how can the sea off Gaza be Israeli territorial waters?
Because Gaza is not a state under international law, neither is Palestine.
I guess you are asking a rhetoric question because of your generally well-infomed posts elsewhere, but in case you were being ironic, and to inform the ignorant, Palestine has applied for statehood and the vote is due in the UNSC later this month. The UNSC will certainly vote to give Palestine full statehood, but the USA will issue its unilateral veto.
Worldwide condemnation will follow (probably closely timed with a Turkish confrontation with Israel).
The credibilty of the US unilateral veto on the UNSC will thus be further weakened, NATO will be weakened (even though France and UK will vote for Palestinian statehood), and the hand of China, Russia and Al Quaida (in the sense of a loose Muslim disaffection with world affairs) will be further strengthened.
However the US will continue to pay US$billions in foreign aid to Israel, so we'll continue to dig our own grave...