Why We Are Sampling During the Transit on the Southeast Shelf

Some have asked why we are sampling on our transit on the southeast US shelf.  Many species fished in the northeast may spawn or in some other way originate in the southeast.  For example, chub mackerel (Scomber colias) adults are fished in the northeast, but larvae have not been collected in our 40 years of sampling the shelf north of Cape Hatteras.  Also, historically southeastern species, such as blueline tilefish (Caulolatilus microps), are beginning to occur in the northeast so regularly that fisheries are emerging in the northeast. Like the Slope Sea, this region has had relatively little plankton sampling as compared to the northeast US shelf and Gulf of Mexico.

There has been sampling on the southeast shelf; with ichthyoplankton (eggs and larvae of fish) collections going back at least to 1965-1968 from the R/V Dolphin cruises.  There have also been a couple of monitoring and collaborative research programs. The Marine Resources Monitoring, Assessment and Prediction (MARMAP) program sampled portions of the southeast shelf in the 1970s and 1980s.  During the 1990s and early-2000s, sampling was conducted from South Carolina to southern Virginia as part of the South Atlantic Bight Recruitment Experiment (SABRE).  So, the absence of data points in the map below is due to infrequent sampling and also highlights the need to compile historic data to allow us to compare the past to the present.  A new collaborative effort between the Oceans and Climate Branch from the NEFSC and the SEAMAP Plankton group from the Southeast Fisheries Science Center is beginning to compile these data and attempt to fill in gaps and compare historical data with current conditions with cruises like this.

map of plankton collection locations.png

Map of ichthyoplankton collection locations on the east coast of the US and Gulf of Mexico with the location of bongo tows represented by red dots.  The map is a product of the Fish Larvae Explorer (FLEx) project, which is a collaborative product of the NOAA Fisheries And The Environment (FATE) and Coastal & Oceanic Plankton Ecology, Production & Observation Database (COPEPOD) projects.  FLEx was created to develop the use of ichthyoplankton time series as indicators of ecosystem status and to enhance ecosystem-based fishery management.

We are sampling some cross-shelf transects on our transit south to compare with historical collections.  Our first transect in Onslow Bay, North Carolina,  along a frequently sampled transect from the SABRE project will provide important data on how distributions and oceanographic conditions are changing over time.  We plan to collect as many plankton samples as possible before docking in Cape Canaveral on June 23.

Harvey Walsh
Chief Scientist
NOAA Ship Gordon Gunter  GU 1702




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