We hear a lot about the toll that large-scale fishing operations are taking on wild fish populations, but when you add them all together, small-scale fisheries can have quite an effect, too. A new fish-body-shape analysis system could help keep them in check.
Led by Steven Canty from the Smithsonian National Museum for Natural History, a team of scientists gathered yellowtail snappers from three fishing grounds located off the coast of Honduras. On each fish, the researchers made a total of 21 measurements between various anatomical features, then compared those measurements to the overall length of the animal.
What they found was that while snappers caught in any given fishing ground had the same body shape as one another, each ground produced fish with a shape that was subtly unique to that location. This was even the case with fish gathered from areas just 5 km (3 miles) apart from each other.
The scientists believe these location-specific body shapes are determined by local factors such as ocean depth, the strength of the current, and diet.
In its current form, the system is about 80 percent accurate at identifying where a fish was caught, based on its shape. Down the road, the researchers hope that it could be used to quickly and inexpensively check if fishermen have been overfishing certain regions, or have even been taking fish from protected areas.
"You take a pair of callipers, record measurements and give the fish back to the fisher," says Canty. "They can then sell it, and you can tell where that fish was caught from."
Also taking part in the research were scientists from Stanford University, Manchester Metropolitan University, the British Geological Survey, and conservation company Rare Inc. The findings are described in a paper that was recently published in the Journal of Applied Ecology.
Source: Smithsonian