Harlem elementary schools are “hemorrhaging” students, according to a new report by the Center for New York City Affairs at the New School.

Just 37 percent of students who live in the Harlem portion of District 3, which also includes the Upper West Side, attended their zoned elementary schools last year. Meanwhile, 36 percent attended charter schools and 27 percent attended other public schools.

Even more striking, perhaps, is the breadth of public schools the area’s 2,447 elementary school-age children attended — roughly 176 in all, according to the Center’s analysis.

With so many children in Harlem attending charter schools or Upper West Side district schools, enrollment in the area’s zoned elementary schools has withered, the report found. Five of the seven zoned schools in the Harlem part of the district now have fewer than 300 children, and three have fewer than 200. Declining rosters mean smaller budgets, the authors note, and the higher-need children are the ones more likely to stay in the neighborhood.

A tense rezoning debate shook the Upper West Side last fall, as parents fought a decision to move some students from the coveted but crowded P.S. 199 to P.S. 191, a lower-performing school. Some residents of District 3 felt that a close look at Harlem’s schools got lost in the shuffle.

The District’s Community Education Council recently held a summit to focus specifically on Harlem.

“This is a door-opening,” said Kim Watkins, a CEC member who organized the event. “This is a cultivation of parent activism and community bridge-building so that we can figure out how to level the playing field.”