Chutes and fish ladders

Helping the fish migrate along the Bronx River. 
Helping the fish migrate along the Bronx River.  Photo Credit: Joan Marcus

If the imminent changing of the seasons is getting you down, consider the situation of some New York fish.

The alewife herring were accustomed to making spring pilgrimages from the ocean to the Bronx River (and trips back in the months after), until human construction started getting in the way.

The city Parks Department and advocacy group Bronx River Alliance have tried to change that, work that continues all year.

amExpress discussed the subject with Maggie Scott Greenfield, Bronx River administrator for the Parks Department and executive director of the Bronx River Alliance. The Bronx resident talked “fish ladders,” giant tanks full of herring, and why rivers are important, plus the strong forces that guide fish year after year: “It’s pretty dramatic voyages that these fish take.”

Tell us about the herring.

So, alewife herring are one of the native fish that were once so abundant in eastern rivers like the Bronx River that people talk about how during spring migrations the river used to run silver with fish.

How long ago was that?

Three hundred years ago or so. Early colonial days when people were settling in the area before the dams were built for mills and pollution took a toll on the rivers. We think about the salmon runs out west in Alaska, but we used to have runs like that in our rivers, too.

What does a run mean, exactly?

The alewife herring live out their lives in salty sea water and come back to their home rivers to spawn and have their babies. So that’s what the runs are for. It’s kind of an annual rite of spring, it’s a time for the fish to come back and have the next generation of fish.

But when the dams were built on the Bronx River, those blocked the way and fish could no longer reach the fresh parts of the river they needed to get to to spawn. 

To bring back these native fish, we have to develop a bypass for the fish to get around those dams and that’s called a fish ladder. So we work together with the parks department to build a ladder on the downstream-most dam on the river.

Talk us through the “fish ladder.”

It’s not actually a ladder, it’s more like a couple of water slides built to certain specifications in terms of flow and the angle so that the fish can actually make their way up it. They kind of wriggle their way up, and then there’s a resting pool and then they turn and go up the last bit of the chute, which is called the fish ladder. 

And they do this on their own?

Yeah. They’re just biologically programmed to do this.

And where’s the dam we’re talking about?

The 182nd Street dam right at the southern boundary of the Bronx Zoo. It’s a popular park called River Park; there’s a waterfall that people love but of course that’s the dam that the fish can’t get around.

So we open up the fish ladder, but the problem is that there’s not many fish coming back anymore because we’ve broken that cycle. So what we do is we work together with the parks [department] and the Connecticut Department of Energy and Environmental Protection, and they bring down fish in the springtime that have returned to a creek in Connecticut that has abundant fish. And they bring 400 fish or so that are just about ready to spawn, and they bring them in this big tank on the back of this truck and release them into the Bronx River. When they spawn, those babies then are sort of imprinted on the Bronx River and the Bronx River is their home river. By doing that, we help to restart the whole cycle of migration. We’ve been doing this for three years, and we think next year we might start seeing some of those fish coming back to the Bronx River.

Right now, where will these fish be?

Out in the open ocean now.

What work is there on your end at this stage of the year?

In terms of our ecological work, we shut down the fish ladder in the summertime after the last fish would reasonably have used it. We just want to protect it from debris.

Mostly, the work is about cleaning up the river and restoring its habitat so it’s a good place for these fish to live. Making sure there’s healthy plants and vegetation, shade on the river that help the fish spawn and mature and be a happy place for them to come back to.

We have a conservation crew working to fight invasive plants. Once they remove the invasive plants, they plant native plants in their place which tend to hold the banks better. That contributes to a healthy river. They also work with volunteer groups: tree-planting activities and invasive [plant] pulls throughout the seasons. The spring and fall are big tree planting times.

Are you from New York originally?

I grew up in Tennessee. I actually grew up on the Tennessee River.

How does that compare to the Bronx River?

Well it’s a little different, the Bronx River is, you know, it’s a smaller waterway, but it’s got a lot more people around it. It’s that much more important for the people who live here to have access to a healthy ecosystem and beautiful parks and trails. 

This interview has been edited.

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