Even though fishing activities have been monitored for selected fleets using electronic vessel monitoring systems, logbooks, and onboard observers, these efforts only provide very limited evidence of a region’s fishing patterns. A new study published by Science Magazine has made use of global satellite-based observations along with artificial intelligence to train and analyse the 22 billion messages publicly broadcast from marine vessels’ automatic identification system (AIS) from 2012 to 2016. The particularity of movements relating to fishing have led to the identification of more than 70,000 fishing vessels ranging from 6 to 146 m in length, with a 95% accuracy. The movements of these commercial fishing vessels have been tracked hourly and reveal a global ‘heat map’ that covers more than 55% of the ocean’s surface or over four times the area covered by agriculture.
Although the data set includes only a limited proportion of the world’s estimated 2.9 million motorized fishing vessels, it encompasses most of the larger vessels exceeding 24m in length and is estimated to account for between 50 to 70% of the total high seas fishing.
Over the course of 2016, the data set captured 40 million hours of fishing activity by these vessels covering a combined distance of more than 460 million km, the equivalent of traveling to the moon and back 600 times, and consuming 19 billion kWh of energy.
The heat map reveals an uneven distribution of fishing with global hot spots in the northeast Atlantic (Europe) and northwest Pacific (China, Japan, and Russia) and in smaller regions off South America and West Africa. Most nations fished predominantly within their own EEZ, with 5 states, (China, Spain, Taiwan, Japan, and South Korea) accounting for more than 85% of observed fishing effort on the high seas.
Surprisingly, where and when fishing occurred was tied more to politics and culture, like large drops in activities during weekends and holidays in the northern hemisphere, than to natural cycles such as variations in climate or fish migration. Ray Hilborn, a fisheries researcher at the University of Washington, told Seafoood Source that the study failed to provide any new insight, but had valuable information on how fishing patterns change throughout the year, and is helpful in combating illegal, unreported, and unregulated fishing and other rogue activities on the high seas. “The real positive of this, is to make the fishing industry realize that fishing is public. Everybody is going to know where you are, all the time”. Global Fishing Watch has all the data from the study available for download.