Roughly a half mile off the west coast of Hawaiʻi Island, intriguing netted structures rise just above the surface of the deep blue waters. If you look carefully, you can see the triangular shapes from the shoreline or from the windows of planes transiting the nearby Kona Airport.
What are they? They’re the face of a developing open ocean off-shore aquaculture industry in the Hawaiian Islands.
Blue Ocean Mariculture is the only commercial offshore finfish aquaculture facility in U.S. waters. It uses these submersible sea pens to raise Hawaiian kanpachi (almaco jack or kahala) in its natural environment. The fish has caught the eye of chefs worldwide due to its taste, quality, and versatility. And beneath the water’s surface, it’s also caught the interest of Hawaiian monk seals in the area.
NOAA Fisheries is collaborating with Blue Ocean to evaluate observational methods and tools, such as remote cameras and artificial intelligence, to study these seals’ behavior around the pens.
Innovation and Artificial Intelligence
This regional joint pilot study is one of the ways NOAA and Blue Ocean are innovating together.
“As managers of protected marine species, we need to understand their behaviors in order to best protect them,” said Tori Spence, aquaculture coordinator, NOAA Fisheries Pacific Islands Regional Office. “Our project explores whether we could use a multi-faceted, technology-enabled monitoring approach to understand potential interactions between endangered Hawaiian monk seals and mariculture net pens.”
During the initial phase of the study, the team evaluated the effectiveness of using underwater video cameras to collect footage and using AI to analyze the data.
They mounted four underwater cameras on different areas of the pens. The cameras collected more than 700 videos, which were cut into 10-minute clips for AI analysis. NOAA Hollings Scholar Haley Durbin worked with an AI program and created an algorithm to analyze the video data and identify Hawaiian monk seals. Next, the team categorized and logged the seals’ behaviors based on the footage.
Using AI, Durbin automated and shortened the time-consuming process to review footage. They identified single monk seals in 103 of the clips and multiple monk seals in 42 of the clips.
They also identified four primary behaviors:
- Attempting to catch a fish
- Investigating the net pen
- Swimming by the net pen
- Other
“The video data has been really enlightening. It has reinforced the reliability of Blue Ocean’s staff observations and given us a closer look at what’s happening underwater,” said Kristina Dauterman, resource management specialist, NOAA Fisheries Pacific Islands Regional Office.
“Having a better view, and understanding, of seal behavior will help us and Blue Ocean recommend and implement the best possible measures to protect against potential impacts,” she added.
Gear Redesigns and Modifications
While the study is ongoing, the team is already generating useful data.
Thanks to the video footage, they identified seals repeatedly heading to the bottom of the pens where they could find dead or dying fish. The clever seals would then pull pieces of those fish through the netting to eat.
To prevent this, Blue Ocean introduced a special collection cone inside the pen to catch dead fish. The goal is to keep the fish outside the reach of hungry monk seals or other predators until the offshore crew removes the fish.
“This is a great example of adaptive management. Through the ongoing camera monitoring, we’re able to see if the cone is effective at reducing monk seal feeding attempts,” Dauterman said.
The footage also revealed how seals were obtaining fish through different portions of the pen netting. In turn, Blue Ocean is re-engineering the pen structure to accommodate smaller size mesh netting, which it plans to debut within the coming year. This will further reduce predator access to the kanpachi. Once installed, we’ll continue camera monitoring and analysis to evaluate if the new net is effective and recommend enhancements based on our data.
“As a pioneer in open ocean finfish farming it is essential that we continue to use advancements in technology to provide the best environment for our fish and for the waters we work in,” said Tyler Korte, Blue Ocean. “Collaborative efforts like the monk seal study with NOAA have enabled us to adapt our operation and continue to grow with the health of our fish, our oceans, and our community guiding our business.”
Future Applications
The pilot study, which is funded through 2025, has demonstrated promise on multiple levels—from AI integration, to collaboration, to species protection. And it builds on protective conservation measures Blue Ocean previously put in place addressing monk seal interactions.
“Aquaculture is a millennia-old practice, but it’s relatively new in U.S. commercial fisheries,” Spence said. “Our priority is to support cutting-edge science and research so that the industry can continue developing and evolving in a way that’s sustainable and protective of marine species, like Hawaiian monk seals.”
Research projects like this are critical to our science-based management. They demonstrate the value of partnerships between science, management, and the seafood industry. They also have widespread application in this growing industry—helping chart the path and inform environmentally sound aquaculture across the United States.
