Surveying vernal pools to document amphibian life was a regenerative way of witnessing spring, but the experience grew in meaning when its results had a tangible effect on how local planners considered the value of open space. Taking inventory of the Hudson River’s water celery beds (a type of subaquatic vegetation) was a good excuse to spend a summer morning in a kayak, but when the numbers reflected measurable facts about water quality, my connection to the river became stronger.

All of these endeavors in citizen science may also be steps toward what William H. Schlesinger, president of the Cary Institute of Ecosystem Studies, calls “translational ecology,” a response to the need for ecologists to find ways to deliver their information to the public and to policy makers, and to familiarize ordinary citizens with scientific research, so they can better grasp its implications and imperatives.

Besides, as so often happens in the natural world, when you learn something about the immediate subject at hand, a larger lesson plan creeps in. As Chris Bowser, an environmental scientist and educator who manages the Hudson River Eel Project, observed, “One of the great things about studying eels is that by paying attention to eels, we are paying attention to the entire ecosystem. Eels rely on oceans, estuaries, streams and entire watersheds. They’re found in farm ponds and in city creeks. They are the perfect ambassador for the entire ecosystem because they live the interdependence that environmental scientists like to point out.”

For me, that’s reason enough to look to the eels this April, to put on the waders and step into the icy stream. Reason enough to check the net, to count the eels and weigh them. Reason enough to note cloud cover, precipitation, the temperature of the air and water, the clarity and conditions of the tide.

And while observing and documenting these data points, I will also witness the more elusive mysteries of eel migration. Though completely translucent, glass eels reveal little about themselves. If you look closely, you can see their tiny eyeballs and hearts. But counting them is like trying to count something that is nearly invisible. How is it possible to hold something in the palm of your hand and still know so little about it?

Considering this small fish with such giant inscrutability, I wonder if for all the reasons there are to count eels — or bald eagles or jellyfish or monarch butterflies — it is this convergence of the known and the unknown that most engages the human imagination. And I am amazed anew at the paradox that our sense of place is derived from everything we know — along with everything that causes us to wonder.