Fish Farms at Sea: The Ground Truth from Google Earth

Gargana Fish farms near Manfredonia, Italy. Photo source: ©© Verity Cridland

Abstract, PLos One

In the face of global overfishing of wild-caught seafood, ocean fish farming has augmented the supply of fresh fish to western markets and become one of the fastest growing global industries.

Accurate reporting of quantities of wild-caught fish has been problematic and we questioned whether similar discrepancies in data exist in statistics for farmed fish production.

In the Mediterranean Sea, ocean fish farming is prevalent and stationary cages can be seen off the coasts of 16 countries using satellite imagery available through Google Earth. Using this tool, we demonstrate here that a few trained scientists now have the capacity to ground truth farmed fish production data reported by the Mediterranean countries.

With Google Earth, we could examine 91% of the Mediterranean coast and count 248 tuna cages (circular cages >40 m diameter) and 20,976 other fish cages within 10 km offshore, the majority of which were off Greece (49%) and Turkey (31%). Combining satellite imagery with assumptions about cage volume, fish density, harvest rates, and seasonal capacity, we make a conservative approximation of ocean-farmed finfish production for 16 Mediterranean countries. Our overall estimate of 225,736 t of farmed finfish (not including tuna) in the Mediterranean Sea in 2006 is only slightly more than the United Nations Food and Agriculture Organization reports.

The results demonstrate the reliability of recent FAO farmed fish production statistics for the Mediterranean as well as the promise of Google Earth to collect and ground truth data…

Read Full Study, PLos One

Photo source: ©© Jeremy Weate

Google Images: Satellites Spy on Fish Farms, The Scientist
In a study published on February 8th in PLoS ONE, researchers using Google Earth to count and measure the number of coastal fish farms in 16 countries on the Mediterranean Sea, found that while the overall fish production in the Mediterranean was close to what the United Nations Food and Agriculture Organization (FAO) reported for the region, several countries underreported their aquaculture production by up to 30 percent…

Overfishing costs EU 3.2bn euros each year, BBC
Overfishing of EU fisheries is costing £2.7bn (3.2bn euros) a year and 100,000 jobs, a report has said. “Overfishing is the single most destructive force in the marine environment” said report author Rupert Crilly, environmental economics researcher for the foundation’s Ocean 2012 initiative.

Impacts of Intensive Fish Farming