Canada and the U.S. should ban the export of water from the Great Lakes because the lakes don’t have a surplus, says a preliminary report released yesterday by the International Joint Commission, the U.S.-Canada agency that regulates the lakes. Canada yesterday threw its support behind a commission recommendation for a six-month moratorium on the large-scale removal and sale of water from the lakes until the agency releases its final report next February. Canada, which is home to one-fifth of the world’s fresh water, also suggested that it will enact laws this fall to become the first nation to outlaw bulk exports of water. Such a move could have long-term repercussions for the U.S., which has eyed Canadian supplies as a way to water its agricultural areas.