Dataset: NEFSC Survey Adult Fish Biomass
Deployment: NEFSC-Bottom_Trawl

Adult fish biomass of the Northeast U.S. Shelf Ecosystem: 1968-2012

Principal Investigator:

Dr Kristin Kleisner (Northeast Fisheries Science Center - Woods Hole, NOAA NEFSC)

BCO-DMO Data Manager:

Ms Dicky Allison (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Northeast Fisheries Science Center Bottom Trawl Survey (NEFSCBottomTrawl)

Current State:

Final with updates expected

Version:

first

Version Date:

2016-02-03

Data URL:

https://www.bco-dmo.org/dataset-deployment/637780/data

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Description

Biomass data of adult fish species of the Northeast U.S. Shelf; bottom trawl surveys were conducted by the Northeast Fisheries Science Center (NEFSC) between 1963-2013.

Methods & Sampling

Dataset acquisition description

The Northeast Fisheries Science Center (NEFSC) has conducted bottom trawl surveys for juvenile and adult fish on the Northeast US Shelf since 1963 (Azarovitz 1981). The surveys were conducted in the spring (March-April) and fall (September-October) using a stratified random design. All fish for each species were counted and weighed. These data represent kg of fish per tow. Zero means no fish of that species were caught in that tow.

Temperature and salinity values were obtained with a surface bucket for the temperature and a surface water sample was collected for a subsequent salinity measurement. In inshore areas, a bottom salinity was also taken.

References:
Azarovitz TR. 1981. A brief historical review of the Woods Hole Laboratory trawl survey time series. Canadian Special Publication of Fisheries and Aquatic Sciences. 58:62-7. (PDF)

Data Processing Description

Dataset Processing Description

Biomass of adult fish was calculated yearly between 1963 and 2012 for spring and fall. The number of strata in the bottom trawl survey is 108.

Unlike the 'stratum' of the adult fish numbers data, the 'strata group' of the biomass data represents a code. For example offshore strata 1 is coded as 01010 with the first 01 representing the strata group, the second 01 the strata number and the last 0 the substrata (Only a few have these where a strata was broken in half). R truncates the 01 strata group to 1 so in R the offshore strata 1 is 1010. Inshore strata start with 03 and offshore south of Hatteras start with 08, inshore south of Hatteras 07, and shellfish 06.

References:

Azarovitz TR. 1981. A brief historical review of the Woods Hole Laboratory trawl survey time series. Canadian Special Publication of Fisheries and Aquatic Sciences. 58:62-7. (PDF)

BCO-DMO Processing:
- Replaced spaces with underscores in taxa names.
- Modified parameter names to conform with BCO-DMO naming conventions.
- Replaced 'NA' in environmental measurements with 'nd'. Replaced 'NA' in fish biomass columns with '0'.

More information about this dataset deployment

Instruments

bucket

Supplied Name: bucket for salinity sample

Supplied Description:

buckets were used to collect water for salinity samples at the surface and if not too deep, the bottom.

Instrument Type

Generic Name: bucket

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0536/

Generic Description:

A bucket used to collect surface sea water samples.

bucket thermometer

Supplied Description:

thermometer encased in a small, thick plastic bucket with a rope attached.

Instrument Type

Generic Name: bucket thermometer

Generic Description:

a thermometer embedded in a small, sturdy, thick plastic container with a rope attached. Heave the bucket overboard and it catches water and the thermometer inside reads the temperature.

Otter Trawl

Supplied Name:

Supplied Description:

For specific details on the adult fish collection gear, see:
Azarovitz TR. 1981. A brief historical review of the Woods Hole Laboratory trawl survey time series. Canadian Special Publication of Fisheries and Aquatic Sciences. 58:62-7. (PDF)

Instrument Type

Generic Name: Otter Trawl

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/61/

Generic Description:

Otter trawls have large rectangular otter boards which are used to keep the mouth of the trawl net open. Otter boards are made of timber or steel and are positioned in such a way that the hydrodynamic forces, acting on them when the net is towed along the seabed, pushes them outwards and prevents the mouth of the net from closing. The speed that the trawl is towed at depends on the swimming speed of the species which is being targeted and the exact gear that is being used, but for most demersal species, a speed of around 4 knots (7 km/h) is appropriate. More: http://en.wikipedia.org/wiki/Bottom_trawling

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
common name biomass	Biomass of each species, described by common name.	kg per tow	wet_weight_biomass
year	4 digit GMT year	dimensionless	year
season	Spring or Fall	dimensionless	season
strata_group	4 digit code. first digit is region, second two digits are stratum and last digit is subsample of stratum. Zero in the last digit means the strata was not subsampled.	dimensionless	no_bcodmo_term
lat	Strata latitude center in decimal degrees	decimal degrees	lat
lon	Strata longitude center in decimal degrees	decimal degrees	lon
cruise_id	Cruise Identifier is six-digit number representing the four digit year of cruise deployment and the two digit sequential cruise within that year.	numbers	cruise_id
vessel_abbrev	Two digit abbreviation for ship. AL=Albatross IV, etc.	two digit abbreviation	ship
station	Sequential station number for each cruise_id.	number	station
depth	depth of the trawl	meters	depth
temp_surface	temperature at the surface	degrees Celsius	temp
sal_surface	salinity at the surface	dimensionless	sal
temp_bottom	temperature at the bottom	degrees Celsius	temp
sal_bottom	salinity at the bottom	dimensionless	sal
site	general location of the tow; GOM: Gulf of Maine; SS: Scotian Shelf; MAB: Mid-Atlantic Bight;GB: Georges Bank	text	site

Database

Contribute Data

Dataset: NEFSC Survey Adult Fish Biomass
Deployment: NEFSC-Bottom_Trawl

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: NEFSC Survey Adult Fish BiomassDeployment: NEFSC-Bottom_Trawl

Dataset acquisition description

Dataset Processing Description

Dataset: NEFSC Survey Adult Fish Biomass
Deployment: NEFSC-Bottom_Trawl