The last major update to Minecraft dimension of the oceans dropped, now you can populate with this mod.
Oceancraft 1.7.2 and 1.7.10 is focused on improving ocean biomes biomes beach, adding up to 10 new mobs, including sharks, seagulls, crabs, stripes, different kinds of fish, sea turtles, whales and human cannibals find on the beaches of Minecraft.

Detail and Download here : Oceancraft Mod

Homepage: Mods for Minecraft