New England: Eel (nickname)

Eel fishing was very popular in New England in the 19th century. “The Yankees are called Eels” was cited in an 1834 newspaper. “The Eels of New-England” was cited in a passage about American nicknames in an 1838 book.
 
The “eel” nickname was infrequently used in the 1800s and was historical by 1900.
 
 
19 August 1834, New York (NY) American, pg. 2, col. 2:
NAMES. A writer in the Illinois Pioneer says: that, the following nick-names have been adopted to distinguish the citizens of the following states:—
 
In Kentucky they’re call’d Corn-Crackers,
Ohio, ....................Buckeyes,
Indiana .................Hoosiers,
Illinois ..................Suckers,
Missouri, ...............Pukes,
Michigan, T. ..........Woolverines.
The Yankees are called Eels.
 
Google Books
The Clockmaker; or The Sayings and Doings of Samuel Slick, of Slickville
By Thomas Chandler Haliburton
London: RIchard Bentley
1838
Pg. 289:
These last have all nicknames. There’s the hoosiers of Indiana, the suckers of Illinoy, the pukes of Missuri, the buckeys of Ohio, the red horses of Kentucky, the mud- heads of Tenessee, the wolverines of Michigan, the eels of New England, and the corn-crackers of Virginia.
 
Google Books
8 September 1838, New-York (NY) Mirror (New York, NY), pg. 86, col. 2:
These last have all nicknames. There’s the Hoosiers of Indiana, the Suckers of Illinoy, the Pukes of Missouri, the Buckeyes of Ohio, the Red Horses of Kentucky, the Mud-heads of Tennessee, the Wolverines of Michigan, the Eels of New-England and the Corn-crackers of Virginia.
 
Google Books
Life in the New World,
Or, Sketches of American Society
By Charles Seatsfield
New York, NY: J. WInchester
1844
Pg. 55:
They would begin the struggle rather to-day than to-morrow; the Hooskiers from Indiana, the Suckers from Illinois, the Pukes from Missouri, the Red-horses from Kentucky, the Buckeyes from Ohio, the Wolverines from Michigan, the Eels from New England, the Mudheads from Gennessee, the Corncrackers from Virginia, they are all ready.
 
Google Books
Dictionary of Phrase and Fable
By Ebenezer Cobham Brewer
London: Cassell and Company, Limited
1895
Pg. 407:
Eel. A nickname for a New Englander.
 
Woods Hole (MA) Historical Museum
Eel Fishing
by Jennifer Stone Gaines
One fishery that has almost passed from our consciousness is eel fishing. It used to be a dependable standby. especially during the co ld and stormy weather when it was difficult and dangerous to fish offshore. The eels were caught close to home, in the salt marsh creeks, bays and estuaries. 1he importance of eels to the lives of the early setrlers can be gauged from Falmouth place names: not one but two Eel Ponds. and one Eel River.