Yes, you can use anything for bait.
Seatboch
Yes, the idea is to go out on a boat where the sea is deeper. That is why they call it "deep sea fishing." The ocean is usually more shallow closer to the shore and if you fish from the beach it is usually called surf casting or surf fishing or beach fishing.
the boat on breakwater beach to get a fishing pole
The fishing rod is hidden in Breakwater Beach. You need to have the ghost ray power so get that if you don't have it already. If you have it then go to breakwater beach and then walk all the way down as far as you can go into the water. You should see an old sunken boat. Use ghost ray on the boat and then you will see the fishing pole. Click on the fishing pole to get it.
sausages
Humans use fishing poles for fishing
You need to win it from fishing at Breakwater Beach. You need to get the fishing pole there first. If you have the Ghost Ray Power, use it on the broken boat in the water. Walk down from the entrance into the water as far as you can until you see the broken boat and then use ghost ray on it to get the pole. Then just keep fishing for a while and eventually you will win the diving helmet.
Sausages are usually used for spaghetti, not hot dogs. Specifically, Italian sausages. You would use about 20 Italian sausages. About 2 kilograms.
Yes some people use them for fishing
Commercial fishing uses drag nets and others use one "Long line" that has hooks. Recreational fishermen use fishing rod/reels, fly fishing, spear fishing and bow fishing.
edible animal left overs
Yes. Vienna is the capital of Austria and Austria is one of the countries that uses the euro.