Satellite Tracking Update: ‘Bonni’

25 January, 2019

After four months, ‘Bonni’s’ satellite transmitter stopped working… This could, for example, be the result of a mechanical issue with the transmitter, because the device fell off ‘Bonni’s’ carapace, or because she drowned as a result of fisheries or was poached.

Although it is a shame that we can no longer follow ‘Bonni’s’ movements, we are extremely happy with everything we’ve learnt about green turtle migration behaviour in the past months! ‘Bonni’s’ active behaviour during her nesting intervals, swimming back and forth between Bonaire, Las Aves and Los Roques, is something we had not seen before.

Normally, female turtles nest once every two or three years, because the migration from the foraging home to the nesting site (often hundreds of miles) and the nesting itself is exhausting work. However, since ‘Bonni’s’ foraging home is located very close to Bonaire, which means that the nesting migration only takes her about two days, we are hoping that she’ll return to Bonaire again this year for another successful nesting season!

8 January, 2019

‘Bonni’ started the new year in the Los Roques Archipelago. She continues to forage in the most western part of the island group. On the map you can see where ‘Bonni’ has been for the past 10 days.

15 November, 2018

A quick update on ‘Bonni’s’ whereabouts!

‘Bonni’ is really enjoying the Los Roques Archipelago. As you can see on the map, ‘Bonni’ has lately been spending most of her time in the western part of this beautiful Archipelago.

‘Bonni’ first arrived in Los Roques on October 15, then quickly returned to Bonaire to attempt to lay another nest, and – when that proved unsuccessful – swam back to Los Roques where she’s now been since October 27.

We’ll continue to monitor her movements and will update you again in December!

30 October, 2018

On the evening of October 23rd, ‘Bonni’ came ashore once more! She attempted to lay her sixth nest of this season, but – unfortunately – did not succeed. Right after she started digging, ‘Bonni’ hit a large rock, which prevented her from digging any further. She then decided to turn around, to go back to the ocean.

When sea turtles attempt to lay a nest, but for some reason are unsuccessful, they may try again either the same or the next night. We were therefore hoping that ‘Bonni’ would return to the beach again to try once more. ‘Bonni’, however, had her own plan: after the attempt, she went back to the sea and started swimming towards the east again. She did not come back ashore to lay a nest…

The last signal from ‘Bonni’s’ transmitter shows that she’s back in the Los Roques Archipelago.

We’ll continue to monitor her movements and will update you if anything changes!

23 October, 2018

Guess who’s back! ‘Bonni’ continues to surprise us… she has once again returned to Bonaire!

Friday evening, at 10:34pm, ‘Bonni’ started her journey from Los Roques to Bonaire. She covered approximately 86 nautical miles/159 kilometers in 56 hours, and arrived on Bonaire in the morning of October 22. The yellow lines on the map show where ‘Bonni’ sped; the blue lines, on the other hand, indicate where ‘Bonni’ swam a little slower.

Although we have fitted 26 adult sea turtles with satellite transmitters over the past 15 years, we have not seen migration behavior like ‘Bonni’s’ before. This shows us that we can learn valuable lessons about foraging and breeding habits from each individual sea turtle fitted with a transmitter.

We believe ‘Bonni’ may have returned to Bonaire because she felt the urge to lay another nest. We now have to wait patiently to see what her plans are. To be continued!

16 October, 2018

Yet another surprise! ‘Bonni’ did not stay in Las Aves, as we suspected, she instead decided to continue her journey eastward to the Los Roques Archipelago – an area rich with coral reefs and seagrass.

‘Bonni’ is not the first turtle tracked by STCB to travel to the Los Roques National Park. In 2006, STCB deployed a transmitter on a female hawksbill named ‘Heit’. ‘Heit’, who had already been tagged on Bonaire in 2004, traveled to her foraging waters at Los Roques after completing her nesting season on Bonaire.

Los Roques, a National Park since 1972, is located just to the east of Las Aves. In 2006, after it became clear that ‘Heit’ lived in Los Roques, STCB’s Manager Mabel and Field Specialist Funchi went to the archipelago to see if they could spot ‘Heit’. And… Funchi did see a glimpse of her! In 2008, a diver spotted ‘Heit’ again on Bonaire (see photos above).

We look forward to find out whether ‘Bonni’ will stay in Los Roques, just like ‘Heit’…

9 October, 2018

After laying her fifth nest, ‘Bonni’ left Bonaire and started to swim eastward. As we did not receive a signal for approximately 36 hours, we weren’t sure whether she had returned to the Las Aves Archipelago or had gone elsewhere. Luckily, we received a signal again on the evening of October 3rd: ‘Bonni’ had arrived at Las Aves!

For the past five days, ‘Bonni’ has been going back and forth between Isla Aves de Sotavento and Isla Aves de Barlovento. The Archipelago consists of a grand total of twenty-one islets and islands, it therefore seems to be a perfect place for our adventurous traveler ‘Bonni’!

3 October, 2018

‘Bonni’ continues to amaze us! On Monday night, ‘Bonni’ came ashore again to lay her fifth nest of this season… And by now, her first nest is already close to hatching!

After laying her nest, ‘Bonni’ began her journey eastwards, possibly towards Las Aves again. The last signal we received from her transmitter was yesterday morning at 8:22am and we’re now waiting to see where her journey will take her this time.

We will update you when we receive a new signal!

28 September, 2018

‘Bonni’ has once again returned to Bonaire and we believe she may be laying another nest in the coming days!

The migration behavior of previously tracked sea turtles on Bonaire has been different from ‘Bonni’s’ journey. ‘Bonni’ has been toing and froing between Bonaire and the Las Aves Archipelago, returning to Bonaire multiple times to nest. Since we have not seen a migration pattern like this before, we contacted sea turtle expert and former STCB manager Robert van Dam to better understand ‘Bonni’s’ actions.

According to Robert, a possible explanation for ‘Bonni’s’ migration behavior is that, after laying a nest, ‘Bonni’ may feel ’empty’: she thinks that she has finished her nesting season and therefore starts her journey back home. However, after a few days she once again feels the urge to nest.

In this case, sea turtles can show different behaviors or strategies. When a turtle feels the urge to nest, but is not at her nesting site, she can either make her way to a nearby nesting site to lay a nest, or – if she does not find a suitable nesting place – she can abandon her eggs in the sea. Another strategy, one that ‘Bonni’ seems to be using, is to leave her foraging home to return to her nesting site once more.

We’ll find out soon whether ‘Bonni’ will be laying another nest, and we’ll keep you posted!

Thank you Robert for sharing your knowledge with us!

25 September, 2018

‘Bonni’ is turning out to be a perfect match for Corendon: she’s a true traveller!

After laying her fourth nest on September 21st, ‘Bonni’ once again returned to Las Aves (she swam 31.7 nautical miles in less than 24 hours!) and spent three days at Isla Aves de Sotavento. This morning, however, she was on the move to Bonaire AGAIN! At 9:43am, she was just 16 nautical miles east of Bonaire…

We’re anxiously waiting to see whether she’ll visit our island again to surprise us with yet another nest!

21 September, 2018

We are excited to share with you that ‘Bonni’ came ashore last night and laid her fourth nest of this season!

After returning to the sea, ‘Bonni’ started swimming east again, possibly towards the Las Aves Archipelago. We are curious to see whether ‘Bonni’ is indeed going back to Las Aves; or will her journey take her elsewhere? And, if she is making her way to Las Aves again, will she actually stay this time or will she return to Bonaire once more to surprise us with another nest?

We hope to find out soon!

18 September, 2018

This morning, signals showed that ‘Bonni’ has definitely returned to Bonaire! We’re very eager to find out whether she’ll lay another nest…

September 17, 2018

Yesterday morning at 11:00am, ‘Bonni’ was still in the Las Aves Archipelago. However, when we checked the map this morning, we found out that ‘Bonni’ is swimming towards Bonaire again! What a surprise!

STCB has satellite tracked twenty-six sea turtles so far and ‘Bonni’ is the first tracked post-breeding sea turtle that ‘has done a loop’ like this after leaving Bonaire. This information supports STCB’s ongoing satellite tracking program, as there is not a ‘one fits all’ formula. Each tracking experience enhances our knowledge about migration patterns and thus gives us a better understanding of how to best protect sea turtles within the Caribbean region.

‘Bonni’s’ migration behavior does pose several questions. For example, is it common for green turtles to travel this far during their inter-nesting periods? And, will ‘Bonni’ return to Bonaire to lay one or more nests or is she merely passing by to continue north? Or is it possible that ‘Bonni’ lives on Bonaire, even though Bonaire’s habitat is a developmental habitat and not a feeding ground for adult turtles?

To be continued…

September 14, 2018
Signals from the satellite transmitter show that ‘Bonni’ is currently cruising along the eastern part of the Las Aves Archipelago. It is known that female sea turtles don’t eat, or eat scarcely, while migrating from their feeding grounds to their nesting beach and commonly not at all once the laying has started. This in order to save space for the eggs to develop in their bodies. Hence, the turtles lose the fat reserves that they built prior to their reproductive migration. For this reason, if suitable habitat is found in their migration back home, sea turtles may stop to eat and regain some energy for their journey. It may be that ‘Bonni’ is doing that right now in Las Aves, where mangroves and seagrass beds are part of the marine ecosystem providing a good feeding site for green turtles. It is also possible that ‘Bonni’ lives in the Las Aves Archipelago; we can’t wait to find out during the coming days!

September 13, 2018
On Monday, September 11, a satellite transmitter was deployed on a green turtle named ‘Bonni’, right after she finished laying her nest. With this technology we can track ‘Bonni’ in real-time during her migration to her feeding habitat. This information guides best management practices for the conservation of sea turtles in the region. For more information, please visit our website.

The satellite transmitter was fitted at 4:00am by STCB staff and volunteers. We started to receive signals immediately and we could see that ‘Bonni’ left Bonaire right after returning to the sea, which indicates that this may have been her last nest of this season and she started her journey back home under a beautiful night full of stars.

‘Bonni’ is now 43 nautical miles from Bonaire, on the most eastern part of the Las Aves Archipelago. Las  Aves is located north of Venezuela, between Bonaire and the Los Roques Archipelago. The last signal was received at 10:29am this morning and we’re eager to find out where she’ll go next!

Thank you Corendon for funding ‘Bonni’s’ satellite transmitter! For more information about the Corendon Foundation (in Dutch), please visit their website.

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