Apparently they are also tying large sunken ships to the cats and forcing them to pull them to the surface in various salvage operations.

Notice that the ship shown here is so large that you can barely see the single kitten they tied it to.
As much as I dislike having kitties for slaves, you can't go wrong with the guys who raised the fracking RMS Titanic! These are probably the only guys to bring 46,328 tons of steel and wood vertically 12,460 feet to the surface!