Soon afterward, Palestinian militants fired a rocket into southern Israel from Gaza that was intercepted by Israel's Iron Dome aerial defense system, the Israeli military said.
No Palestinian group claimed responsibility for the early Thursday rocket fire, which apparently was a response to the sealing off the fishing zone.
COGAT, the Israeli Defense Ministry body controlling the crossings with the coastal enclave, announced that Israel is barring Gazans from using the coastal waters until further notice "due to the continuous launching of incendiary balloons and kites from the Gaza Strip towards Israel."
Israel often restricts the offshore fishing zone in response to cross-border violence.
Israel and Egypt have maintained a blockade of the Gaza Strip since the Islamist militant group Hamas took power in 2007.
Hamas wants Israel to ease its blockade. For more than a year, it has led mass protests nearly on a weekly basis along Gaza's fence with Israel, highlighting the dire living conditions in the territory of 2 million people.
However, a cease-fire struck by Israel and Hamas in May to end the worst round of fighting since 2014 has largely held.
Israel says an easing of the blockade cannot be secured as long as violence continues along the frontier, including the protests and the launching of incendiary devices.