Tell us about the Maine Center for Coastal Fisheries.
Anderson: The MCCF is a small nonprofit based in Stonington, Maine, founded about 16 years ago by Robin Alden, a very charismatic leader in marine resource management. The MCCF characterizes our work in three discreet but integrated initiatives: one on collaborative research, another on collaborative management, and a third on collaborative education. Intentionally, the word ‘collaborative’ is in everything that we do. It’s very similar to Manomet’s approach, where we realize that if we all work together and find the right partner institutions or individuals, we can probably get more done. The organization’s overall goal is to help sustain commercial fishing and the communities that depend on it in eastern Maine.
Why alewives?
Thalhauser: I work with species that either do or could potentially have some shared responsibility and co-ownership of the management of our natural resources. Alewives and clams are the two species in Maine with a formal structure where municipalities apply local knowledge to management which is shared with the Maine Department of Marine Resources.
Alewives are a river herring species that spend most of their lives out in the open ocean migrating and commingling with Atlantic herring. They swim up and down the coast from the Carolinas to Canada, and then, like salmon, return to their home ponds to spawn and restart the cycle. They are an overfished species along with many other herring species and were also negatively affected by the blockage of the fish passages into their spawning grounds. Since they have site fidelity, meaning they return to the place they were born to spawn, their home pond is a critical, instinctual connection in their life cycle. We can’t put a dam in one place and expect them to swim to another pond to spawn.
Alewives are a depleted species, but one of the best things they have going for them is how resilient they are. You can remove one of these dams and stock the fishery, even at very low levels, and they’ll return. In places like the Penobscot, we’ve gone from almost zero fish to millions of fish in less than a decade. This success is one of the greatest assets this species has, as people can understand how actions put in place have had a tremendously positive impact on alewife populations. It’s a fishery on which you see immediate impacts. When we’re talking about groundfish, like cod, it could take decades for people to be able to see any impacts.
It simply takes boots on the ground to steward these fisheries and keep them coming back. That’s where the co-management piece comes in. In Maine, we’re lucky enough to have a system in place to incentivize that stewardship and get folks at the right scale working on bringing these populations back.
What is environmental DNA or eDNA and how are the MCCF and Manomet using this technology?
Thalhauser: A big unanswered question whenever you’re thinking about managing or harvesting a fishery is looking at the productivity of the system and saying, “With x-amount of fish spawning, how does that system look years later and how does productivity tie into food availability and habitat?” All those different factors make one pond able to produce a lot of fish with just a few adults going back and others being somewhat of a tightrope walk.
For adults, we count them as they enter the ponds by visually counting fish or in some systems, with the help of video or other technology. Counting juveniles in the pond is not so easy. We use a purse seine, a net that we circle and then purse up at the bottom to catch the fish. We do these at night when the juvenile alewives are all dispersed in the pond (they hide during the day to avoid predators). We’re starting to get density estimates of the juveniles compared to how many adults came back and are looking at that productivity.
eDNA is a new tool for fisheries research and management. It started as a presence versus absence tool, wherein you could take a sample of water, analyze it, and detect the DNA of certain species using that water. You could also learn about whatever else was using that area, from frogs and other aquatic life to plant debris, and even people. This technology has advanced to the point of being able to see how genetic material has changed over time, and we can even see if the numbers of river herring have increased or decreased in an area.
To be effective with co-management, you’ve got to know what’s happening at the ground level. The use of eDNA could be a great tool to better estimate the number of fish returning to an area and better understand what local populations look like.
Manomet’s Anne Hayden is also looking at how this tool can be used; we worked together to design a monitoring program and collect samples. After I go out to purse seine and sample ponds, Anne and I will go out in the canoe and sample those same places, so we can compare the findings.
What does the future of fisheries look like?
Anderson: I’m excited about ecosystem-based fisheries management. In its simplest form, we can better manage how we fish and how we control fish populations. We need to think about more than one species at a time. We should think of species as players in an ecosystem that interact with one another. Each species interacts with the ecosystem uniquely, such as when temperature or acidification change; many species may react similarly, others may react differently. We also try to think about how we can better understand the interactions of species with their environment and one another, as well as humans and how we are part of that ecosystem. It ends up becoming pretty complicated.
It’s fascinating to think and talk about, but it’s very hard to study, because each one of those threads you pull, you find it pulls another one, and then it pulls another one. It’s going to take a lot of information, a lot of talent, and information management, modeling, maybe even artificial intelligence, eventually.
