I found the word dogfish in a dialog between two soldiers in A Farewell to Arms by Ernest Hemingway (page 195). Here is the relevant part of the dialog,
"Has the food really been short?"
"I myself have never had enough to eat but I am a big eater and I have not starved. The mess is average. The regiments in the line get pretty good food but those in support don't get so much. Something is wrong somewhere. There should be plenty of food."
"The dogfish are selling it somewhere else."
"Yes, they give the battalions in the front line as much as they can but the ones in back are very short. They have eaten all the Austrians' potatoes and chestnuts from the woods. They ought to feed them better. We are big eaters. I am sure there is plenty of food. It is very bad for the soldiers to be short of food. Have you ever noticed the difference it makes in the way you think?"
The dialog makes me think of this dogfish as people, not fish as defined in all dictionaries I tried. Perhaps it refers to people who speculated the price of food during the war, but I'm not sure.
What does this dogfish mean?