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NEWSLETTER ISSUE 2/09 March 2009

Diving at the shallow end: Green turtle behaviour in near-shore foraging habitat. (Abstract)

Hazel K, Lawler IR, Hamann M (2009)
First published in Journal of Experimental Marine Biology and Ecology 371: 84-92

Green turtles Chelonia mydas of immature and adult size (n=19, curved carapace length 49 to 118cm) were equipped with time-depth recorders for short periods (=7 d) to investigate diel and seasonal variation in diving behaviour. Research sessions were distributed over 2 years to cover seasonal variation in sea temperature from 14°C to 30°C.

Diurnal diver were shallower and shorter than nocturnal dives, with diel patterns also evident in dawn and dusk peaks in occupation of depths within 1m of the surface, elevated diurnal occupation of depths 1 to 2 m below the surface and elevated nocturnal occupation of depths >2m.

Dive duration increased as sea temperature decreased, showing strong negative correlation by day and by night. Study turtles made resting dives that were 3 to 4 times longer in median duration, and six times longer in maximum duration, at cool temperatures than they were at warm temperatures, but there was no evidence of winter diapaus or location shift to avoid cold water.

The large majority of turtles spent 89 to 100% of their time at depths =5 m below the surface, three individuals did not exceed 3m and the maximum depth recorded by any turtle was 7,9 m, although deeper water was available.

Furthermore, the dive data indicated that study turtles collectively spent more than 80% of their time at charted (low tide) depths of 3 m or less, indicating that they consistently used the shallow margins of the bay where human activities tend to be concentrated, therby potentially increasing their exposure to anthropogenic threats.

[The study was conducted in Moreton Bay, on the east coast of Australia using Star-Oddi DSTs.
The whole article can be viewed at]


Green turtle distribution. Red circles represent major nesting locations, yellow circles represent minor nesting locations.

New DST tilt



DST tilt is the newest member of Star-Oddi product line. It is a temperature, pressure (depth) and tilt logger with a 360° tilt range measured in three directions. The housing is centi size (15mm x 46mm).

DST tilt is an evolution of the DST pitch & roll. The new tag offers higher accuracy on relative tilt  measure-ments (+/-2°) and a better resolution(0.2°) since tilt is measured in three instead of two directions with a greater tilt range. 

The logger can be attached both internally and externally. DST tilt is suitable for e.g. analyzing fish movements and patterns over a long period of time as well as for studying marine mammals with a high range of vertical, horizontal and rotating movements. DST tilt can also be used as a stand-alone logger for analyzing fishing equipment and underwater gear. 

Up to 29,000 measurements per parameter can be recorded by the DST tilt. Tilt and temperature-pressure measurements can be uncoupled and recorded with different sampling intervals. The pressure sensor can be calibrated for up to 300 bar (3000m depth).


Star-Oddi Changes Logo in
April 2009

Star-Oddi changes logo and launches new website in April 2009. A lot of work has been put into polishing up Star-Oddi these past few months. Soon we can all enjoy the fruits of creative work done by us here at Star-Oddi and most importantly by our ad agency Pl├ínetan and DaCoda who are responsible for the webdesign. We wanted to give you all a peek preview on our new logo. Ta-daa!  

The new Star-Oddi logo

Star-Oddi Compass and Tilt Recorders

-DST pitch & roll measuring temperature, depth and pitch&roll movements of the DST in two directions, in reference to the earth gravity

-DST tilt (3-D) measuring temperature, depth and tilt in three directions. Better resolution! More accuracy!

-DST compass measuring temperature, depth and compass heading with reference to the magnetic north in two directions.

-DST comp-tilt (3-D) measuring temperature, depth, tilt in three directions and compass heading with reference to the magnetic north. Better Resolution! More accuracy!

Visit Our Website

Visit our website and view other products and scientific papers related to your field. If you would like to receive a price quote, know more about the company or the products please contact us.

Did you know that...?

60% of the world's Atlantic Puffins breed in Iceland. The Atlantic Puffins (Fratercula arctica) live most of their lives at sea, resting on the waves when not swimming.

They are excellent swimmers that use their wings to swim like they were flying underwater. Puffins can dive to depths of over 60 meters (200 feet), though they usually stay underwater for only 20 to 30 seconds at a time.

Even though the Atlantic Puffin doesn't look like it's made for flying it can reach speeds of 88 km/h (55mph) by flapping its wings up to 400 times per minute.

Puffins are said to be faithful to their spouse for their whole life, up to 20 years. They return to the same breeding grounds every year to parent a single chick both nursing the offspring.

Atlantic Puffin feeds mostly on Capelin and Sandlance. The last few years there has not been enough of these small fish for the Puffins to feed on in Icelandic waters and that has led to a noticeable decrease in the Puffin population.

Star-Oddi's DST milli-TD tags have been used in tagging Atlantic Puffins in Iceland. Read more about it here.


Star-Oddi | Vatnagardar 14 | 104 Reykjavik | Iceland | Tel: +354 533 6060 | Fax: +354 533 6069 |

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