When Alley Moore was a boy, his summers were spent with his feet in the warm, shallow water of Tisbury Great Pond. His family has had a rustic duck-hunting camp on the pond for five generations and, throughout his childhood, family gatherings took place there each year.
“We would go out and get oysters, clams, and crabs, and we would put the oysters on the grill, and then boil up the crabs and the steamers, and we’d get some corn, and we would have a big party, multi-generation from grandparents down to the kids,” said Moore. The cabin didn’t have electricity until recently, so when the sun set, they’d light candles. “You could see the fireflies; you could see the stars,” he said. “It’s just magical.”
Moore, who is originally from St. Croix, returned to the pond every summer until he moved to the Island full time about thirty years ago. His love of the ecosystem eventually led to a job as a pond commissioner. He and the other commissioners, Johnny Hoy and Davis Solon, live near the pond. They were elected by the Riparian Owners of Tisbury Great Pond – the association of private property abutters – to monitor the body of water and determine when it’s time to open the tranquil pond up to the unruly Atlantic Ocean that sits on the other side of a thin barrier beach.
The reasons why they make this cut are as complex as the web of life that exists in both bodies of water, and as varied as the fluctuations of the seasons. The pond is typically opened four to five times per year and some of the many factors the commissioners consider in their timing include the level of the water in the pond before it’s opened, the fish that live and spawn in the pond, the salinity, and the nitrogen level in the water. When making the decision, the commissioners also occasionally check in with the Island’s conservation commissions, herring and shellfish wardens, and the Audubon Society.
The spring cut, which often happens in April or May, is a crucial one, Moore said. Rainfall collects, raising the pond’s level, and locals take note.
“We get various people calling us, asking, ‘When are you going to open the pond? It’s getting really high.’ People’s basements flood, and all sorts of things happen when the pond gets high, so we get a lot of feedback from the human constituents,” Moore said.
But the non-human constituents make their priorities known as well. “We have a group of herring that come back to the place of their birth, and they want to spawn in the pond.” The herring were born in the pond, left during a previous cut, and return to lay their eggs. When spring comes around, the herring approach. “They’re sitting out in the ocean, gathering in front of the pond in order to get in,” he said.
You can see them from the barrier beach, and, if you’re highly trained, you can also sense them in another way.
“Johnny Hoy can smell them,” Moore said with a laugh. What do they smell like? “It’s kind of like fishy watermelon, I think.”
The summertime cut decision is based on factors including nitrogen runoff, which heats up in the warm weather. Nitrogen,
a major environmental threat to the
Island’s fresh water, comes from septic-system wastewater, lawn fertilizers, and other sources. When all the Island’s homes are full in the summer, the ponds get maxed out on nitrogen, which has to be flushed away.
This timing lines up with the schedule of the pond’s blue claw crabs, which are desperate to get to the ocean. When the cut is made at the end of July or August, “you’ll see thousands of blue claw crabs start to gather at the opening,” Moore said. “They seem to smell that little bit of salt water. Then, as soon as it gets open, you’ll see them flying out.” Female blue claw crabs in a pond need higher-salinity ocean water to spawn and hatch their eggs, as the higher salt levels are required for their larvae to develop properly.
Come fall, the herring and bait fish in the pond need to get back out to the ocean to complete their life cycle. In winter, and throughout the rest of the year, the oysters and clams in the pond need infusions of salt water for a few reasons: seawater carries food sources and minerals needed to build their shells.
Occasionally, due to factors such as severe storms or high winds, Tisbury Great Pond opens to the ocean naturally. But it’s better for the entire ecosystem if it happens more regularly. The process of making the cut involves an excavator and a man named Jay Sonia to operate it skillfully. “He’s really good at it,” Moore said.
Once they’ve been cleared by folks at Audubon that the ground-nesting birds are safely out of the way, the process can begin. They mark the area they’re going to cut, and dig a trench without breaking through to the water on either side of the barrier beach. Then, once the trench is dug, they dig out the sand walls and the water flows. This current can be incredibly strong, and it’s important to stay away. Accidents have happened, and people have died. Visitors shouldn’t go to admire their work while it’s happening, but anyone who visits the pond throughout the year and sees the ecosystem, peaceful in its harmony, can know that some considerate citizens are working behind the scenes, all year round.
Moore is caring for a part of the Island that has been important to his family and to many others. “It’s always been a place of refuge from the real world, and one of the things I love about it is that it really hasn’t changed much since when I was a boy,” he said. “The natural beauty of the place has stayed consistent over that period of time.” Moore’s two daughters were born on the Island, and they’ve grown up around the pond. They now go out there to fish and kayak with their friends.
To Moore, it seems as if the pond is somehow always the same and always changing. “It’s a place of real freedom,” he said. “It’s just moving sand.”
