28202
AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects-1996-Other
AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects-1996- Other
Data Set
Published / External
32318
AFSC/RACE/GAP/McConnaughey:Trawlex chronic effects-1996-Other
Project
2000-01-01
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. Catch data were extracted from the AFSC NORPAC database for years 1973-2001 to provide a summary of trawl catch effort, specific focus was placed on the area within Fisheries Management Area 512. Data were merged with a 1nm grid that covered fisheries management area 512. The total number of hauls were summed for all points falling within each 1nm cell.
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 extracted from the AFSC NORPAC database for years 1973-2001 to provide a summary of trawl catch effort.
Loaded by FGDC Metadata Uploader, batch 7442, 10-27-2015 16:51
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)
Effects of Chronic Bottom Trawling on the Size Structure of Soft-Bottom Benthic Invertebrates. American Fisheries Society Symposium 41:425?437, 2005
Theme
Bottom trawling
Alaska Fisheries Science Center
Seattle
WA
USA
Data Set
None Planned
Map (digital)
See access and use constraints information.
N/A
N/A
N/A
28203
bottomtrawl_alleffort_grid
bottomtrawl_alleffort_grid
Published / External
Loaded by FGDC Metadata Uploader, batch 7442, 10-27-2015 16:51
OBJECTID_1
Unknown
No
No
Active
Internal feature number.
Sequential unique whole numbers that are automatically generated.
Shape
Unknown
No
No
Active
Feature geometry.
Coordinates defining the features.
LONGDD_GRI
Unknown
No
No
Active
Longitude Decimal Degrees of grid cell center
LATDD_GRID
Unknown
No
No
Active
Latitude Decimal Degrees of grid cell center
PAIR
Unknown
No
No
Active
Unique number assigned to HF/UF sample pair, based on proximity to CHPZ1.
Shape_Leng
Unknown
No
No
Active
Sum_NTOWS
Unknown
No
No
Active
Summation of total number of tows (NTOWS) within a 1nm square grid cell, independent of year.
Shape_Length
Unknown
No
No
Active
Length of feature in internal units.
Positive real numbers that are automatically generated.
Shape_Area
Unknown
No
No
Active
Area of feature in internal units squared.
Positive real numbers that are automatically generated.
Data Steward
2015
Person
McConnaughey, Bob
bob.mcconnaughey@noaa.gov
Distributor
2015
Organization
Alaska Fisheries Science Center
AFSC
afsc.webmaster@noaa.gov
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
(206) 526-4000
(206) 526-4004
https://www.fisheries.noaa.gov/about/alaska-fisheries-science-center
AKFSC Home Page
Online Resource
0700-1700 Pacific Time
Metadata Contact
2015-10-27
Person
Intelmann, Steve
steve.intelmann@noaa.gov
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
(206) 526-4157
(206) 526-6723
Point of Contact
2015-10-27
Person
McConnaughey, Bob
bob.mcconnaughey@noaa.gov
-163.866919
-158.670692
59.056487
55.468882
Range
1996
1997
Unclassified
unknown
None
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.
Personal GeoDatabase Feature C
ESRI Personal Geodatabase
https://access.afsc.noaa.gov/data-zips/32318_GAP_1996_Trawlex_chronic-effects-other.zip
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) ---
Zip
Zip
Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.3.0.4322
See Purpose
No
Unknown
No
No
Yes
Unknown
NCEI-MD
unknown
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.
1
Historical trawl catch data were retrieved from the NORPAC database and converted to a separate point feature.
2
The trawl effort point file was spatially joined with the 1 nm square lattice
3
The number of NTOWS (see metadata for bottomtrawl_allefort_pts) were summed for each 1nm cell.
4
A 1 square nautical mile lattice was created
1997-01-10T00:00:00
28204
Data Set
AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Bottom Trawl Catch Effort Data from NORPAC for Years 1973-2001
28208
Data Set
AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (count/hectare)
28210
Data Set
AFSC/RACE/GAP/McConnaughey: Trawlex Chronic Effects: Trawlex (1996) Macrofauna CPUE (weight/hectare)
28203
Entity
bottomtrawl_alleffort_grid
gov.noaa.nmfs.inport:28202
Nancy Roberson
2015-10-27T16:51:57
SysAdmin InPortAdmin
2024-01-15T12:08:04
2019-05-31
Alaska Fisheries Science Center
AFSC
7600 Sand Point Way N.E., Building 4
Seattle
WA
98115
USA
http://www.afsc.noaa.gov
0700-1700 Pacific Time
1001
Public
No
2019-05-31
1 Year
2020-05-31
Vector
GT-polygon composed of chains
18881
NAD 1983 Alaska Albers
55.0
65.0
-154.0
50.0
0.0
0.0
coordinate pair
0.0001
0.0001
meter
D North American 1983
GRS 1980
6378137.0
298.257222101
bottomtrawl_alleffort_grid
OBJECTID_1
Internal feature number.
ESRI
Sequential unique whole numbers that are automatically generated.
Shape
Feature geometry.
ESRI
Coordinates defining the features.
LONGDD_GRI
Longitude Decimal Degrees of grid cell center
LATDD_GRID
Latitude Decimal Degrees of grid cell center
PAIR
Unique number assigned to HF/UF sample pair, based on proximity to CHPZ1.
If grid cell was within the Crab and Halibut Protection Zone (CHPZ1) then sample was given a HF (highly fished) status. Likewise, if they fell outside of the CHPZ1 then they were given a UF (Unfished) status.
Shape_Leng
Sum_NTOWS
Summation of total number of tows (NTOWS) within a 1nm square grid cell, independent of year.
Value provides indicaton of fishing activity within a particular cell. 0-3=Low; 3-9=Medium; 9-19=High; and 19-57=Very High
Shape_Length
Length of feature in internal units.
ESRI
Positive real numbers that are automatically generated.
Shape_Area
Area of feature in internal units squared.
ESRI
Positive real numbers that are automatically generated.