Winter flounder. We worked on the little guys for a few years in Raritan Bay/Navesink. We conducted some growth studies of fish in cages in various habitats. There were a few days where we collected hundreds of the little guys from a small zone in one of Sandy Hooks coves. To find such numbers of fish the method and timing really has to be focused and precise.
I'm going to put in some extra effort this year to determine if the densities of the fish in those coves is the same. As soon at the water gets toasty in those coves the fish spread out and head into the bay and find deeper habitat.
The photo's are of Georges Bank fish.
http://www.asmfc.org/species/winter-flounder