Unless you really love salt, you want much less salinity in pasta than the sea (1-2% for pasta, 3.5% in the sea). Kenji Alt-Lopez says that you want your pasta water "as salty as you remember the sea is", not as salty as the sea actually is because it's way too much!
Maybe it is not exactly as salty as the sea :)
If you’ve ever been at sea and tried to use seawater to cook pasta, you’ll realize that it’s too much salt. 1:1 seawater to fresh water turns out perfect (and saves your fresh water).