deep sea, n. — Green’s Dictionary of Slang

deep sea n.

1. stew (fish need not be a component; the image is of ingredients that ‘swim’).

1940

(con. 1914) S.J. Simonsen Soldier Bill 11: Bill learned at his first meal that [...] ‘deep sea’ meant stew.

deep sea chef

(US) a dishwasher.

1929		V.W. Saul ‘Vocab. of Bums’ in AS IV:5 339: Deep sea chef—A dishwasher.
1960, 1975		Wentworth & Flexner DAS.

deep sea fisherman (also deep sea gambler)

a confidence trickster working the transatlantic liners.

1913		Sun (NY) 27 July 40/1: Things are pretty tough. Nearly all the deep sea bunch are in London [...] every gun mowl [sic] America ever boasted of was over there where the getting’s good.
1940		D. Maurer Big Con 295: deep-sea gambler. See boat-rider.
1970		R. Fabian Anatomy of Crime 193: Deep-Sea Fisherman: Card-sharper on a liner.

deep see shark (n.) [rhy. sl. = nark n.¹ (1)]

(N.Z. prison) an informer.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 54/2: deep sea shark n. an informer.

deep sea turkey (US)

(also submarine turkey) salmon.

1918		L. McCoy letter 29 Sept. at BrownCountyGeneaology.com 🌐 Also, what also is known in the states as corned beef but here it’s ‘corned willie’ or ‘old charley’; also salmon is ‘deep sea turkey.’.
1921		DN V 111: Deep-sea turkey, n. Salmon.
1940		Waukesha (WI) Freeman 24 Jan. 3?/3: ‘Submarine turkey’ – salmon steak.
1944		P. Kendall Dict. Service Sl. n.p.: deep-sea turkey . . . salmon.
1963		Outlook (Waverly, NY) (Nov.) II:12: We will be particularly mindful of you all, therefore, [...] when we sit down to our Thanksgiving dinner of ‘deep-sea turkey’.
2002		(ref. to 1917) Brief Hist. of Company C (87th Division, 346th Infantry) 🌐 There being no ham on hand, Great Gobs of Goldfish or Deep Sea Turkey were immediately dispatched with a quantity of beans as a change from the regular army food.