Seafood

“Sea food” is a common term today, but it wasn’t used in the 1700s. “Sea food,” if used at that time, had the meaning of the food that sailors ate aboard ship, such as salt pork and crackers. Edible fish and shellfish come under the modern definition of “seafood.”
 
Early citations for “sea food” (at first written as two words) appear in the 1820s, almost exclusively from Connecticut. It is not known who, if anyone, coined the term.
 
The hyphenated form—“sea-food”—existed from that 1820s beginning. “Seafood” (written as one word) became common by about 1900.
 
 
Wikipedia: Seafood
Seafood is any sea animal or seaweed that is served as food, or is suitable for eating by humans, such as fish and shellfish (including mollusks and crustaceans).
 
Edible seaweeds are also seafood, and are widely eaten around the world. See the category of sea vegetables.
 
The harvesting of seafood is known as fishing and the cultivation of seafood is known as aquaculture, mariculture, or in the case of fish, fish farming.
 
Seafood is an important source of protein in many diets around the world, especially in coastal areas.
 
Merriam-Webster Dictionary
Main Entry: sea·food
Pronunciation: \-ˌfüd\
Function: noun
Date: 1836
: edible marine fish and shellfish
 
(Oxford English Dictionary)
seafood
orig. and chiefly U.S.
Food obtained from the sea; fish, crustacea, etc., used as food. Freq. attrib.
1836 Knickerbocker VIII. 423 She said that she had come to Screamy Point to get ‘sea-food’.
1906 N.Y. Even. Post 10 Mar. 5 Up State residents are among the best customers of the sea food, fruit and produce dealers.
1927 Weekly Dispatch 1 May 1/2 The correct name of the Poydras levee [at New Orleans] is the Carnavon levee, so named by the Carnavon family in England, who built it in 1870 to protect the plantation and seafood packing plant they then owned.
1935 A. BAUGH Hist. Eng. Lang. xi. 462 A writer in the London Daily Mail recently complained that an Englishman would find ‘positively incomprehensible’ the American words..sea-food,..and hired-girl.
1944 T. BARBOUR That Vanishing Eden 166, I was dining with some friends at a popular seafood restaurant in Miami.
1953 J. HILTON Time & Time Again I. 6 ‘I hope you like sea-food.’.. ‘Sea-food?.. Fish, that is? Oh yes, I do, indeed.’ (..True enough, though this ‘sea-food’ set Charles thinking that he also enjoyed ‘land~food’.)
1965 H. GOLD Man who was not with It III. xxv. 234 Grack’s contact man cooked in a diner on the seafood coast of Baltimore.
1978 K. HUDSON Jargon of Professions iii. 82 Twenty or thirty years ago..fish was upgraded to seafood.
 
6 March 1821, Connecticut Courant (Hartford, CT), pg. 4 ad:
The situation is remarkably pleasant, within less than 20 rods of the water, where all kinds of sea food of the best quality can be furnished on the shortest notice.
 
23 July 1921, Connecticut Mirror, pg. 3 ad:
He will keep constantly on hand a supply of the various kinds of sea food, and to those who are acquainted with the quality of the fish, lobsters, clams and oysters, taken at Killingworth, no further remark is necessary; but to those who are not, he begs leave to say, that they can be found in no greater perfection in any part of the state.
 
6 May 1822, American Mercury (CT), pg. 3 ad:
Notice
To all who are fond of sea food and bathing.
THAT pleasant stand situated on the Bans of Killingworth harbour is now kept by Ebenezer Hopson, who last season kept the house at Point Rocks in Guilford.
 
15 June 1825, Middlesex (CT) Gazette, pg. 3 ad:
No place on the Sound is better situated for persons labouring under any indisposition to enjoy the benefit of salt-water bathing, or of sea-food of all kinds—and no attention shall be wanting, on the part of the proprietor, to render his house a pleasant resort.
(...)
Sachem’s-Head, Guilford, Conn. June 15.
   
Google Books
The Monikins
By James Fenimore Cooper
Volume I
London: Richard Bentley
1835
Pg. 201:
He pined for a little pork—he cared not who knew it; it might not be very sentimental, he knew, but it was capital sea-food; his natur’ was pretty much pork; he believed most men had, in some way or other, more or less pork in their human natur’s; nuts might do for monikin natur’, but human natur’ loved meat; if monikins did not like it, monikins need not eat it; there would be so much the more for those that did like it—he pined for his natural aliment, and as for living nine years in an eclipse, it was quite out of the question.
(This “sea-food”—pork!—is the food that sailors ate on ships. This meaning is earlier than the popular one used today—ed.)
   
25 May 1839, Connecticut Courant (Hartford, CT), pg. 3 ad:
SEA FOOD!
A RARITY FOR HOT WEATHER!!
The subscriber offers for sale, at No. 1 Albany street, the following kinds of Salt Fish:
(Halibut, Cod, Haddock, Tongues and Zounds, Halibut’s Finds, Mackerel—ed.)
 
13 July 1902, New York (NY) Times, “Between the Dunes and the Deep Sea” by J. Herbet Welch, pg. SM13:
He gave Nora very careful instructions as to the preparation of his seafood, and before dinner insisted upon pouring us all out a cocktail, so that we might be able to do full justice to his contribution to the fest.