https://www.fisheries.noaa.gov/inport/item/28210.
Full Citation Examples

Abstract

The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996.

Distribution Information

  • Data bundled in 32318 parent project archive including:

    28202-AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects-1996-Other

    28204-AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Bottom Trawl Catch Effort Data from NORPAC for Years 1973-2001

    28208-AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (count/hectare)

    28210-AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (weight/hectare) ---

Access Constraints:

None

Use Constraints:

The United States Government shall not be held liable for improper or incorrect use of data described and/or contained herein. These data and related graphics are not legal documents and are not intended to be used as such. The Alaska Fisheries Science Center gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. Spatial information may not meet National Map Accuracy Standards. The information contained in these data is dynamic and may change over time. Original data were compiled from various sources. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and consistent within the limitations of geospatial data in general and these data in particular. It is strongly recommended that these data are directly acquired from an Alaska Fisheries Science Center server and not indirectly through other sources which may have changed the data in some way. Although these data have been used (processed) successfully on a computer system at the Alaska Fisheries Science Center, no warranty expressed or implied is made regarding the utility of the data on another system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data.

Child Items

Type Title
Entity wcpue_1996_tows

Contact Information

Point of Contact
Bob McConnaughey
bob.mcconnaughey@noaa.gov

Metadata Contact
Steve Intelmann
steve.intelmann@noaa.gov
(206) 526-4157

Extents

Geographic Area 1

-162.455799° W, -159.664745° E, 58.07317° N, 56.101181° S

Time Frame 1
1996 - 1997

Item Identification

Title: AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (weight/hectare)
Short Name: AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (weight/hectare)
Abstract:

The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996.

Purpose:

Benthic communities are structured by dynamically interacting factors that determine habitat quality. Since benthic macrofauna demonstrate strong and often narrowly defined affinities, forces altering (or disturbing) the environment will be of considerable importance to their distribution and abundance. Commercial fishing with mobile gear, such as bottom trawls and dredges, and the physical disturbance that results, is widespread in continental shelf areas. Because of its prevalence and the potential for adverse effects, there have been numerous attempts to quantify sea-floor exposure at various spatial scales. The well documented development of commerical fisheries in the eastern Bering Sea (EBS) since 1954 presents a unique opportunity for studying trawling impacts. The Crab and Halibut Protection Zone 1 (CHPZ1; also known as management area 512), located north of the Alaska Peninsula in Bristol Bay, has a long and complex history of trawl prohibitions that extend from 1959 to the present. Using detailed accounts of closures and fishing activity, it is possible to reconstruct historical effort and identify essentially pristine areas immediately adjacent to areas that have been heavily fished with bottom trawls. This physical arrangement permits an examination of chronic disturbance by bottom trawls, without confounding environmental effects that result from geographic separation. Sampling locations were preselected on the basis of historical fish effort. Starting positions for commercial bottom trawls (n=392 743 through July 1996) were spatially joined with a 1 nm2 grid to calculate total number of trawls per nm2, and thus identify heavily fished (HF) and unfished (UF) areas along the boundary of the CHPZ1 (NORPAC fishery observer database maintained at the NMFS Alaska Fisheries ScienceCenter, Seattle, Washington). HF and UF cells on opposite sides of the boundary line were paired a priori on the basis of spatial proximity and were generally separated by 1 nm to allow for prior navigational discrepancies. A total of 42 pairs was identified at the northeastern corner of the CHPZ1. Catch data were spatially joined to line segments which were created from the start and ending trawl positions for each haul.

Notes:

Loaded by FGDC Metadata Uploader, batch 7447, 10-27-2015 16:56

The following FGDC sections are not currently supported in InPort, but were preserved and will be included in the FGDC export:

- Spatial Reference Information (FGDC:spref),

- Spatial Data Organization Information (FGDC:spdoinfo)

Supplemental Information:

Effects of Chronic Bottom Trawling on the Size Structure of Soft-Bottom Benthic Invertebrates. American Fisheries Society Symposium 41:425?437, 2005

Keywords

Theme Keywords

Thesaurus Keyword
UNCONTROLLED
None Bottom Trawling
None Invertebrates
None Macrofauna

Spatial Keywords

Thesaurus Keyword
UNCONTROLLED
None Bering Sea

Physical Location

Organization: Alaska Fisheries Science Center
City: Seattle
State/Province: WA
Country: USA

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: None Planned
Data Presentation Form: Map (digital)

Support Roles

Data Steward

CC ID: 247766
Date Effective From: 2015
Date Effective To:
Contact (Person): McConnaughey, Bob
Email Address: bob.mcconnaughey@noaa.gov

Distributor

CC ID: 247767
Date Effective From: 2015
Date Effective To:
Contact (Organization): Alaska Fisheries Science Center (AFSC)
Address: 7600 Sand Point Way N.E., Building 4
Seattle, WA 98115
USA
Email Address: afsc.webmaster@noaa.gov
Phone: (206) 526-4000
Fax: (206) 526-4004
URL: https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
Business Hours: 0700-1700 Pacific Time

Metadata Contact

CC ID: 237292
Date Effective From: 2015-10-27
Date Effective To:
Contact (Person): Intelmann, Steve
Address: 7600 Sand Point Way N.E., Building 4
Seattle, WA 98115
USA
Email Address: steve.intelmann@noaa.gov
Phone: (206) 526-4157
Fax: (206) 526-6723

Point of Contact

CC ID: 237293
Date Effective From: 2015-10-27
Date Effective To:
Contact (Person): McConnaughey, Bob
Email Address: bob.mcconnaughey@noaa.gov

Extents

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 237291
W° Bound: -162.455799
E° Bound: -159.664745
N° Bound: 58.07317
S° Bound: 56.101181

Extent Group 1 / Time Frame 1

CC ID: 248467
Time Frame Type: Range
Start: 1996
End: 1997

Access Information

Security Class: Unclassified
Data Access Procedure:

unknown

Data Access Constraints:

None

Data Use Constraints:

The United States Government shall not be held liable for improper or incorrect use of data described and/or contained herein. These data and related graphics are not legal documents and are not intended to be used as such. The Alaska Fisheries Science Center gives no warranty, expressed or implied, as to the accuracy, reliability, or completeness of these data. Spatial information may not meet National Map Accuracy Standards. The information contained in these data is dynamic and may change over time. Original data were compiled from various sources. The data are not better than the original sources from which they were derived. It is the responsibility of the data user to use the data appropriately and consistent within the limitations of geospatial data in general and these data in particular. It is strongly recommended that these data are directly acquired from an Alaska Fisheries Science Center server and not indirectly through other sources which may have changed the data in some way. Although these data have been used (processed) successfully on a computer system at the Alaska Fisheries Science Center, no warranty expressed or implied is made regarding the utility of the data on another system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data.

Distribution Information

Distribution 1

CC ID: 247768
Download URL: https://access.afsc.noaa.gov/data-zips/32318_GAP_1996_Trawlex_chronic-effects-other.zip
Distributor:
Description:

Data bundled in 32318 parent project archive including:

28202-AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects-1996-Other

28204-AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Bottom Trawl Catch Effort Data from NORPAC for Years 1973-2001

28208-AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (count/hectare)

28210-AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (weight/hectare) ---

File Type (Deprecated): Zip
Compression: Zip

Technical Environment

Description:

Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.3.0.4322

Data Quality

Quality Control Procedures Employed:

see Process Steps

Data Management

Have Resources for Management of these Data Been Identified?: No
Approximate Percentage of Budget for these Data Devoted to Data Management: Unknown
Do these Data Comply with the Data Access Directive?: No
Is Access to the Data Limited Based on an Approved Waiver?: No
If Distributor (Data Hosting Service) is Needed, Please Indicate: Yes
Approximate Delay Between Data Collection and Dissemination: Unknown
Actual or Planned Long-Term Data Archive Location: NCEI-MD
Approximate Delay Between Data Collection and Archiving: unknown
How Will the Data Be Protected from Accidental or Malicious Modification or Deletion Prior to Receipt by the Archive?:

IT Security and Contingency Plan for the system establishes procedures and applies to the functions, operations, and resources necessary to recover and restore data as hosted in the Western Regional Support Center in Seattle, Washington, following a disruption.

Lineage

Process Steps

Process Step 1

CC ID: 237296
Description:

Macrofauna sampling was conducted aboard two identical 40 m chartered stern trawlers, the sister ships FV ??Aldebaran?? and FV ??Arcturus??. Each is powered by a 1525 hp main engine and fitted with a variable pitch propeller and propeller nozzle. Macrofauna were sampled with identical 83?112 eastern otter trawls, selected to ensure relatively large samples of patchily distributed organisms and to minimize clogging of the opening by large macrofauna (e.g. sea stars). These nets have a 25.3 m headrope and a 34.1 m footrope and have been the standard sampling gear used for annual NMFS groundfish-crab surveys in the EBS since 1982. The trawl was towed behind 1000 kg steel V-doors and 54.9 m paired dandylines. Each lower dandyline has a 0.61 m chain extension connected to the lower wing edge to improve bottom-tending characteristics. For this study, the standard trawl was modified to improve catchability and retention of macrofauna. It was equipped with a tickler chain and a hula skirt, and had a 3.8 cm liner covering both wings and the entire bottom body, with complete coverage top and bottom of the intermediate and codend. An acoustic net mensuration system and a mechanical bottom contact sensor were used to assess net configuration and collect performance data for area-swept and catch-per-uniteffort (c.p.u.e.) calculations. Each vessel sampled adjoining HF-UF stations (??pairs??) by towing the trawl through the centre of a 1 nm2 cell for 1.39 km (i.e., 3 knots for 15 min). Catches were fully processed in the field by sorting macrofauna to the lowest possible taxon and then weighed and enumerated separately. Weights were determined using a motion-compensated precision electronic balance. Biogenic substrate, such as empty gastropod and bivalve shells, and identifiable egg masses were also weighed, so as to provide a more complete characterization of the benthos. Prior to analysis, catch data were lumped into larger taxonomic groups to resolve classification differences between the vessels and to reduce the number of dependent variables. Bottom trawl catches (CPUE)are standardized according to area swept, as determined with Scanmar ascoustic system and GPS coordinates of vessel. Catch values are weights of organisms/hectare.

Process Step 2

CC ID: 237297
Description:

Data were entered into a spreadsheet and converted to point features in ArcGIS.

Process Step 3

CC ID: 237298
Description:

Point features were converted to line features based on feature and vertex ID to represent the starting and ending locations of each trawl deployment. Catch and other environmental data, such as depth and temperature, were then spatially joined to each line segment based on a key field identifier from the original data.

Process Date/Time: 1996-08-01 00:00:00

Child Items

Rubric scores updated every 15m

Rubric Score Type Title
Entity wcpue_1996_tows

Catalog Details

Catalog Item ID: 28210
GUID: gov.noaa.nmfs.inport:28210
Metadata Record Created By: Nancy Roberson
Metadata Record Created: 2015-10-27 16:56+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2024-01-15 12:08+0000
Metadata Record Published: 2019-05-31
Owner Org: AFSC
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2019-05-31
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2020-05-31