American eels have long been a culturally and ecologically significant species on Cape Cod and the Islands. But in the past few decades, the population of eels has been declining. Researchers at the Nantucket Conservation Foundation (NCF) want to know: by how much?
CAI’s Gilda Geist interviewed NCF’s coastal ecology research technician Jisun Reiner, who is heading up the Nantucket Eel Project.
Jisun Reiner This project is basically getting a census of eel populations that pass through Nantucket. Eels are amazing creatures, and they migrate from about February to May as glass eels, which are juvenile eels. They are like an inch long, really translucent. My partner Isaac and I went out into the field twice a week, and we had eel mops that were deployed. They look like big heads of hair and they're passive traps that glass eels will pass through to kind of take a pause on their journey upstream. And we would go out twice a week, shake out the mops and count the eels that were in there.
Gilda Geist And so you guys were out there counting, but also there was kind of like a citizen science, volunteer aspect of the study, right?
JR Yeah, that was a really big component of this project. There were two goals to the field project. The first was to get that census of glass eel migration at the four sites we had around the island. But the second goal was to connect people with this shared environment on Nantucket and to engage people in all of these scientific skills and the knowledge that they can learn from being out in the field. So we reached out to different community members and had a lot of people join us out in the field—all different ages and backgrounds. We had high school students, we had retirees, and people who had a lot of memories of eel fishing on the island back in the day.
GG Can you speak to the ‘why’ in terms of why it's important to count up the eels and whether their population is threatened here on the Cape and Islands?
JR Yeah, so their populations are at historical lows. The population of eels have started to decrease more significantly in the last 40, 50 years. And they face a number of threats. Overharvesting is a large one. Also contaminants and disease, dams, climate change which is changing ocean currents. So this project is especially important to get an idea of how many eels are present. And they are definitely really important for the food chain and also just very significant socially and economically.
GG Have you counted up any preliminary results yet?
JR We're still synthesizing all the data and looking at the correlation between eel numbers and tide and temperature and all these other environmental factors. But we definitely feel very positively about the numbers that we were getting, because we were only expecting to count about a dozen in the mop at each check, but we were getting, I would say, like an average of like 30 in each mop when we were checking, sometimes much more than that. So yeah, we're going to be distributing that data very soon once we analyze it.
GG Looking more broadly, what do you think is important about this study? What do you think the impact will be on the science in the region?
JR Getting to know the eel numbers is going to be important for understanding watershed health around the Cape and Islands, but I also think that an equally important result of this is going to be how aware people are going to be of their waterways, because people on the Cape and Islands, they are almost certainly living within a mile of an eel. And if people start to interact and see eels, whether through this type of project or through fishing, they become a real gateway into learning about nature, about history, about indigenous people, and learning about the interconnectivity of waterways. Eels are such a mysterious, elusive creature that I feel like this project is going to get people aware of how many mysteries there are in nature, and hopefully get them really excited about exploring those mysteries.
This interview has been edited for length and clarity.
