From the regs.
Summer Flounder (Fluke)
The possession and minimum size limit for summer flounder is five fish at
17.5 inches with an open season from May 5–Sept. 28.
Anglers may fillet one legal-sized summer flounder from their daily possession
limit catch for use as bait. This carcass, commonly known as the rack,
shall be kept intact so it can be measured for compliance with the minimum
size limit. No parts of any summer flounder caught on a previous fishing
trip shall be in possession; only fish just caught on this outing.
Page 14 here--good to have this anyway
http://www.state.nj.us/dep/fgw/pdf/2012/digmar12.pdf