Green’s Dictionary of Slang

Block Island turkey n.

(US) salt cod.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1910		(con. mid-19C) W.B. Weedon Early Rhode Island 294: The family apparel was carried in a band-box, ‘a Block Island trunk,’ and when they reached home they feasted on a ‘Block Island turkey,’ i. e., Codfish.
1912		Norwich Bull. (CT) 12 Nov. 2/4: [headline] Bohemians After Block Island Turkey. A number of the members of the Bohemian club [...] will take two or three powerboats [...] for a codfishing trip.
1922		Nowwich Bull. (CT) 2 Dec. 6/4: Members of the Fisherman’s Club did not elect to eat what [...] is called Block Island turkey.
1938		J. E. Rattray Montauk (2001) 86: In the fall, there is striped bass, stuffed with tomato, onion and crumbs, and baked; in winter, codfish is often cooked the same way (this is called Block Island turkey).