Google Earth satellite images revealed Persian Gulf fisheries were using large fish traps for catches six times bigger than being reported.
In order to assess fishing practices in the Persian Gulf, researchers from the University of British Colombo used Google Earth images and were surprised at what they found. Persian Gulf fisheries were using large fish traps known as weirs; catching up to six times more fish than the numbers reported, according to a press release.
According to estimates by the researchers, there were around 1,900 fishing weirs along the coast of the Persian Gulf in the year 2005, and during this period the official number of fish taken in from seven countries was reported to be 5,260 metric tons. However, in actual fact the numbers if rightly calculated and based on the amount of weirs used would raise the fish take to more than 31,000 metric tons, which represents a difference of more than 25,000 metric tons.
"This ancient fishing technique has been around for thousands of years," said Dalal Al-Abdulrazzak, a PhD student with the UBC Fisheries Centre's Sea Around Us Project and the study's lead author. "But we haven't been able to truly grasp their impact on our marine resources until now, with the help of modern technology."
The fishing weirs used are semi-permanent traps that make full use of tidal differences to catch a wide variety of marine species. Used in Southeast Asia, Africa and parts of North America, some weirs can be more than 100 meters long. The findings of this study emphasize the need for using remote-sensing approaches, such as satellite imagery, to validate catch statistics and fisheries operations in general.
"Time and again we've seen that global fisheries catch data don't add up," says Daniel Pauly, principal investigator with the Sea Around Us Project and the study's co-author. "Because countries don't provide reliable information on their fisheries' catches, we need to expand our thinking and look at other sources of information and new technologies to tell us about what's happening in our oceans."
Findings of the study can be read here.
