On the right of salvage.

I'm going to speak generally as it is slightly different from country to country. Crab pots aren't a problem because 1- they are rarely adrift and adrift is always a requirement 2-They aren't worth very much and you can't just outright steal the things.

They were conceived under the idea that if you risk your boat and/or your life saving someone else's very likely valuable property, they shouldn't just be able to go "thanks" and walk away. I think this is probably good in principle, and in the vast majority of cases there are no problems and mariners do right by one another.

They vary from country to country though, and sometimes the locals want to take advantage of foreigners anchored in their waters because they know the courts will side with them and they know the details of local law.

Anyway, to the crab pots, you can only claim salvage fees and put a lien, you don't just get to keep the property. The salvage fees are usually statutorily defined as a percentage of the property value. 10% is a pretty common amount depending on the country.

If you (or a local) go round up a bunch of crab pots you've probably just pissed off a bunch of locals at $10 a crab pot. A judge is going to laugh at you, a bunch of locals are going to show you the anchors they use on their pots, and you'll be lucky if you're just ordered to give them back.