Partnering with Planet to bring coastal waters and small vessels into focus

High-resolution optical imagery expands views and leads to significant advances in vessel detections

We set out on an audacious goal at Global Fishing Watch two years ago: to map all human activity at sea. We are making incredible strides toward this goal thanks to our partnership with Planet, which enables us to draw on timely, high-resolution satellite imagery.

We have already used satellite imagery to map human activity at scale, processing more than two petabytes of imagery from the European Space Agency’s Sentinel-1 and Sentinel-2 satellites. However, while their imagery has allowed impressive breakthroughs, it only allows us to see larger vessels. The vast majority of fishing vessels–more than two million–are under 12 meters in length, fish predominantly close to shore and do not broadcast their GPS coordinates. Those vessels dominate the world’s coastal waters, but are too small to be detected in the free imagery we have processed from the Sentinel constellations.

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Aerial view of colorful fishing boats docked side by side at a harbor, floating on calm, dark water. Neatly arranged in rows along the pier, these vessels reflect the vital role of fisheries and highlight maritime CO2 emissions concerns.
The majority of fishing vessels are under 12 meters in length and operate in areas close to shore.

But that is changing. We are bringing small vessels into view by drawing on huge amounts of higher resolution imagery from Planet, processing two million square kilometers of imagery from their satellites per day. And while we are still refining the technology and vessel detections, we are already seeing incredible results. These results will inform better enforcement of marine protected areas, produce detailed global maps of trawling activity, enable new maps of global aquaculture and even help us estimate the carbon footprint of humanity at sea.

Here’s how.

Studying global coastal waters

Planet is an industry-leader in capturing ocean data, with over 20 million square kilometers of ocean imagery collected daily – including nearly all coastal waters at 3-meter resolution. This is essential to monitoring smaller vessels that spend almost all of their time close to shore. In fact, we estimate that vessels under 12 meters spend almost all of their fishing effort in the first 20 kilometers from shore, an area that accounts for less than 5 percent of the ocean.

Sentinel-2 data has allowed us to see where vessels have been active, so we have used its lower 10-meter resolution imagery to decide where to “zoom in” and then obtain higher resolution images from Planet. The area we have selected looks like a halo around the continents, extending far from shore only in shallow areas that see heavy fishing along the continental shelves.

A full color physical global map showing coastal regions, with areas Global Fishing Watch uses Planet imagery for vessel detections highlighted in bright yellow.
Planet’s imagery covers nearly all coastal waters globally at high resolution. Areas that we are focusing on for vessel detections are shown in yellow. © 2025 Global Fishing Watch

Producing detailed maps of vessel activity

By combining detections over time, we can make maps that show the average activity of vessels throughout a region. We can also detect the size of vessels in imagery, their orientation and each vessel’s speed, based on its wake pattern.

Abstract digital art depicts jagged, red-lit cliffs against a dark blue background, evoking the dramatic landscapes near the Patagonian toothfish fishery. Twisting shapes and textured surfaces form an open center, creating a sense of depth and space.
This map visualization shows vessel detections in a region of Southeast Asia over a period of six months. Detections are color-coded based on size, with larger objects being yellow and smaller objects being red. © 2025 Global Fishing Watch

Detecting smaller vessels

Our research suggests we can detect vessels as small as 5 meters in length, or even less if the boats are moving. This is a huge advance from what is possible with Sentinel-2 imagery, as can be seen in this image from Planet of a two day lobster season in the Florida Keys. Moving boats are clearly visible with their wakes, but each of the small white dots are also vessels. All of those boats–more than 40 in this image–are too small to detect through our other imagery sources. Relying solely on using Sentinel-2 imagery, we would have undercounted the number of vessels by about a factor of 10.

A satellite image shows three bright streaks, likely missiles, crossing over dark green land and clouds—an unusual scene often far from concerns like maritime CO2 emissions or the Patagonian toothfish fishery—leaving glowing trails behind at night.
Vessels taking part in a two-day lobster season in the Florida Keys. © 2025 Planet

Mapping detailed impacts of human activity

We can also detect specific types of fishing using Planet’s imagery. One of the most destructive and controversial forms of fishing is bottom trawling, which drags a net along the seabed, damaging benthic ecosystems and resulting in very high rates of bycatch. Trawlers often kick up lots of sediment in their wake as they fish – large plumes we can map from space that can disrupt marine biodiversity and contribute to the climate crisis.

Composite image shows aerial views of dark, swirling trails in blue water near a coastline, likely created by multiple boats or ships—potentially highlighting the impact of maritime CO2 emissions in active fishing areas.
From top left, clockwise: satellite images show bottom trawlers operating near the coast of Texas, western South Korea and the Guangdong Province of China. © 2025 Planet

Fishing may be the most widespread activity in the ocean, but it is not the only one. In addition to seeing where trawlers disturb the seabed, we can see where sand dredgers are impacting marine ecosystems. These dredgers may be clearing channels for vessel traffic, or harvesting sand for construction. Sand mining is itself highly destructive and better maps of where this activity takes place could guide better management.

A satellite view of three sediment clouds surrounding active vessels operating offshore in deep blue water.
A satellite image shows plumes of sediment in the water surrounding active sand dredgers operating near the coast of Bahrain. © 2025 Planet

Another activity that is growing rapidly in the ocean is aquaculture. Mariculture–aquaculture in the ocean–now accounts for about 20 percent of the fish from the sea consumed by humans and is growing. It is widespread, with cages or pens clearly visible in Planet’s imagery in coastal regions including Norway, Vietnam and Chile.

Three satellite images show a variety of aquaculture operations–both cages and pens–visible in the ocean just off coastal regions.
From left, clockwise: satellite images show mariculture facilities in Xuan Dai Bay, Vietnam, Boknafjord, Norway, and the Gulf of Ancud, Chile. © 2025 Planet

Revealing encounters

It is common for vessels to meet up at sea to exchange goods and crew. However, this can also be a way to try to avoid oversight at ports and these encounters are often associated with illegal transfers of goods or crew. Using Planet’s imagery, we can now detect vessel encounters at scale across the global coastal waters.

A grid of aerial images showing various cargo ships at sea, each ship viewed from above with different colors and lighting, highlights their role in maritime CO2 emissions amid dark or blue water backgrounds.
A variety of thumbnail images from Planet’s imagery that show vessel encounters at sea. © 2025 Planet

Estimating the carbon emissions of all vessels at sea

Finally, one of our goals at Global Fishing Watch has been to estimate the greenhouse gas emissions of all human activities in the ocean. However, our current estimate misses most of the vessels smaller than 12 meters. Although their emissions are small compared to the cargo and tanker vessels, they are still important, potentially accounting for maybe a third of emissions from the fisheries sector. Because we can estimate the speed of each vessel and its size using Planet’s imagery, we can also estimate the amount of fuel being used, and thus the estimated carbon emissions.

World map of 2023 maritime carbon dioxide emissions with bright yellow lines on major vessel routes and color scale from 1 to 10 tons/km²
In this map of estimated emissions from maritime traffic in 2023, greater emission concentrations can be seen in the shipping lanes of the world, with the highest levels in East and Southeast Asia. Understanding the activity of smaller vessels will allow us to improve these estimates. © 2025 Global Fishing Watch

A new era in ocean monitoring

Historically, what happened on the ocean went unmonitored and undocumented, which is a major reason that as much as 20 percent of fishing activity has been illegal, unregulated or unreported. Unlike on land, where you can use public mapping services to see satellite imagery of almost every building in the world, in the ocean there are no public maps of where fishing activity, shipping, mining, aquaculture and offshore energy activities are taking place. Now, with Planet’s high resolution imagery, we are revealing these activities throughout the world’s coastal waters. This information can empower better enforcement, improved placement of marine protected areas, and a fairer, more equitable use of the oceans. 

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