Sunday, 2 March 2014

Have you ever met Ted?

Have you ever met Ted? No? Well, allow me.

TED Photo Credit: NOAA
In order to talk about Ted, we need to talk about shrimp fishing.
The shrimp fishery is a really big global industry. It's estimated that more than 3.4 million tons are caught per year, mainly in Asia. The way they fish shrimps is by using a fine meshed trawl net and this causes one of the main problems in the fishing industry: by-catch.
By-catch is when large amounts of other marine organisms are being caught while fishing for other species. Sea turtles are one of these species and when caught or entangled in a trawl net, they become trapped and unable to return to the surface. Since sea turtles are air-breathing creatures they eventually drown. And so? What can be done? Ladies and gentlemen: meet TED! TED (Turtle Excluder Device) is a  device that allows a captured sea turtle to escape when caught in a fisherman's net! Cool, uh? Super-cool!

But how did TED come about? And what has his fortune been?
Apparently, TED was first developed in the 70s by a fisherman named Sinkey
Mr. Sinkey Boone
Boone (quite on ominous name for someone traveling on a boat, I'd say) in Georgia. He named his invention The Georgia Jumper. Another type was patented on April 26, 1988 by inventor Noah J Saunders of Biloxi, Mississippi.

The main idea was that by decreasing the number of unwanted fish and creatures caught in their trawl nets, fishermen could trawl longer with the same net ideally catching more shrimp (and make more money!).
In 1987, all trawling boats in USA had to equip their nets with TEDs by law. Two years later, the USA implemented the shrimp-turtle law. This law stated that all countries from which the USA was importing shrimp had to certify that the shrimp they shipped were caught by boats equipped with TEDs. Countries that couldn't do this were banned from exporting shrimp to the USA. Go, Yankees!!!!
A few years later, in 1996, the Indian government proposed a similar legislation but with a modified "indigenous" TED, which they called TSDs (Turtle Saving Devices): basically it has fewer bars.

But... how does TED work?
Well, there is a metal grid integrated into the trawl net structure. The grid acts as a barrier for large creatures (such as sea turtles) from passing through the bars into the back of the net. A small opening in the net is then available either above or below the grid so that the creatures that are stopped by the TEDs are allowed to escape the net, relatively unharmed. TED seems to be very efficient: 97% of by catch escapes the net. However, sea grass and other debris reduce fishing effectiveness of TEDs.

So, is it all hunky dory?
Obviously not. Although TEDs have definitely reduced sea turtle casualties as by-catch, they still have a few failings and drawbacks:
  • Larger sea turtles, loggerheads and leatherbacks, are too large to fit through the escape hatches installed in most TEDs. U.S. legislation introduced in 2003 has attempted to address this issue by increasing the size of the escape chutes in the device
  • It is difficult to enforce TED compliance as TEDs can reduce the efficiency of the net system, resulting in a loss of some of the catch.
  • Occasionally TED use becomes impractical due to debris in the water. When a TED is clogged with debris, it can no longer catch fish effectively or exclude turtles.
What is the latest about TED?
Recently there was an improvement in the TED design: the TTED (Trash and Turtle Excluder Device). It can additionally free other forms of by catch, reduces sorting time and risks of injury due to sharks and rays being caught, improves the quality of shrimps, which are less likely to be crushed in the bottom of the trawl, and may also lead to a reduction in the amount of fuel consumed by the boats. The TTED is the culmination of years of research. The TTED was developed by the CRPMEMG and fishermen with the assistance of NOAA, IFREMER, the French Ministry of Agriculture and Fisheries, Région Guyane, the European Fund for Fisheries (FEP) and the WWF.

For more info, read the amazing section on TED in the NOAA website.

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