Google Earth to monitor fish farming data. (Photo: Google Earth/Stock File/FIS)
Scientists use Google Earth to monitor fish farming data
Friday, February 10, 2012, 01:50 (GMT + 9)
Researchers at the University of British Columbia (UBC) have used Google Earth's satellite images to estimate the amount of fish being farmed in the Mediterranean Sea.
Published in the online journal PLoS ONE, this study is the first to approximate seafood production using satellite imagery. It focused on information from 2006.
“Our colleagues have repeatedly shown that accurate reporting of wild-caught fish has been a problem, and we wondered whether there might be similar issues for fish farming”, said lead author Pablo Trujillo, an Oceans Science Advisor for Greenpeace International, who conducted the study while a research assistant at the UBC Fisheries Centre.
Researchers chose to look at fish in the Mediterranean because it offered excellent satellite coverage and it was of personal interest, told Chiara Piroddi, co-author and an ecosystem modeler at the UBC Fisheries Centre.
They hand-counted 20,976 finfish cages and 248 tuna cages, the latter of which each measured more than 40 m across, she commented.
Almost half the cages were spotted off the coast of Greece and nearly one-third off Turkey.
Results tell that these and other countries appear to underreport their farmed fish production by up to 30 per cent, The Scientist reports.
“If the cages were running at maximum capacity we would be looking at around 50 per cent underreporting”, Trujillo specified.
For unknown reasons, the researchers pointed out, large portions of the coasts of France and Israel and some other areas did not have full satellite coverage and could not be examined.
Estimates made up of cage counts with available information on cage volume, fish density, harvest rates and seasonal capacity brought ocean finfish production for 16 Mediterranean countries at 225,736 tonnes (excluding tuna). The Food and Agriculture Organisation (FAO) had reported 199,542 tonnes for the region.
The estimate largely corresponded with government reports for the region, suggesting that most regional countries are giving accurate counts, the study concluded.
“The results are reassuring, and the methods are inspiring”, declared co-author Jennifer Jacquet, a post-doctoral researcher with UBC's Sea Around Us Project. “This shows the promise of Google Earth for collecting and verifying data, which means a few trained scientists can use a freely available program to fact-check governments and other large institutions.”
Trujillo agreed that Google Earth, thanks to its high-resolution images and consistent time series, represents a powerful tool for scientists and NGOs to monitor activities related to ocean zoning and fishing practices worldwide.
“These satellite images can help us identify those who are not acting responsibly”, he said. “To do this you don't have to ask for a million dollar grant, you just need enough time and a good set of eyes.”
By Natalia Real