We can't give a really solid mathematical answer because we don't know the density of the lobster. We also don't know if it's live lobster, boiled lobster, shelled lobster meat, etc..
Also this is assuming you have 3 coolers with a combined total of 552 cubic feet, not 3 coolers with 552 cubic feet each.
However, for a bit of rough figuring. . .
1 cubic foot = 29.9221 quarts
According to this site ( http://www.newenglandprovisions.com/mainelobsterrecipes/boiledmainelobster.html ) a standard 20 quart pot will hold about 10 pounds of lobsters.
552 cubic feet = 552 * 29.9221 = about 16517 quarts
16517 quarts / 20 = about 825.8 standard 20 quart pots
825.8 * 10 pounds = 8258 pounds.
So that (8258 pounds) is an answer, but it's really not the answer.
We don't know if you have just a pile of lobster or a bunch of 20 quart pots or what, so this answer is really just some quick and dirty figuring.