Posted on by Steven Wilkie

Steven Wilkie: June 30, 2011

NOAA TEACHER AT SEA
STEVEN WILKIE
ONBOARD NOAA SHIP OREGON II
JUNE 23 — JULY 4, 2011

Mission: Summer Groundfish Survey
Geographic Location: Northern Gulf of Mexico
Date: June 30th, 2011

Ships Data

Latitude 28.32
Longitude -95.19
Speed 9.10 kts
Course 273.00
Wind Speed 12.71 kts
Wind Dir. 79.58 º
Surf. Water Temp. 28.20 ºC
Surf. Water Sal. 24.88 PSU
Air Temperature 29.50 ºC
Relative Humidity 75.00 %
Barometric Pres. 1014.84 mb
Water Depth 35.70 m

Science and Technology Log

So despite the long shifts, I managed to rouse myself out of bed early for my shift.  I wandered up to the drylab (just off of the deck) to check in and see what had been brought on board during the last trawl.  The second watch was working up a catch in the wet lab and on the deck was an unusual but significant catch, a sea turtle.  Definitely not a targeted species of

An unintended catch, the Kemp's Ridley (Lepidochelys kempi) was brought on board with one of the trawls, but returned to the sea safe and sound.

this cruise.   Although rare on NOAA cruises, sea turtles are unfortunately often caught up as bycatch by the fishing industry.  Bycatch is an unintended species in the net, and sea turtles were a  large bycatch component of the shrimp industry.

NOAA takes sea turtle bycatch very seriously.  No sooner had the turtle been put on the deck did the science team spring into action to collect vital statistics and data about the turtle before returning it back to the Gulf safe and sound.   The Kemp’s Ridley sea turtle (Lepidochelys kempi), like most sea turtles, is considered and endangered species.   By collecting data about the sea turtles, NOAA scientists can continue to monitor the health of the population, especially in light of last  year’s Deep Water Horizon oil spill.

Scientists worked the turtle up by collecting measurements (length and width) of the shell, and collecting a tissue sample in order to perform DNA analysis.  An electronic tag was inserted under the skin, so that if the turtle is caught again  it can be scanned and more data can be added to its file. This would allow scientists to determine migratory patterns and growth rates.  Finally the turtle’s rear flippers were fitted with tags that, again, would allow scientists to monitor its movement, age and growth.

Trained NOAA scientists measure the carapace length of our unexpected catch.Before being returned to the Gulf, the Kemp's Ridley is outfitted with two flipper tags. These tags can be used to help scientists monitor the life history of this particular turtle.
Trained NOAA scientists fit the Kemp's Ridley sea turtle with tags that can be used to collect additional data should the turtle be caught again.
In the early 1980s the situation with turtle populations in the Atlantic and Gulf of Mexico waters had gotten so dire, that scientists began researching ways to reduce turtle bycatch.  TEDs or Turtle Exclusion Devices were introduced to the shrimping industry on a volunteer basis.  These devices are rigged to the catch-end of shrimpers’ nets and act like a grate over a storm drain.  The water (and shrimp) can flow into the end of the net, but anything as big as a turtle is stopped and able to escape through a trap door.  To get a better idea of how a TED works follow this link to NOAA’s video of a TED in action.
  Today, TEDs are mandated on all trawl nets used by the fishing industry.  Although at first the shrimping industry was reluctant to embrace the technology, by working collaboratively, scientists, the fishing industry, and government legislators are helping to  curtail the drastic reduction in sea turtle populations in American waters.

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