Glow Sticks May Lure Sea Turtles to Death

Helen Scales
for National Geographic News
April 27, 2007

The same glow sticks that lighten up raves and Halloween may be tempting thousands of sea turtles to their deaths, a new study says.

Used to attract fish to hooks on miles-long lines, the lights are apparently also irresistible to the reptiles.

Commercial longline fishing operations are known to contribute to the decline of sea turtle populations.

Now researchers say that simply changing the type of light sticks could perhaps reduce the number of accidentally caught turtles.

The study is the first to demonstrate that sea turtles are attracted to the lights used by commercial longliners to lure swordfish and tuna. The paper appears in this month's issue of the journal Animal Conservation.

"Once the turtles are in the vicinity of the longlines, there's a high chance they will bite on the bait and become snagged," said study co-author John Wang of the University of Hawaii. "They can also get entangled in the fishing lines."

In 2000 alone, an estimated 200,000 loggerhead turtles and 50,000 leatherbacks were killed on longlines, according to the report. The World Conservation Union lists both species as endangered.

(Related: "Reopening Hawaii Fishery May Harm Sea Turtles, Experts Say" [April 1, 2004].)

Swimming Tests

To investigate whether visual stimuli attract sea turtles to longlines, Wang and colleagues used electronic tracking devices to monitor the movements of loggerhead turtles as they swam in a large laboratory tank.

"We put various commercial light sticks at the edge of the laboratory pool to see if the turtles would swim toward them," Wang said, "which they did."

The turtles swam toward yellow, blue, and green chemical glow sticks as well as orange LEDs.

Continued on Next Page >>




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