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Narragansett Lab: Ecosystem Monitoring Group

Oceanography Branch

  • Objectives
  • Shelf-wide Research Vessel Surveys
  • Ship of Opportunity Transect Surveys
  • Related Activities
Calanus finmarchicus

The objectives of the investigation are:

  1. to monitor the fishery-relevant components of the Northeast Shelf ecosystem, to characterize the baseline conditions and their variability, and to index the seasonal, annual, and decadal changes in the conditions of the ecosystem, and
  2. to determine the effects of biological and physical processes on the recruitment of Northeast shelf fishes, especially gadoids.

The Investigation utilizes three survey approaches to gather data on planktonic organisms and environmental parameters:

  1. shelf-wide Research Vessel Surveys;
  2. Ship of Opportunity (SOOP) Transect Surveys;
  3. sampling using a variety of environmental satellites and buoys (termed Remote Sensing Surveys).

Data generated by these surveys are analyzed by Center and outside scientists to determine zooplankton abundance, distribution and biomass estimates, time series of zooplankton abundances, and to establish baseline indices for zooplankton and hydrography in the northeastern US continental shelf ecosystem.

Bongo nets: devices used to collect plankton samples
carolyn griswold
Fisheries biologist Carolyn Griswold rinsing plankton sample from bongo net

Shelf-wide Research Vessel Surveys are conducted 6-7 times per year over the continental shelf from Cape Hatteras, North Carolina to Cape Sable, Nova Scotia, using NOAA research ships or charter vessels. Three surveys are performed jointly with the bottom trawl surveys in the winter, spring and autumn. An additional four cruises, conducted in winter, late spring, late summer and late autumn, are dedicated to plankton and hydrographic data collection. The Cape Hatteras to Cape Sable area is divided into four regions, and 30 randomly selected stations are targeted for sampling from each region (click to view area map and recent cruise reports). The following samples and data are collected routinely.

Zooplankton and Ichthyoplankton

Zooplankton and ichthyoplankton are collected throughout the water column (to a maximum depth of 200 meters) using paired 61-cm Bongo samplers equipped with 333 micron mesh nets. Samples are preserved in formalin for subsequent laboratory analysis. Over 300 plankton taxa are sorted, identified and enumerated by staff at the Sea Fisheries Institute in Poland through a joint studies program. Data received by the Ecosystems Monitoring Group is quality controlled and loaded into ORACLE tables at the Narragansett Laboratory.

For MARMAP Codes click here.

Water Column Temperature and Salinity

Water column temperature and salinity data are collected simultaneously with plankton tows using a Conductivity, Temperature and Depth (CTD) unit. Niskin bottles are used twice daily to collect water samples at depth for CTD salinity calibration. Near-surface temperature and salinity are measured every 15 seconds while the vessel is underway by means of a flow-through thermosalinograph. Data are logged directly to the shipboard computing system (SCS), with raw data maintained by Data Management Services (DMS), Woods Hole, MA, and with quality controlled data loaded into SAS data bases residing on the Narragansett Lab network. For selected analyses click here.

Surface in vivo Fluorescence

Surface in vivo fluorescence measurements are made while the vessel is underway via the flow-through system and recorded every 15 seconds on the SCS. Calibration samples are taken twice daily, with chlorophyl-a extracted and measured onboard. Raw data are maintained by DMS, and quality controlled data are loaded into SAS databases residing at the Narragansett Lab. For selected results, click here. Surface primary productivity measurements are made while the vessel is underway via the flow-through system. These fast repetitive rate fluorometer values have been successfully converted to carbon production rates, and design of quality controlled data bases is in progress.

Cruises last from 9 days to three weeks. Anyone interested in volunteering for a cruise should contact Jon Hare (PH: 401 782-3295; e-mail:

jack jossi
Oceanographer Jack Jossi retrieves CPR
CPR: Continuous Plankton Recorder

Ship of Opportunity (SOOP) Transect Surveys have been conducted monthly with the Hardy Continuous Plankton Recorder (CPR) across the Gulf of Maine since 1961, and from New York towards Bermuda since 1971. This unique towed body samples zooplankton and larger phytoplankton organisms at a depth of 10 meters. The resulting time series rank among the longest for the northwest Atlantic. Expendable bathythermographs (XBT's) and surface salinity measurements were added in 1977. Inter-institution agreements since the early 1990s have resulted in the acquisition and installation of an Acoustic Doppler Current Profiler (ADCP) and flow-through thermosalinograph. XBT and TSG operations on both the Gulf of Maine and Middle Atlantic Bights routes continue to be supported by the Atlantic Oceanographic and Meteorological Laboratory (AOML) in Miami, Florida. Their supports includes equipment, XBTs, software and computers in support of data collection on the two routes as part of a much larger global observation program AOML GOOS Center. AOML also provides logistical assistance for the SOOP program. (click here for more background information on the Ship of Opportunity Program).

Route MC extends from the Massachusetts/New Hampshire coast to Cape Sable, Nova Scotia, a distance of approximately 450 km, crossing Massachusetts Bay, Wilkinson Basin, the central Gulf of Maine ledges, Crowell Basin, and the western Scotian Shelf. Sampling along this route began in 1961.

Route MB extends from Ambrose Light off New York City toward Bermuda for a distance of approximately 450 km crossing the continental shelf, passing through shelf water, and usually extending in Gulf Stream water. Sampling along this route began in 1972.

Cruises on the MB route last one week and are aboard a merchant vessel. Anyone wishing to volunteer should contact Carolyn Griswold (401 782-3273,

Continuous Plankton Recorder (CPR) tows capture zooplankton and larger phytoplankton on 225 X 234 micron silk grit gauze at a standard depth of 10 m and at cruising speeds of 19-31 km/hr. The continuous record is cut into sections, each representing 18.5 km along the sampling track. Specimens on alternate sections are identified and enumerated by staff at the Narragansett Laboratory or at the Sea Fisheries Institute in Poland through a joint studies program. Data generated is quality controlled and entered into SAS datasets residing at the Narragansett Laboratory. For selected analyses, click here and here.

Water Column Temperature to a maximum depth of 750 m is measured at 19-63 km intervals via expendable bathythermograph (XBT). Near-surface temperature and salinity measurements are made and recorded digitally every 15 seconds while the vessels are underway utilizing a thermosalinograph. Water column temperatures are transmitted to shore sites via geostationary Operational Environmental Satellite (GOES) at one hour intervals. The XBT data are transmitted to the GOES receiving station on Wallops Island, VA and are stored at the National Weather Service. For selected analyses, click here.

Monthly Ecosystems Indices for the Gulf of Maine and the Middle Atlantic Bight are generated and posted on the internet. Data shown are surface and bottom temperatures from expendable bathythermograph drops (XBT's), and surface salinity from bucket samples or thermosalinograph (TSG) measurements. Indices of phytoplankton and zooplankton biomass are under development and will be posted on the webpage in the future.

Standard meteorological observations are made every 6 hours. Weather information is transmitted via Standard-C to COMSAT, a land based receiving station. Upon arrival, the data is passed to the U.S. Coast Guard for ship position updates and the National Weather Service for its model predictions.

The Voluntary Observing Ships (VOS) program provides all equipment (i.e., computer, XBTs, TSGs) and software to participating merchant ships through the Global Ocean Observing System (GOOS) program at AOML in Miami, FL (go to for a program description).

The Shipboard Environmental (data) Acquisition System (SEAS), supplied by VOS and developed by NOAA, provides accurate meteorological and oceanic data in real time from ships at sea through the use of satellite data transmissions. Data transmitted through either GOES or INMARSAT-C NOAA satellites are used in weather, climatological and ocean models. SEAS is installed on all NOAA and merchant vessels involved in the above described Ecosystem Monitoring activities.

On a monthly basis, the Narragansett Bay Project gathers data on the hydrographic and zooplankton conditions of the Narragansett Bay, RI via the NuShuttle, an undulating towed body that is outfitted with a CPR unit, optical plankton counter, dissolved oxygen sensor, fast repetitive rate fluorometer, CTD-fluorometer and a PAR sensor.

Click here for Ecosystem Monitoring Cruise Results

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