Are you an eighth-grader who wants to spend high school studying marine biology, learning theater arts, or delving into the urban environment? If you do, there’s a New York City public school for you.

Mayor Bloomberg and the schools chancellor, Joel Klein, announced yesterday that 52 additional small schools would open in September.

The new schools, some of which will be in new and leased buildings, and some of which will share space with other schools, will offer personalized learning environments and academic rigor that most large high schools are unable to provide, Mr. Bloomberg said. He said their students would also benefit from partnerships with local businesses and cultural organizations.

“The early results are nothing short of astonishing,” Mr. Bloomberg said as he presented statistics that buoyed the small-schools initiative.

In the last school year, average citywide attendance was 83%, while at small schools it topped 90%. On average, 68% of city ninth-graders were promoted to the tenth grade, but at the small schools 93% of ninth-graders were promoted to tenth grade.

Mr. Bloomberg said attending a small, themed high school doesn’t guarantee a certain career.

“Just because you go to a school with a theme doesn’t mean you are restricted in your entire life to going into that occupation, into that industry or that interest as a career,” the mayor said. “Quite the contrary. When you get a good education, your opportunities are broader. They’re not narrower.”

He continued: “Don’t confuse the fact that the theme is, let’s say, sports management. Everybody that goes to that school is not going into sports management. … My guess is, the more successful that school is, the smaller percentage will go into that, because these kids will have their horizons expanded, their educational opportunities after high school will be much greater, and they will discover a while world out there they would otherwise never see.”

The principal of the newly named Rachel Carson School of Coastal Studies, Joanne Pierre, said the school would work together with the New York Aquarium to help students – and their families – learn about marine biology.

“I think there’s a need for a school focusing on science,” Ms. Pierre, a licensed scuba diver, said.

The educator chosen to be the first principal of Explorations Academy in the Bronx, John Nassivera, said small schools are part of the answer to an improved public-school system.

“Diversity is the answer to success,” he said. “The small schools are not the complete solution, but they are part of the solution.”

Politicians and union leaders expressed mixed opinions of the mayor’s announcement.

The president of the principals union, Jill Levy, said the creation of small schools in the past two years has led to overcrowding in large high schools.

“Let us hope that the Department of Education learns from its mistakes this time around,” she said.

The president of the teachers union, Randi Weingarten, praised the department for placing nearly one-third of the new schools in underutilized middle schools or new spaces. But she said: “The system is not going to have a real solution to its space problems until the mayor makes a commitment to fight for the resources we need under a comprehensive capital program.”

The chairwoman of the City Council’s Committee on Education, Eva Moskowitz, said the city is trying to combat “abysmal academic failure” in its high schools. But she said, “The question that parents and the public need answered is: Why is it going to work better this time around? My own belief is that neither the size nor the theme is as important as having highly qualified teachers and dedicated instructional leaders with real decision-making authority.”

The new schools will bring the number of small schools and charter schools in the system created under the Bloomberg administration to 157.

The mayor suggested that students eager to learn more about small schools could dial 311.