Frank E. Davis was a seafood concern in the commercial fishing town of Gloucester, which I have been many times. Gloucester had a business in town where McDonald’s Filet ‘o Fish were made. The Frank E. Davis’s 8 Central Wharf Rogers St headquarters may have demolished the over 50 years ago. Looking at a google map of the area now, you can see Gorton’s Fish, and Wholefoods Seafood facility.
Frank E. Davis company began shipping Mackerel in 1885. It mentioned in their 1930 booklet [reddit link] that they began with mackerel and later added variety such as codfish and lobster, canned. But before canning, it said in an 1894 flyer [eBay link no affiliation] Davis would ship you 200 lbs. of Mackerel for free to any part of the country. $20 in 1894 is worth $731.49 today — wholesale Mackerel today sells for about the same price.
In a biography of the owner, Frank E. Davis (1851- ) it said that he was in the “mail order business in salt and pickled fish and canned fish.” Before Davis began canning, in the late 1800s refrigerated railcars were available with an option to ship live fish in water, but it appears that Davis stayed with traditional salting and pickling.
Their mackerel and other fish would have been fished from Georges Bank. For an amazing account of the history of fishing and lobstering, I fully recommend “The Lobster Coast: Rebels, Rusticators and the Struggle For a Forgotten Frontier” by Colin Woodard.