The Seward Park Co-op held elections for its board of directors yesterday. Jodi Zagoory, Carol Anastasio and Michael Tuminia unseated three incumbents. The only current board member up for election who prevailed was Carlos Rosada. Fran Marino, Lee Slater and Michael Kansco were voted out of office. During the past year, shareholders have grown increasingly concerned about the Co-op's financial health, the management of retail space it owns along Grand Street and a controversial decision to raise sublet fees. There are about 1700 apartments in Seward Park's four towers, which stretch from Essex to Montgomery Streets. The top vote getter, Zagoory, received 533 votes.