Entry in progress—B.P.

Wiktionary: lobster shift
Noun
lobster shift (plural lobster shifts)
1. a work shift that covers late evening and early morning hours.

Merriam-Webster Dictionary
lobster shift noun
Definition of lobster shift
: a work shift (as on a newspaper) that covers the late evening and early morning hours
— called also lobster trick
First Known Use of lobster shift
circa 1933, in the meaning defined above

Newspapers.com
27 December 1904, Paducah (KY) Evening Sun, pg. 4, col. 3:
THIRD PROMOTION IN THREE MONTHS
Mr. I. S. Cobb Night Editor Of New York Sun.
Has Charge of an Entire Crew Who Get Out the Early Edition of the Paper.
(...)
He (Irvin S. Cobb—ed.) now has charge of the force which prepares matter for the early edition of the Sun. This edition goes on the street at 10 a.m. and in New York newspaper parlance, the crew is known as “the Lobster trick.”

They go to work at 2 a. m. and quite work at 8 a. m. when the regular staff takes charge.

Newspapers.com
20 March 1905, Poughkeepsie (NY) Daily Eagle, pg. 4, col. 1:
“LOBSTER” NEWSPAPERS.—In New York, where such a multitude of various newspaper editions are gotten out, there is a class of men who work from about two o’clock in the morning until nine in the forenoon. When they come to work the proofs in the regular morning editions are placed before them and they go to work on them. They rewrite and elaborate and “fake” as much in addition as they dare, and then what they produce is put in type and printed in editions which are issued about nine o’clock in the morning, but which are called “evening papers,” being designed especially for the consumption of places at a little distance from New York, where there may be people foolish enough to believe that such a rehash of what has already appeared in the regular morning editions includes later news and therefore buy it. The men who do this work are known to the trade as the “lobster shift,” and the term, with all the significance that it has attained in the current slang of the day, ought to be applied to the stuff they prepare and the newspapers which print it.
(...)
The gullibility of some people seems to be without limit, but we should think that people of common sense would learn after a while to know that things printed in these “lobster” editions, which only have their origin in the “lobster” shift, are not worth reading, no matter how cheap these editions are sold, or how big head they have, or how loudly they are announced by their venders.

OCLC WorldCat record
On the “lobster shift”, or, the Herald’s star reporter
Author: A Howard De Witt; Dime Novel Collection.
Publisher: New York : Frank Tousey, 1906.
Series: Wide awake weekly, no. 20.
Edition/Format: Print book : Fiction : Juvenile audience : English

Newspapers.com
20 May 1906, Chicago (IL) Sunday Tribune, “Machines Weave Magic Spell Over Men Operating Them” by Clyde Haines, Worker’s Magazine, pt. 6, pg. 1, col. 6:
Complete Absorption of Operator.
(...)
In some of the big job offices they run a ‘lobster’ shift—from 1 till 7:30 in the morning.

Google Books
Making a Newspaper
By John La Porte Given
New York, NY: Henry Holt and Company
1907
Pg. 106:
In the office of an evening paper which issues a very early edition the man who reads the papers begins work at 2 o’clock in the morning, and half an hour later the four or five reporters constituting what among newspaper men is known as the “gas house gang,” because supposedly there are some gas house laborers who start to work at 2.30 o’clock in the morning, report for duty. Almost always these reporters, who usually refer to their period of work as the “lobster trick,” arrive sleepy-eyed and out of humor.

Newspapers.com
5 May 1907, The Illustrated Buffalo Express (Buffalo, NY), “Grist for Mark’s Advertising Mill,” pg. 15, col. 5:
The story created a sensation among the humorist’s (Mark Train’s—ed.) friends, but long before they were awake or knew anything about it, the home of Mr. Twain in lower Fifth avenue was surroudned by several battalions of evening newspaper reporters who work on the lobster trick and help to get out the lemon edition at 5 a. m.

Newspapers.com
14 February 1911, Atchison (KS) Daily Globe, pg. 4, col. 4:
“Jim" Howe, of Atchison, a Reporter on the New York Journal, Writes of His Experiences
(...)
One gang goes on at 2 o’clock in the morning ,and is through at 10 o’clock. This is called the “lobster” shift.

The “lobster” shift, owing to the undesirable hours, works only seven hours. The other shifts on the Hearst newspapers work eight hours.

Google Books
Stickfuls:
Compositions of a Newspaper Minion
By Irvin Shrewsbury Cobb
New York, NY: George H. Doran COmpany
1923
Pg. 146:
In Park Row parlance the staff that gets out this 8 A. M. edition is known as the lobster trick. A man assigned to that shift says he is working on the lobster.

Newspapers.com
26 March 1943, Honolulu (HI) Advertiser, “Miss Fixit Answers,” pg. 8, col. 5:
In journalism, “lobster shift” or “lobster trick,” means the duty after the morning paper has gone to press and before the arrival of the day staff—called also “sunrise watch.”

American Heritage
The Lobster Shift
February/March 1993
Volume 44 Issue 1
As a graduate of one newspaper’s postmidnight “lobster shift,” I recall being told in the late 1940s one theory regarding the origin of that expression, mentioned in the July/August edition (“Brisk Walk and Brusque Talk” by Gene Smith). And it doesn’t involve the beloved lobster, in any condition. The root of the word is merely “lob,” an English slang import meaning blockhead, buffler, idler, or similar pejorative applied to journalistic neophytes who were routinely assigned to this dead period, generally to keep them out of the mainstream of news—and thus out of trouble’s way.

Google Books
I, Lobster:
A Crustacean Odyssey
By Nancy Frazier
Durham, NH: University of New Hampshire Press
2012
Pg. 37:
The New York press covered the rich and famous of the lobster palaces and coined a related phrase of its own, “lobster trick.” In the 1940s, the newspaperman H. L. Mencken was asked for help in drawing up a definition of the term, which by then was outdated. He described it as a work shift that started after midnight: “In those days anyone who was astir at 2 a.m. was regarded as a gay dog, and gay dogs were currently supposed to spend all their time after midnight eating lobster and drinking champagne with chorus girls. It is thus quite possible...that the lobster trick at the start meant a tour of duty during the lobster hours.”

Google Books
Cassell’s Dictionary of Slang
By Jonathon Green
New York, NY: Sterling Publishing Company, Inc.
2005
Pg. 890:
lobster-shift n. (also lobster-trick) [1920s+] (US) a late-night work shift, [the slow pace of the crustacean, i.e. such a shift, usu. between 2 a.m. and 9 a.m. is rarely busy]

Google Books
The New Partridge Dictionary of Slang and Unconventional English
Edited by Tom Dalzell and Terry Victor
New York, NY: Routledge
2013
Pg. 1407:
lobster shift noun a work shift starting at midnight US, 1942

Gothamist
The End Of The ‘Lobster Trick’ And The Slow Death Of Overnight NYC Tabloid Journalism
BY JB NICHOLAS
OCT. 17, 2019 12:31 P.M.
(...)
Two weeks ago, the Daily News eliminated its overnight shift for news photographers, known as the “lobster trick.”
(...)
“They called it the lobster trick,” (Charles—ed.) Ruppmann said. “They called it that because that’s when the lobster came in, when they brought it into the Fulton Fish Market.”

Ruppmann explained, “In the lobster trick there were two shifts. You could be assigned from 12 to 8 a.m., or you could be assigned from 1 to 9 a.m.”