he Harbor Queen hovered near an oyster reef at the mouth of the Severn River Tuesday, as sixth-graders from Bates Middle School lined a rail at the stern.

Each grabbed an oyster shell covered in baby oysters, or spat, and after a short goodbye poem chucked the tiny creatures into the water.

The Bates students took a field trip Tuesday that was the final step in the Annapolis Maritime Museum and Park’s year-long Oyster Education Program.

Education Director Sarah Krizek said the program is focused on the Eastern oyster. In the winter, the museum goes out to four middle schools, where students build a model of the oyster and also complete a dissection. The museum raises baby oysters, and students stay connected with the spat during the year through a blog. Then, in the spring, it is time to plant oysters.

On the boat Tuesday students also learned how to measure salinity and dissolved oxygen, calculated the approximate distance between City Dock and the reef, counted the average number of spat on a shell, and learned about the other organisms that make their home among oyster shells.

Then the students traveled to the Ellen O. Moyer Park at Back Creek, the museum’s second campus, to hear from a Chesapeake Bay waterman, learn about the effects of different methods of oyster harvesting, and about how oyster reefs affect shoreline erosion.

“We teach them that oysters are beneficial to the Chesapeake Bay for multiple reasons. They help to filter the water, they also serve as a buffer, they serve as a habitat, and they provide jobs for people,” Krizek said. “So we’re trying to teach them it’s not just one thing we’re looking at, it’s this ecological point of view, that everything is intertwined. And we also try to teach them they can do something too to make a difference.”