Mariner and North Fort Myers high schools were among six Lee County schools receiving a “grade” of A from the Florida Department of Education this week.

It was Mariner’s first A. Last year the two West Zone schools earned a B.

“It was great news yesterday,” said Mariner High School Principal Brian Mangan on Thursday. “I know this is a clich but it was truly the teachers, support staff and students (who earned the grade.)”

Teachers began concentrating on the school’s improvement plan early last school year, targeting areas in need of special effort. Teachers and other personnel concentrated not only on subjects but also on developing relationships with students to better assess individual strengths and weaknesses, Mangan said.

That made them better prepared to take the exams on which the state’s school grades are based, he added.

“It helped translate our focus to the classroom,” Mangan said.

Countywide, high schools saw an overall improvement in grades received, according to information released by the Florida Department of Education Wednesday.

Six schools received a grade of A – up from four – while a total of 13 earned enough “raw score” points to earn the top designation, Lee County School District officials said in a prepared statement announcing the results.

“The reason only six of the 13 were awarded an ‘A’ grade is because the high school grading system has two specific rules regarding the performance of the lowest 25 percent in reading and the at-risk graduation rates. If either percent falls below the required level, then a high school cannot earn an ‘A’ even though they have earned enough total points,” the release states, adding seven received a letter grade lower than earned because there was not “sufficient growth among lowest performing students.”

“When looking at the total points earned by our high schools, it’s very encouraging news to see 13 schools worthy of an ‘A’ grade,” said Dr. Joseph Burke, superintendent of schools, in a prepared statement. “We realize there is work to be done for the seven schools that were dropped from their ‘A’ grade and we started addressing those areas well before the grades were released, especially high school reading.”

In total, 87 percent of high schools countywide earned an A or B grade as compared to the statewide average of 78 percent, the release states. Districtwide, all grade levels, 90 percent of district schools earned an A

or a B. Fifteen schools improved by one grade level and two schools improved by two.

“It’s clear the foundation is there for our high schools to shine above others, and with our focus in these areas we’re ensuring all students are on a path to increased academics,” Burke said. “This is good news for our

district, our students and our community – and we will continue to work hard to move all our schools toward increased academic achievement.”

Cape Coral High School, Ida S. Baker High School and Oasis Charter High School, which only received points for the FCAT portion of the grading system for 2009/10, each dropped from an A to a B for 2010/11.

Only one school in the county received a D – East Lee County High School, which had dropped one letter grade. South Fort Myers High School dropped from a B to a C.

High school grades were released late for various reasons, officials said, adding “there are various components used to calculate the grade over and above the Florida Comprehensive Assessment Test. Those include points for participation and performance in advanced courses, points for graduation rates of both regular and at-risk student populations and performance on college readiness examinations (SAT, ACT, and CPT).”

The state has issued school grades since 1999.