Using Geospatial Technologies to Map Illegal Fishing

Caitlin Dempsey


Worldwide overfishing is having a devastating effect on marine ecosystems.  A 2014 report from the United Nations Food and Agriculture Organization found that one-third of marine fish stocks worldwide have been overfished, and over 90% of the world’s fisheries are fully exploited or over-fished.  Give the vast expanse of the ocean (96.5% of the water on earth is found in the oceans, seas, and bays), tracking fishing boats and enforcing sustainable fishing practices is a daunting task.

Global Fishing Watch is an effort to use geospatial technologies to map and track illegal fishing.  A partnership between nonprofits Oceana and SkyTruth with Google was established to provide a web-based mapping application that allows the public access to commercial fishing activities occurring anywhere in the world:

Global Fishing Watch will be available to the public, enabling anyone with an internet connection to monitor when and where commercial fishing is happening around the globe. Citizens can use the tool to see for themselves whether their fisheries are being effectively managed. Seafood suppliers can keep tabs on the boats they buy fish from. Media and the public can act as watchdogs to improve the sustainable management of global fisheries. Fisherman can show that they are obeying the law and doing their part. Researchers will have access to a multi-year record of all trackable fishing activity.

The tools uses satellite tracking to monitor the activities of ships on the ocean and determine which ones are fishing based on the identity, speed and direction of broadcasting vessels:

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The tool uses a global feed of vessel locations extracted from Automatic Identification System (AIS) tracking data collected by satellite, revealing the movement of vessels over time. The system automatically classifies the observed patterns of movement as either “fishing” or “non-fishing” activity.

This version of the Global Fishing Watch started with 3.7 billion data points, more than a terabyte of data from two years of satellite collection, covering the movements of 111,374 vessels during 2012 and 2013. We ran a behavioral classification model that we developed across this data set to identify when and where fishing behavior occurred. The prototype visualization contains 300 million AIS data points covering over 25,000 unique vessels. For the initial fishing activity map, the data is limited to 35 million detections from 3,125 vessels that we were able to independently verify were fishing vessels. Global Fishing Watch then displays fishing effort in terms of the number of hours each vessel spent engaged in fishing behavior, and puts it all on a map that anyone with a web browser will be able to explore.

The tool is currently being used with Oceana to track problematic ships known for illegal fishing.  The tool will be released to the public in the near future.  The public tool will offer near real-time tracking of fishing activity.

Visit: Global Fishing Watch


Press Release: SkyTruth, Oceana & Google Announce New Technology Initiative to Illuminate Global Fishing Activity

Global Fishing Watch: Report from Oceana.


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About the author
Caitlin Dempsey
Caitlin Dempsey is the editor of Geography Realm and holds a master's degree in Geography from UCLA as well as a Master of Library and Information Science (MLIS) from SJSU.