What happens when a fish missing for 200 years suddenly returns?
This is the central question of my doctoral dissertation. And it's more complicated than it seems.
The American shad isn't the most well-known fish. You won't find it on seafood menus, and you mostly wouldn't expect anglers to be standing shoulder-to-shoulder on a river's bank for the chance to reel one in. It's an average fish in most every sense of the word. Think of what the most basic-looking fish looks like. There. You just pictured a shad.
But the American shad is special in at least one regard. In 2017, it reappeared in a river in New Jersey where it had been missing for nearly 200 years. This river, the Musconetcong, loving called the Musky, runs through one of New Jersey's most active agricultural regions, an area called the Musconetcong Valley with a rich farming history going back centuries. The Musky was dammed to improve the supply of water to these farms, ending with upwards of 20 dams within in a 30 mile stretch. This was great for a growing demand for freshwater, but it meant the end of American shad there.
The shad is a lot like a salmon. Both are fish that leave the open-ocean every year to swim upstream into smaller rivers for a chance to spawn the next generation. For some, this journey is hundreds of miles, much of which is against the current in search of the place where they themselves were born. But in a state as developed as New Jersey, this journey back upstream is often impossible. The dams built along the Musky meant the shad were blocked and would never return.
However, in 2016, the second of two old and obsolete dams were removed from the lower part of the Musky. Within a year, American shad were found there, looking once again at the Musky as a place to spawn. This means the incredible work led by community organizations, universities, and government agencies to restore the river to its natural state is headed in the right direction. It also means more work is to be done before the American shad makes a full comeback and we finally see another generation of Musky shad.
I'm currently working alongside the wonderful Musconetcong Watershed Association and the New Jersey Department of Fish & Wildlife to determine what else is needed to make the Musky shad-ready. Is removing those old dams enough? The river has changed quite a bit in the past 200 years, so it's difficult to be certain just yet. For now, we're monitoring water quality, the river's behavior over time, and finding ways to undo some of the damage of past development. And we're on the lookout for shad, too.