i'm not 100% shure that seals have back fins but until i'm 100% shure i'm going with yes
some kinds of seals
Porpoises have triangular dorsal fins (as opposed to the curved dorsal fins of dolphins and whales). Some species of porpoise have small bumps on their fins, but the purpose of these bumps is unknown.
Fish move by swimming. They move their fins back and forth to swim. Some fishes have a swim bladder which is an organ that help bony fish stay in different depth.
The fins act as stabilizer's. When the snake would make "S" movements in the water it was hard for it not to flip over at some point. So, it has developed fins on its back to works as a stabilizers which help to keep it right-side-up.
Shark is caught, then the fins are removed. With some sharks, the shark is thrown back to the sea after the fins are harvested, while with other sharks, liver/useful organs and flesh are removed for commercial sales.
Shark finning is the practice of catching sharks, cutting off (and keeping) the fins, and throwing the rest of the shark back into the ocean. Shark fins are regarded as a delicacy in some cultures.
Yes, sharks have paired fins, including pectoral fins (located on their sides) and pelvic fins (located on their underside). These fins help sharks with stability, steering, and maneuvering in the water.
Yes, all fish do have fins to help them swim. But some have very small fins, and some marine animals such as snakes and eels may not have true fins. Most fish have prominent fins at the end of their tails to guide them, as well as dorsal fins on their backs.
when people capture sharks they cut off their fins and then release them back into the water for dead because sharks can't swim without fins so they sink to the bottom of the ocean to drown because they have to come up for some air sometime but can't without fins
Provided the fish is given proper food and good conditions, yes the fins will grow back. The new fin(s) are never as perfect as the old ones. There is usually some deformity (scarring) resulting from the damage.
back and forth side to sife
no some have wings