Bottom grading apparatuses for aquaculture systems

1. A system comprising:

a vessel filled with water that receives fish, the vessel having a bottom surface with drain;

a plenum in fluid communication with the vessel, the plenum comprising a plenum housing having at least two outlet interfaces that comprise a mortality conduit and a harvesting conduit;

a multiway valve in fluid communication with the plenum, a mortality pipe, and a grading pipe;

a mortality container in fluid communication with the mortality pipe and the vessel, wherein the mortality container is positioned near an upper end of the vessel; and

a shunt fluidly connecting the mortality container to the vessel, wherein the fish can re-enter the vessel from the mortality container through the shunt, and deceased fish remain in the mortality container, and

wherein when the multiway valve is closed to the mortality pipe, the fish will divert through the grading pipe.

2. The system according to claim 1 , wherein the bottom surface of the vessel is sloped towards a central axis of the vessel.

3. The system according to claim 1 , wherein the mortality container comprises a filter section output conduit.

4. The system according to claim 3 , wherein the shunt extends into the vessel, the shunt allowing live fish traveling through the mortality pipe to re-enter the vessel.

5. The system according to claim 1 , wherein the multiway valve comprises a first outlet that couples with the grading pipe and a second outlet that couples the mortality pipe.