What characteristics do Lake Van and Lake Tuz have in common?

I checked to see if more drownings did happen in lakes than the sea. I’m guessing that by "sea" you mean oceans. The Great Lakes are far larger than a number of "seas" around the world, and the Great Salt Lake is saltier than general ocean water.

My observations from local news stories in my part of the world, are that in Oregon, people are more likely to die by swept out to the Pacific Ocean by "sneaker waves" along the coast, even though there are warning signs posted at the state parks and beaches, than any other way of entering the water. More, though drown in lakes, reservoirs, and rivers because they aren’t wearing life vests, aren’t aware of the strength of currents, are surprised by the water temperatures, aren’t aware of underwater drop-offs, are drunk when they fall into the water from boats, over-estimate their swimming endurance/abilities, or are unsupervised children.

Basically, it seems that people don’t expect placid or smaller bodies of water like ponds and lakes to be as dangerous as the ocean and are thereby unprepared.