The ocean is a vital source of the world’s food, income and, increasingly, sustainable energy. But competing priorities among the industries that use the ocean make it difficult to make informed decisions about how best to share this vast resource. 

To address this, Cornell researchers have used marine spatial planning – a method that aims to evaluate the use of ocean space and to balance the needs of the ocean’s users with responsible use of its resources – to map areas off the northeastern coast of the United States. In doing so, they have pinpointed an optimal location to site an offshore aquaculture farm powered by waves, offering a model for sustainable development that minimizes conflicts among marine industries.

Their study, published in January in the journal Renewable Energy, is “the first that rigorously looked at, in the case of the Northeast, the potential conflicts that might exist with existing or coming industries,” according to Maha Haji, assistant professor in the Sibley School of Mechanical and Aerospace Engineering and senior author of the study.

In offshore aquaculture, fish are raised in farms in the open ocean instead of sheltered bays or onshore tanks. Offshore farms have the potential to provide a more sustainable source of food for the world’s population, but many are powered by diesel generators, which consume fossil fuels and release greenhouse gases into the atmosphere.

A wave-powered aquaculture farm (WPAF) mitigates these environmental problems by using wave-energy converters to capture the kinetic energy from ocean waves and transform it into electrical energy to power the farm.

In order to find a location for a WPAF, according to Haji, multiple variables must be assessed, including the physical ocean qualities for aquaculture, such as temperature, salinity and dissolved oxygen; the best wave energy location based on wave height and frequency; and the impact of other activities taking place in that ocean area, such as commercial fishing traffic, shipping lanes, military zones, marine-protected areas and, increasingly, offshore wind farms. 

Credit: SEA Lab

The researchers used publicly available geographic information system data and open-source software to evaluate more than 7,000 locations, narrowing the selection down to 52 feasible sites off the coast of Maine. 

They then identified an optimal site, located southwest of Acadia National Park. The site’s location as one of the farthest feasible sites from shore highlights what the authors found to be the cost-lowering benefit of siting a WPAF farther offshore, where the wave availability is greater than in closer, more sheltered areas. More access to wave resources means fewer wave-energy converters are required to produce the same amount of energy, lowering the cost. 

The use of readily available, open source data and software was chosen so that in the future communities can use this tool to make decisions for their own areas. For instance, fishers often keep the locations of their fishing grounds secret to protect them from competition, Haji said. This tool would allow users to input data relevant to their own situations, which they might not want to share publicly. 

“The goal of the study was to show that you can use marine spatial planning to understand all of these different data sets to drive decisions on where to place systems to reduce conflicts,” she said.

Haji’s group has previously done terrestrial planning, but this was their first foray into marine spatial planning. 

The paper’s first author, Gabriel Ewig ’24, was an undergraduate when the paper was written. Ewig, who began working in Haji’s lab as a sophomore, was responsible for collecting the geospatial data and running the models to assess the suitability of the sites. 

Ewig said he used information he learned from Haji’s class on multidisciplinary design optimization when working on this project. “In this case we were not really designing an object – we were designing a location,” he said. “So we were trying to optimize common factors to see if we could find a location that meets the sweet spot.”

Haji praised Ewig’s work. “He really was phenomenal – to be a first author on a journal paper as an undergrad just really speaks to how talented he is and how much he really led and contributed to the project,” she said.

Ewig, who graduated in May, currently works for an environmental nonprofit. He received funding from Cornell’s Engineering Learning Initiatives to work on the project. 

The paper’s other coauthors are Arezoo Hasankhani, assistant professor at the University of New Hampshire, and Eugene Won, senior research associate in animal science in Cornell’s College of Agriculture and Life Sciences.

The research was supported by the National Oceanic and Atmospheric Administration’s Sea Grant program.

Jane Bonassar is a freelance writer for Cornell Engineering.