Innovative solutions to restoring the Papahānaumokuākea Marine National Monument
Fung Fellows teamed up with the Papahānaumokuākea Marine Debris Project to remove and reimagine abandoned fishing nets
Looking to tackle an exciting and impactful technical challenge, Anjana Saravanan (Mechanical Engineering), Aditya Vunnum (Molecular & Cellular Biology), Joelle Siong Sin (Industrial Engineering & Operations Research), Kelsey Leet (Environmental Science), and Elena Mujica (Bioengineering) partnered with the Papahānaumokuākea Marine Debris Project (PMDP) — a non-profit that aims to protect the sensitive wildlife and critical habitats of the Papahānaumokuākea Marine National Monument (Northwestern Hawaiian Islands) from the threats of marine debris — for their semester-long Fung Fellowship project.
The challenge: Abandoned fishing nets — or ghost nets — populate the Papahānaumokuākea Marine National Monument and endanger the health of the coral and marine life. These make for a difficult and time-consuming task of removal because of the size, weight, and entanglement of the nets.
Their solution: Design a more efficient cutting and tensioning tool for ghost net removal underwater to make massive net bundles — some greater than 1000 lbs — easier to remove and safer for divers to maneuver.
Their solution, however, doesn’t end there. The team also took into consideration both what to do with the nets after removal and how to help the ecosystem recover.
Here, we caught up with the team to learn more about their proposal and their trip to Hawaii to see their work put into practice.
What is ghost net removal and why is it important?
Ghost net removal is the removal of abandoned fishing nets. In the Papahānaumokuākea Marine National Monument, many ghost nets and other derelict fishing gear come to rest in coral ecosystems and pose serious dangers to the health of the coral and to marine species.
The removal of these nets is incredibly difficult as they rest on corals in large bundles that can weigh up to tens of thousands of pounds. In order to remove these nets divers will cut them into smaller sections and manually load them on small boats. Removing these nets is crucial to protecting an ecosystem that is home to countless endemic species and great biodiversity.
What is your proposed tool, how did you come up with it, and how will it help to address the problem?
Our proposed tool primarily focuses on creating tension. It consists of paired 3D-printed anchors and lead screws along with cinch ropes.
The idea is to create tension in steps, first by cinching off a central section of the bundle and then pulling axially within that section. This will help address the problem by giving divers a way to not only create tension but hold it underwater hands-free, so they can use a wire saw in conjunction with the tool.
What are your other proposals to assist in addressing the larger issues with net bundle accumulation?
When looking to increase the rate at which net bundles are removed by designing a tool that improves efficiency, we wished to ensure that the entire life cycle of the recovered nets is considered. At present, the removed nets are incinerated to generate electricity for the islands.
We proposed that the nets instead be donated to indigenous artists for exhibits in community spaces.
This ensures that the nets are utilized in a non-consumable fashion that honors local heritage and culture while educating the community on the net removal process.
We also wanted to address the degree of coral death in the National Monument as a result of the net bundle accumulation. In order to help restore the coral, we connected PMDP with the Coral Resilience Lab to begin discussion around the Restore with Resilience Program.
The program is designed to transplant thermally-tolerant corals native to different reefs in Hawaii. With work already underway around Oahu, the program would help ensure that the monument can recover from net damage with additional safeguards against bleaching events caused by global climate change.
What did you and your teammates do in Hawaii this August?
In Hawaii, we tested the performance of our designs underwater against the nets that the PMDP team most commonly encounters.
The initial testing of our design was successful and the whole team was so grateful for the opportunity to field test our work. The device improved the rate at which the divers were able to sever the net and was successful at creating tension for easier cutting under water.
We also discovered the ways in which we can improve the device which is a further sign of a successful campaign.
Now, we’ve passed on our final prototype to the PMDP team for them to develop further and continue testing in the field. They are currently on a month-long expedition and they will test the tool further while they are there.
What did you learn through the process and how did the fellowship enhance that learning?
We learned a lot about the benefits and difficulties of working within an interdisciplinary team. Since all of us are from different majors programs and different professional backgrounds, we all had to learn how to navigate working with people outside of our field of study to produce an effective prototype.
The fellowship also gave us a place to meet a very diverse group of students and get to know each other a lot better as we worked through our project.
Ultimately, what did you hope to accomplish with this project and did you achieve that goal?
With this project we hope to increase the ease and efficiency at which the net bundles are removed from the monument while prioritizing diver and ecosystem safety. We also hoped to improve the method of which the recovered net bundles are utilized and instill a partnership that will prioritize the recovery of coral communities.
Testing our prototype proved that our concept and execution were strong and this is the first step towards building a finished tool which will help the PMDP divers remove ghost nets at scale. We accomplished our objective and we’re excited to see where the team at PMDP takes it from here!
Kelsey Leet (Environmental Science), Anjana Saravanan (Mechanical Engineering), Aditya Vunnum (Molecular & Cellular Biology), Joelle Siong Sin (Industrial Engineering & Operations Research), and Elena Mujica (Bioengineering)
Papahānaumokuākea Marine Debris Project — Kevin O’Brien and James Morioka
Edited by Veronica Roseborough.