Science by the Shore
Researchers study invasive species and plastic pollution to promote healthy aquaculture
Aquaculture is an economic field that is too often overlooked, not only historically but as a potential booming industry that has many needs and concerns to sustain and grow.
Last summer, the MyTurn program worked with the Nature Conservancy for an innovative youth mural internship, sending its participants to meet scientists from the University of New Hampshire: Taja Sims-Harper and Kelsey Meyer. The two doctoral candidates so inspired the creative interns that when the murals were finished at West High they were chock-full of aquatic life.
Sims-Harper and Meyer took time to sit with 603 Diversity to share how their studies seek to improve coastal habitats along Great Bay and beyond.
The following are edited conversations from earlier this summer.
KELSEY MEYER
Kelsey Meyer is a doctoral student in the College of Life Science and Agriculture’s biological sciences: a marine biology Ph.D. program. She currently spends a lot of time traversing Great Bay in a small boat, collecting invasive green crabs, baiting traps and monitoring tiles for oyster spat.
603 D: Where do we begin? What and how do you study for your Ph.D.?
Meyer: Green crab stuff. I pull their guts out to dissect what’s in their stomach.
My Ph.D., essentially, has four foundations, one of which is the social science aspect, where I send out a survey to all the NH oyster farmers inquiring how green crabs are affecting their farms. This is important because I want to know what the farmers’ interests are and what their concerns are so that I can better direct my research.
In addition to this, for the last two years, I have trapped green crabs at oyster reef areas and oyster farms to assess where they are congregating. I was always curious about this arm of research, and right before I started my Ph.D. program, I was helping with my now advisor’s project on spat (oyster larvae) collectors and noticed there were never really a lot of spat, but there would usually be green crabs in the cages with the collectors.
This sparked my interest: How green crabs may be affecting natural oysters, and are green crabs affecting the local oyster farmers and the oyster industry in New Hampshire? There has not been a lot of work on this in NH estuaries, but there is the NH Green Crab Project, which is educating the public about green crabs, using citizen science, and tracking their molting/finding potential markets to utilize this invasive species.
603 D: How does this relate to their guts?
Meyer: I would extract DNA from their stomachs and send it to the UNH Genome Center, and they can tell us every single thing that is in the DNA, which is how we assess their diet. What the genome sequencing revealed was that they are scavenger types, like if they can eat it, they will. But out of the common
organisms in their diet, oysters were not on the top of the list.
The Chesapeake Blue Crabs may be more of an issue due to climate change. Warmer waters are really changing how an ecosystem functions, as well as ocean acidification — this can make the shells softer and more vulnerable to predation (the preying of one animal on another), especially smaller oysters when they interact with large crabs.
The last foundation of the project is green crab predation on oysters using various oyster size comparisons to crab size combinations.
603 D: Now, how does this relate to the aquaculture industry?
Meyer: The bottom line is green grabs are eating oysters to a certain degree. There are other shellfish that are more vulnerable like mussels, soft-shell clams. NH’s oyster farming is growing — it’s not as large as Maine or Massachusetts — but it is becoming a bigger industry and has a lot of potential to yield a healthy income for many New Hampshirites as well as providing ecological benefits. I want to help this industry grow, whether it is with the dissemination of information or assisting in research.
603 D: What are some of your hopes for the future or a fantasy regarding this work?
Meyer: Something that would be very cool … if green crab harvesters were to partner with oyster farmers. That way they can help clear out some of the green crabs on the farms. Green crab harvesting can provide a food source for humans, bait for other industries and even compost or fertilizer. It is a natural product that can be utilized in many different ways. I would also like to add: Support your local oyster farmers!
603 D: Are you staying in New Hampshire when your project is done, and when will that be?
Meyer: I want to stay in New England, and I have one more year left.
TAJA SIMS-HARPER
Taja Sims-Harper is also a doctoral student in the UNH marine biology Ph.D. program. She conducts her research on microplastics in oysters and other marine life in Great Bay in the lab of Bonnie Brown, professor of ecological genetics and the chair of the Department of Biological Sciences. She earned her bachelor’s degree in marine science from the University of Maine.
603 D: How does your work intersect with that of Meyer’s?
Sims-Harper: A lot of our studies cross over. As far as when we collect water samples, what we can use them for, when Kelsey collects green crabs, she gives me a few, for instance. What I am working on is documenting the amounts of microplastics within the oyster populations and what the effects on the oysters and their consumers are.
I also work with NH Fish and Game. They gave me fish to see if there were plastics in the fish as well. Just to get a sense of how much plastic is present in these specimens and how it affects them.
603 D: Why are oysters so important?
Sims-Harper: Oysters are the filtration system of our local biomes. These studies we have been conducting are very important to my knowledge database, because I started my own oyster farm recently. Due to the demands of Ph.D. requirements, however, I had to expand my studies and add fish and crab into the observations to see if it was a food chain issue as well.
603 D: Could you illuminate some of how that works?
Sims-Harper: So, if fish ingest plastics, then crabs eat fish, then people eat crabs, it inevitably affects the whole food chain. What does this mean for each species in the food chain? We have found that the oysters do, in fact, have plastics in their body. Now we have to figure out how that affects humans, because we eat the oysters we’re studying.
One would think that the oysters we study in the wild are healthier than those we study which are farmed, but this is not the case, at least from a consumption perspective, as farmed oysters are tumbled. This means they are removed from the water for up to 24 hours to dry out a bit and so we can scrape off tunicates (little irksome creatures) and sponges (the alive kind). All of this is helpful in creating healthier oysters. Floating cages are integral in this process, which is a practice commonly used in other states that have a more teaming aquaculture economic sector. But for New Hampshire, common practice is still hindered by rules against floating cages solely for aesthetic purposes.
603 D: Studies in microplastics in marine life are common globally, but it is relatively new for the Great Bay. Are there tensions in this type of research?
Sims-Harper: We can’t run from plastics, so now we should study how it affects us.
603 D: In regards to the format of your Ph.D., how does it all fall together?
Sims-Harper: The first chapter is on collecting water samples from 2018-2022 to obtain a time series in order to establish a data set. I am looking for things like how much plastic, where is it accumulating, and then we are running modeling software, which can detail up to three days before and after the particle was collected, where it was going and where it had been!
The second chapter is comparing samples from the wild to samples that were farmed. I added samples from New Jersey and Maine to get a larger data set. Overall, we found that farmed oysters had up to 50% less plastics.
The third segment is the experiment. I am looking at depuration, a process which basically is putting shellfish in massive tanks of super clean water to see if they can filter out the toxins in their body. This process is usually reserved for shellfish, which are from regions containing nonpotable species or areas where they are not allowed to be farmed. I want to see if this process can be used to clean out plastics from the oysters.
603 D: This was so informative! Does anyone else have your back?
Sims-Harper: My mom is my biggest advocate. She reminds me a lot, even when I am in a big impostor mental state, that this is the stuff I am passionate about and that I have invested years into this work. She reminds me to finish the Ph.D. I started. She reminds me that I have my farm already, and she reminds me that this work and research I do will be disseminated back to my community and my people.
This article is featured in the fall 2024 issue of 603 Diversity.
603 Diversity’s mission is to educate readers of all backgrounds about the exciting accomplishments and cultural contributions of the state’s diverse communities, as well as the challenges faced and support needed by those communities to continue to grow and thrive in the Granite State.
