Menhaden are bait species and there is no limit right now. There is some talk of putting a creel limit in, but nothing has been set yet.

Other than that, here's the applicable regulation information:

26-142a-6.Commercial fishing gear specifications
Commercial fishing gear shall conform to the following specifications:
(c) Gill nets
(1) In the inland district, gill nets shall have a mesh of not less than five inches when stretched except that nets used for taking white perch, catfish species and yellow perch shall have a mesh of not less than three and one half inches when stretched.
(2) In the marine district gill nets shall have a mesh of not less than three inches when stretched with the following exceptions:
(A) gill nets used for taking American shad shall have a mesh of not less than five inches when stretched;
(B) gill nets used for taking tomcod shall have a mesh of not less than one and one-quarter inches when stretched; and
(C) gill nets used for taking white perch, catfish species and yellow perch shall have a mesh of not less than three and one-half inches when stretched.
(3) The use of gill nets constructed of a single strand or multiple strands of material known as monofilament is prohibited for the taking of American shad from sunrise to sunset. The twine thickness of any such gill net shall be no greater than .28mm diameter.
(4) All gill nets being fished under authority of a personal use gill net license issued under section 26-142a of the Connecticut General Statutes shall be personally attended by the licensee.

26-142a-3a. Area-gear restrictions
(a) No commercial fishing gear shall be used for taking any fish in that portion of North Cove, as indicated by posters and known as Fall River, in the township of Essex.
(b) Pound nets and trap nets shall not be used to take any fish in the area lying between lines drawn south in Long Island Sound to the New York state line from Fenwick Dock, Old Saybrook, and from Mill Creek (Mile Creek), Old Lyme.
(c) No pound net shall be set less than five thousand two hundred and eighty (5280) feet from the documented location of any other pound net.
(d) No fixed commercial fishing gear shall be set at any time within any navigable channel as indicated by United States Coast Guard channel markers or within any fairway as designated by an approved harbor management plan adopted under Chapter 444a of the General Statutes. No fixed fishing gear shall be set in any mooring area as designated by an approved harbor management plan adopted under Chapter 444a of the General Statutes during the period May 1 through October 15. For the purposes of this section, fairway is defined as a harbor channel which is not marked by United States Coast Guard channel markers but is designated as a navigation channel in an approved harbor management plan; mooring area is defined as an area in which vessels are commonly moored with permanent mooring tackle, and fixed commercial fishing gear means the following: gill nets anchored or tied in a fixed position; trap nets; fyke nets; pound nets; and the buoys of fish pots, eel pots, or lobster pots including those set by holders of the personal use lobster license.