Well, you is not a letter. "U" is though. and the sea Urchin starts with 'U'.
Unicorn fish
Dolphin
Seals, sea lions, seahorses.
Manatee, Manta- Ray (sp?), Mackrel.
There are no ocean names starting with "R" - there is a sea, the 'Red Sea'.
uh a shark???????????
anemones
Sea guLL
No animals 'live' in Antarctica. Some sea animals, including sea birds, come to Antarctica's beaches to breed.
Names of baby sea animals?
Urchin
· Quillfish
Dolphins