Results from first observational program of bioluminescence (BL) potential in the Delaware Bay area are presented. During the field program July 30–August 1, 2015, the satellite Visible Infrared Imaging Radiometer Suite (VIIRS) imagery shows the development of the submesoscale filament with elevated chlorophyll-a in the area of interaction of lighter water masses of the Bay outflow with denser upwelled water. We have shown that ageostrophic secondary circulation (ASC) cells contributed to the development of this filament. Analysis of BL potential observations have shown elevated values of BL potential in the area of the submesoscale filament. Analysis of observed temperature, salinity, sigma-t, and BL potential along the stations crossing the Bay mouth have shown a presence of a strong frontal structure separating colder, more saline, denser offshore water from the bay water masses. Over 3 days of sampling, this frontal structure moved onshore to the entrance of the bay, and brought offshore BL plankton communities with higher values of BL potential. We compared two surveys (at the end of July and in the middle of August) of water masses located in the area where the buoyant outflow of the Delaware Coastal Current is turned around and taken to the north up the shelf by upwelling favorable winds. Analysis of observations shows that the survey at the end of July has fresher water masses (due to higher river runoff before and during survey) and higher values of BL potential in comparison to the survey at the middle of August.