Missions almost accomplished…

The Delaware II sailed Wednesday, November 30, on the DE 11-10 Ecosystem Processes Research Cruise.  The principal objective of the cruise is to locate and quantify concentrations of larval and juvenile fish.  The target species for this trip is Atlantic herring, which spawn on Georges Bank in the fall.  Sampling will be done primarily with a Bongo Net and a Video Plankton Recorder (VPR) towed simultaneously, and an Isaacs-Kidd midwater trawl (IKMT).  The bongo net collects zooplankton and larval fish, and the takes pictures of plankton as it is towed through the water.

VPr andf bongo nets hauled aboard

Crew member Chris Taylor hauls the Video Plankton Recorder (VPR) and Bongo Net aboard the Delaware II. (Photo by Chris Melrose, NEFSC/NOAA)

Sampling will be conducted in the western Gulf of Maine, southern New England waters, and adjacent to three drifters released on Georges Bank near larval Atlantic herring collections made during the November EcoMon cruise (DE 11-09).

midwater trawl comes aboard

Fisherman Jim Pontz hauls the Isaacs-Kidd midwater trawl aboard the Delaware II. (Photo by Harvey Walsh, NEFSC/NOAA)

In addition, we are trying to accommodate several other missions during our cruise.  We will conduct vertical casts with a Conductivity Temperature Depth (CTD) probe, a Laser In Situ Scattering Transmissometer (LISST), and Niskin water bottle.  The CTD relays real-time salinity (derived from conductivity), temperature, and depth back to the ship.  The depth is the most important; it allows us to monitor where our gear is during the tow.  We have CTDs on the wire during Bongo and IKMT tows, as well.  The LISST collects particle-size distribution profiles, which can be used to monitor how much plankton is in the water column.  The water bottle collects water samples for a Fluoroprobe designed to estimate the amount and types of phytoplankton in the water.

Three instruments retrirved

Fisherman Jim Pontz retrieves the Laser In Situ Scattering Transmissometer or LISST (black probe), the Conductivity Temperature Depth or CTD (white instrument), and a Niskin Bottle (gray bottle) from a vertical cast. (Photo by Harvey Walsh, NEFSC/NOAA)

Prior to sailing, we were asked to retrieve a Northeastern Regional Association of Coastal Ocean Observing Systems (NERACOOS) buoy that was drifting in the vicinity of Jordan Basin.  We also plan to conduct visual survey transects for sea birds in conjunction with an ACROBAT towed sensor body, which collects temperature, salinity, turbidity, chlorophyll, light, nitrate, and oxygen level data.  The transects are located adjacent to Nantucket Shoals, an area of high concentrations of sea ducks this time of year.  If the weather cooperates, we hope to accomplish all our missions.

Harvey Walsh
Chief Scientist
DE11-10 Ecosystem Processes Research Cruise

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