The pictured Arc was built at Mt. Arafat by Greenpeace, but people are building them for real, such as the Kwok brothers in Hong Kong. Theirs will have 67 pairs of fiberglass animals. It will remain on land for ease of animal care, unlike the Dutch version that actually floats and has real animals but is 1/5 scale, and which will sail to London, the US and Australia.
There are a million square miles of ocean so I don't think all the arcs and pirate patrols that could be built could ever guarantee safe passage.
In 1991, Somali fisherman levied "taxes" on foreign vessels that were overfishing their waters, calling themselves the Volunteer Coast Guard. Somalia's government had descended into anarchy. Foreign ships were also dumping nuclear waste in the area, and lead, cadmium and mercury, which caused radiation sickness when they washed up on shore.
This is all part of "a world beyond law and regulation," as it says in the article. Icelandic fishermen turned to bad banking investments; Somali fishermen turned to piracy - both bad business models. Who are the real pirates?