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Short Citation:
Northeast Fisheries Science Center, 2023: Gulf of Maine Cooperative Bottom Longline Survey Database,

Item Identification

Title: Gulf of Maine Cooperative Bottom Longline Survey Database
Short Name: Cooperative Bottom Longline Survey Database
Status: Completed

This database is for a bottom longline (fixed gear) survey executed in the western and central Gulf of Maine targeting complex rocky habitats. The survey is operated from collaborating commercial fishing vessels, and deploys 1 nm sets of traditional 'tub trawl' bottom longline groundfish gear (1000 hooks). Longline gear is deployed at randomly selected stations within selected NEFSC bottom trawl survey (BTS) strata in the western and central Gulf of Maine during the spring and autumn, overlapping temporally with the NEFSC seasonal BTS in that region. Specific ‘hard’ and ‘smooth’ bottom sub-strata were chosen within the BTS strata based on predictive habitat maps that have identified complex habitat at a spatial resolution of @1.3km2 (Manderson et al. 2011). The total number of longline stations are allocated by the overall area of each stratum, as done in the NEFSC BTS, and stations randomly distributed in the ‘hard’ and ‘smooth’ sub-stratum within each stratum. Each set is made for 2 hours, with gear deployed 1 hour prior to the estimated time for slack tide at that location. The ambient current is monitored with an instrument with an accelerometer (also equipped with a compass and thermometer), which is attached to the mainline on each end of the longline (by the last hook). Temperature-depth probes are deployed on the anchor at each end of the longline. Catch weights, fish lengths, and other biological data are collected for all species following standard survey protocols. Biological sampling (for age and reproductive data) is collected for a subset of species and sizes relative to the BTS’s request protocols to fill in data on uncommon species, and less common sizes (i.e. larger individuals) of key groundfish.

The objective of this survey is to provide important information for several species that are not well sampled in BTS or those that are not caught in substantive numbers (targeted) by commercial or recreational fisheries to inform management, Endangered Species Act (ESA) listing decisions, and conservation plan measures. These include cusk, which is a candidate species under the ESA and a data poor stock, as well as Atlantic Wolffish, Atlantic Halibut, and Thorny Skate, which are all NOAA Species of Concern. This survey is designed to increase sampling opportunities for all of these species. Catch and biological data from this survey provides useful supplemental data and indices for other groundfish including white hake, barndoor skate, red hake, spiny dogfish, haddock, Atlantic cod, and smooth skate.


A bottom longline (fixed gear) survey executed in the western and central Gulf of Maine focused on areas of complex rocky habitat that are not readily sampled by mobile trawl gear. This survey addresses concerns about the limited data of specific species in hard bottom habitats for important groundfish stocks collected on other surveys. It particularly enhances data collection for several data poor and depleted stocks that are specifically associated with rocky habitat.


Theme Keywords

Thesaurus Keyword
None bottom longline
None cooperative research
None data poor species
None fishery independent
None fixed gear
None groundfish
None survey

Temporal Keywords

Thesaurus Keyword
None biannual
None fall
None spring

Spatial Keywords

Thesaurus Keyword
None Cashes Ledge
None Fippennies Ledge
None Gulf of Maine
None hard bottom
None Jeffreys Ledge
None ledges
None Platts Bank
None rocky habitat
None Stellwagen Bank

Stratum Keywords

Thesaurus Keyword
None 0126
None 0127
None 0128
None 0129
None 0136
None 0137
None bottom trawl survey strata
None offshore strata

Physical Location

Organization: NEFSC Woods Hole Lab
City: Woods Hole
State/Province: MA
Country: USA

Data Set Information

Data Set Scope Code: Data Set
Data Set Type: Oracle Database
Maintenance Frequency: Continually
Data Presentation Form: Table (digital)

Support Roles

Data Steward

CC ID: 229326
Date Effective From: 2014-04
Date Effective To:
Contact (Person): McElroy, W. David
Address: 166 Water Street
Woods Hole, MA 02543-1026
Email Address:
Phone: 508-495-2249
Fax: 508-495-2258


CC ID: 229329
Date Effective From: 2014
Date Effective To:
Contact (Organization): Northeast Fisheries Science Center (NEFSC)
Address: 166 Water Street
Woods Hole, MA 02543-1026
Phone: (508)495-2000
Business Hours: 8:00 a.m. to 4:30 p.m. Monday - Friday

Metadata Contact

CC ID: 229328
Date Effective From: 2015-10
Date Effective To:
Contact (Person): McElroy, W. David
Address: 166 Water Street
Woods Hole, MA 02543-1026
Email Address:
Phone: 508-495-2249
Fax: 508-495-2258

Point of Contact

CC ID: 229327
Date Effective From: 2016
Date Effective To:
Contact (Person): Gervelis, Brian J
Address: 28 Tarzwell Drive
Narragansett, RI 02882
Email Address:
Phone: 401-782-3337
Fax: 401-782-3292

Point of Contact

CC ID: 229325
Date Effective From: 2014-04
Date Effective To:
Contact (Person): McElroy, W. David
Address: 166 Water Street
Woods Hole, MA 02543-1026
Email Address:
Phone: 508-495-2249
Fax: 508-495-2258
View Historical Support Roles


Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 229393
W° Bound: -70.5602
E° Bound: -67.60223
N° Bound: 43.27977
S° Bound: 42.09656

Central and western Gulf of Maine in U.S. territorial waters. Bottom trawl survey offshore strata: 0126, 0127, 0128, 0129, 0136, 0137

Extent Group 1 / Time Frame 1

CC ID: 229394
Time Frame Type: Continuing
Start: 2014-04

Biannual survey (spring & fall) conducted in 2014-2015. Survey is conducted in April/May and Oct/November in conjuction with the BTS leg 4. In spring 2014 a vessel breakdown resulted in survey completetion in the first few days of June.

Access Information

Security Class: Unclassified
Data Access Procedure:

NEFSC Data Access Procedure:

1. Formal request in writing usually to the data owner/contact or Center Director;

2. Requester is contacted by data owner to review and verify the request content and details for data delivery options.

3. If data is confidential then owner will determine if the data may be released to the requester;

4. If data can be released, the data is downloaded and packaged for delivery electronically; or the requester may be directed to where the data is available online.

Data Access Constraints:

NEFSC Data Access Constraint:

If data is stored on an internal NEFSC network, the requester may not have direct access to query the data unless they are also authorized for network access.

Distribution Information

Distribution 1

CC ID: 247346
Download URL:

7 data files:








Data extracted on 1/25/2018

Technical Environment


Vessel locations, fishing operational data, and aggregate fish weight data are recorded using the FLDRS v3.1 software. Aggregate fish weights are initially recorded on data sheets, and subsequently summed in excel and entered into FLDRS software. Fish length data are captured from wireless measuring boards on handheld Allegro field PC's with windows mobile using CEWedge software. The length data are recorded with DataTrawler v1.0 software written in visual basic, which outputs the data in a Microsoft access database file (.accdb). Biological data are recorded by hand and entered on shore into excel before loading into the Oracle database. Star Oddi temperature-depth sensors are downloaded using the Sea Star software v7.02 and exported in a .dat file.

Data Quality


Vessel locations are taken from the vessel's GPS and recorded at ±0.0001°. Fish weights are taken using Merel motion compensated scales, and recorded ±0.1 kg for aggregate catch weights and ±0.01 kg for individual fish weights. Aggregate fish weights are for undifferentiated sexes for all species, except spiny dogfish weights are sex specific. Fish lengths are collected using Latitude 42 boards with Haglof wireless sensors, and they are recorded at ±1 cm precision. Temperature and depth data at the anchors are recorded with Star Oddi sensors with a precision of ±0.01m and ±0.01°C. Current flow is recroded at a ±0.01 m/s, direction ±0.01° true north, and temperature ±0.001°C. Fish are identified to the species level. Sex and maturity are characterized using the standard survey macroscopic schemes. Fish ages are reported to the nearest year with the same protocols and precison as in the bottom trawl survey database.

Completeness Report:

Data collection and auditing are ongoing. The status of auditing should be checked before the use of any data.

Quality Control Procedures Employed:

Hand entered data is confirmed while on the vessel and secondarily in post cruise processing. Limited data auditing procedures are available while at sea. Standardized data auditing to identify erroneous entries or extreme values are conducted during post cruise processing and import of data. Morphometric data are checked against standard species specific regressions. Some unique data types still have auditing procedures under development (e.g. current data).

Data Management

Have Resources for Management of these Data Been Identified?: Yes
Approximate Percentage of Budget for these Data Devoted to Data Management: Unknown
Do these Data Comply with the Data Access Directive?: Yes
Is Access to the Data Limited Based on an Approved Waiver?: No
Approximate Delay Between Data Collection and Dissemination: A few weeks to 6-9 months dependent on the data type and end users need. For some of the unusual data types the tables are still being designed, therefore these data remain incompletely available.
Actual or Planned Long-Term Data Archive Location: To Be Determined
If To Be Determined, Unable to Archive, or No Archiving Intended, Explain:

Data will be archived once a solution for archiving relational data sets is defined

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?:

Archival of source data preserving unaltered collected data, Scheduled backups, Remote storage backups, Password protection


Lineage Statement:

The survey data began to be collected in the field in April 2014. A dedicated database began to be designed for storing the data starting in fall 2014.

Child Items

Rubric scores updated every 15m

Rubric Score Type Title

Catalog Details

Catalog Item ID: 27731
GUID: gov.noaa.nmfs.inport:27731
Metadata Record Created By: Patricia L Jones
Metadata Record Created: 2015-10-06 16:32+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2022-08-09 17:11+0000
Metadata Record Published: 2016-12-13
Owner Org: NEFSC
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2016-12-13
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2017-12-13