Fall Bottom Trawl Survey

The standardized NEFSC Fall Bottom Trawl Survey was initiated in 1963 and covered an area from Hudson Canyon, NY to Nova Scotia, Canada. Throughout the years, coverage has extended as far south as Florida and sampling depths have ranged from <27 to 366 m. Currently, the survey coverage is from Cape Hatteras, NC to Nova Scotia and the minimum depth range is > 18 m as the result of a change in the sampling platform. This has resulted in the exclusion of many inshore strata.

The purpose of the Fall Bottom Trawl Survey is to determine the seasonal distribution, relative abundance, and biodiversity of fish and invertebrate species found on the continental shelf during the fall months, typically September to November. Other cruise objectives are: to collect biological samples for age determinations and growth sutidies, fecundity, maturity, and feeding ecology; opportunistically test trawl gear, methods, or survey-related equipment that may benefit the trawl survey in the future; collect oceanographic data, inclduing CTD casts as well as samples of ichthyoplankton and zooplankton for relative abundance and distribution studies; and to collect hydroacoustic data between stations. Fishery scientists use the data to assess 45 stocks of commercial and recreational fish and invertebrate species in the northeastern United States.

The time series for the Fall Bottom Trawl Survey began in 1963 with data collection and quality assurance occurring with both paper and digital methods throughout the time series. Data consumers occasionally find questionable data from earlier paper collected data that requires verification via the original paper log. The frequency for such verification is minimal.

The provided Fall Bottom Trawl Survey time series from 1963 - most recently audited data set contain standard audited raw survey results without adjustments for changes in gear and/or vessel over the length of the time series. All "good" tows are included in these data sets. Additional non-representative tows are available upon request only. All inquiries for obtaining calibration information for vessel and gear changes should be addressed to the Chief of the Population Dynamics Branch or Chief of the Resource Evaluation and Assessment Division of the Northeast Fisheries Science Center (NEFSC).

The provided data sets contain the following information:

Station Data - Vessel-related information (e.g., cruise ID, location, speed, course, etc.) and surface and bottom sea water temperature and salinity

Aggregate Species Data - Tow-by-tow total weight and number of each species.

Species Length Frequencies - Summarized number of fish measured at each length interval

Individual Fish Data - Additional parameters collected from individual fish (other than length): sex, individual weight, gonad stage, age, and overall volume of stomach contents.

Available to qualified researchers.

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 is 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.

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.

User must read and fully comprehend the metadata prior to use. Applications or inferences derived from the data should be carefully considered for accuracy. Acknowledgement of NOAA/NMFS/NEFSC, as the source from which these data were obtained in any publications and/or other representations of these, data is suggested.

RDBMS: Oracle

representative

High degree of accuracy. When there is species identification doubt at sea, the specimen is retained for taxonomy at the NEFSC or other taxonomic laboratory.

SCS and FSCS data collection software programs employ real-time validation and must meet database integrity constraints. Data are then subject to post-audits.

Archiving solution for Oracle Data Sets is yet to be determined.

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

Vessel sensor data are collected electronically using SCS. Catch and biological data are collected electronically using FSCS 2.0. At the completion of each cruise leg, a database copy is inserted into the shoreside database.