① The large yellow croaker breeding sea area requires good water quality and no pollution, the water depth is 7-15 meters, the water flows back and forth, the current is gentle, the flow speed does not exceed 1 meter/second, the transparency is 30-100 cm, and the salinity is 16 ‰-30‰, the best breeding water area is a sheltered bay surrounded by mountains. Correct;

② The fishing raft adopts the floating cage culture currently commonly used, that is, the fishing raft consists of a frame, a buoyancy device, a box and other accessories. The cage size is 3.1 meters × 3.1 meters × 3.5 meters (height), incorrect;

③ The size of the seedlings for stocking should be above 3.0cm (body length), correct;

④ Daily management is mainly to prevent escape and disease prevention , guard against enemies. correct.

It can be seen that D①③④ is correct.

So choose: D