Northeast Fisheries Science Center
Oceanography Branch

Monthly Ecosytem Indices

Cooperating merchant ships are used by the NMFS Northeast Fisheries Science Center to provide approximately monthly monitoring of plankton and oceanographic conditions along standard transects across the Gulf of Maine (Massachusetts to Cape Sable, Nova Scotia) and Middle Atlantic Bight (New York to the Gulf Stream). Observations along the cruise routes, from most recent data collected and processed, are shown in comparison with historic-mean conditions for the same time of year. Data collected and shown are surface and bottom temperatures from expendable bathythermograph drops (XBT's), surface salinity from bucket samples, and total copepoda and phytoplankton biomass from analysis of Continuous Plankton Recorder (CPR) tow samples, collected at a depth of 10 meters.

Background On Monthly Ecosystem Indices

Merchant ships are used as part of an NMFS Northeast Fisheries Science Center (NEFSC) effort to monitor changes and status of the U.S. Northeast Shelf Ecosystem in relation to possible effects on the long-term sustainability and recovery of fisheries in the northeast. In 1961, the British began monthly monitoring of 10m depth plankton using the Hardy Continuous Plankton Recorder (CPR) aboard merchant and other ships on an opportunistic basis in the western North Atlantic. Beginning in the late 1960's, NMFS established several interagency and international agreements that either started complementary monitoring or supported continuation of existing ocean monitoring. Expendable bathythermograph and bucket surface temperature and salinity sampling were added to the CPR sampling in 1977 under what is now known as the Ships of Opportunity (SOOP) program in the NEFSC.

Since 1978, CPR, water column temperature and surface salinity have been routinely collected, approximately monthly, along two standard transects across the Gulf of Maine and the Middle Atlantic Bight. Sampling in the Gulf of Maine is between Boston, Massachusetts, and Cape Sable, Nova Scotia, currently using the C/V Skogafoss, Skogaline Ltd. St. John, Antigua, and Middle Atlantic Bight sampling is from New York to the Gulf Stream along the cruise route of the C/V Oleander, Bermuda Container Lines, as it transits between New York and Bermuda. Data collection and processing procedures for water temperature and salinity data are described in Benway et al. (1993), and for plankton collected in Jossi and Smith (1990). Methods used for developing historic means and variability, and for comparisons with current, monthly collections shown in the Monthly Ecosystems Indices figures, are presented in Benway et al. (1993).

References cited:

Benway, R.L., J.W. Jossi, K.P. Thomas and J.R. Goulet. 1993. Variability of temperature and salinity in the Middle Atlantic Bight and Gulf of Maine. NOAA Tech. Rep. NMFS 112, U.S. Dept. Commerce, 108 p.

Jossi, J.W. and D.E. Smith. 1990. Continuous plankton records: Massachusetts to Cape Sable, N.S., and New York to the Gulf Stream, 1989. NAFO SCR Doc. 90/66, Ser. No. N1788, Northwest Atl. Fish. Organ., 11 p.

This information provided by Jack Jossi, NMFS, Narragansett.

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