Latest Updates on the STRETCH Project
Send Questions to loggerheadstretch@gmail.com
4/24/2024
George Balazs (STRETCHCo-PI) completed his trip to Japan and the Port of Nagoya Public Aquarium. While there he conferred with the aquarium staff and observed the juvenile loggerhead turtles of STRETCH cohorts 1 and 2. Below is a video of cohort 2 being feed at the aquarium.
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| George and Masanori meeting with the two veterinarians caring for the juvenile loggerheads of cohorts 2 and 3. |
Above: PNPA Turtle Specialist Tomo Feeding Stretch Turtles in Tank 2
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| Splash10 297 satellite tag that will be placed on three juvenile loggerheads from cohort 2 in late june, 2024. |
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| Masanori Mori (PNPA Chelonia Curator & STRETCH Team Member) holds a Splash10 297 depth/ temperature tag (Splash10 297, Wildlife Computers) on one of the three larger turtles that will carry this special tag on the second release. These tags will give us more information about their diving behavior and temperature preferences during their time in the central north eastern Pacific. |
4/2/2024
Co-Pi Balazs traveling to Nagoya to check on cohort #2!
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| George Balazs ready to board the shinkansen from Osaka to Nagoya. |
Co-PI George Balazs will travel to Nagoya Japan on 4/11/2024 to check in with the Port of Nagoya Public Aquarium about our second and third cohorts of loggerhead turtles. He will work with the head turtle curator (Masanori Mori) who is raising our juvenile loggerheads to inspect each member of the two cohorts to ensure they are healthy and, in the case of cohort 2, that they will be ready to have satellite tags attached in late June / early July, 2024. He will also work on a materials list and logistics for the next tag attachment and subsequent release with PNPA Director Masanori Kurita.
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| Looking down on the Port of Nagoya Public Aquarium. The Chelonia institute is the flat roofed structure on the left in front of the cylindrical towers. |
Loggerhead turtles being raised at PNPA.
4/1/2024
Satsuki and Kumeyaay continue to transmit locations and are currently about 1000 km northeast of the Hawaii Islands archipelago.
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| Satsuki's track from 7/11/2023 to today (4/1/2024). Water temperature at satsuki's location is 15 degrees C. |
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| Kumeyaay's track from 7/11/2023 to today (4/1/2024). Water temperature at kumeyaay's location is 18-19 degrees C. |
STRETCH project is presented at the 42nd annual ISTS in Thailand.
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| Larry Crowder presents an update on the STRETCH project at the 42nd International Sea Turtle Symposium in Thailand. |
3/28/2024 -
Summary of Tracking Data From 7/11/23 TO 3/28/24
Below is a table that lists the name, days transmitting, total distance traveled and calculated speed of travel for the 25 juvenile loggerheads release in July of 2023. It may be difficult to read all the numbers and I am happy to share a copy of the document if needed. The averages are interesting however: Taking Hauoli and Ayame out of the mix because they ceased transmission early on, the average length of transmission was 241 days or ~8 months (stdev = 14.9), the average distance traveled was 6434 km (stdev = 801) and the average speed of travel was 1.11 km/h (stdev= 0.11).
3/22/2024
In looking ahead towards the situation in the eastern Pacific ocean as we move toward summer and the second deployment, it appears that our el nino pattern is going to be very short lived and we will be moving into a strong la nina situation this summer. This will be fortuitous for our experimental project since the first cohort of turtles experienced warmer la nina waters in the eastern Pacific ocean possibly facilitating the movement of our 7 juvenile loggerheads into the "thermal corridor" and on towards Baja California.
As we move into the summer months, la nina should pick up strength and waters in the eastern north Pacific will be cooler possibly creating a thermal barrier to the movement of these juvenile loggerheads over to Baja California... Thats the theory!
Below is a video (NOAA coral reef watch) of the last 90 days Dec 23, 2023 to March 22, 2024) of sea surface temperatures showing the well formed tropical band of warm water off of the west coast of South America and the change in temperature as the easterly winds pick up and draw deeper cool water to the surface off the coast of Peru and moves it west across the central / tropical Pacific.
3/19/2024
Below is a wildlife computers map of the 3 juvenile loggerhead turtles that are still transmitting locations. The reason for the others going off line is almost certainly the drop in battery voltage... the power remaining is insufficient to send any messages to the Argos satellites. We are already preparing for the second cohort of turtles. Co-PI George Balazs will be visiting the Port of Nagoya Public Aquarium in April to see how well our second cohort of turtles is doing. All reports from the chief curator at the Chelonia Institute, Masanori Mori, indicates that all of the 2nd Cohort of turtles are doing well and growing at a very acceptable rate. Our goal is to deploy the 2nd cohort of juvenile loggerheads in the same location and at around the same time as the first cohort. We are awaiting confirmation from the shipping company about their sailing times in June and July.
Note: in addition to our 25 Spot 387 location only tags, the team has decided to deploy 3 additional tags (Splash10-297) with dive and temperature sensor capability to get a better idea about what the turtles are doing while they are moving along their trajectories.
3/15/2024
Below is a video of the two tracks taken by Victor and Tsubaki since they were released on 7/11/23 (248 days ago). Tsubaki is currently in the bay of Vizcaino where it appears to be foraging in relatively shallow waters (<50m deep) sometimes only a couple of kilometers from the shoreline and Victor is off of the coast of Baja California (125 km) in waters that are approximately (2000 m deep).
The trajectories of Tsubaki and Victor over the last 248 days (7/11/23 to 3/14/24) since their release.
3/12/2024
Ten of our juvenile loggerheads continue to transmit locations as of 3/12/24. They have been sending us locations for 248 days now which is amazing. See map of the tenacious 10.
All of the remaining tags are getting low on battery power (see below):
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Above are the 10 juvenile loggerheads that are still transmitting locations. According to Wildlife Computers, once the voltage drops below 3.0 transmissions will become very unlikely. It seems that some of our little loggerheads are getting by on less voltage and still transmitting, |
Bottom line is that we are nearing the end of our transmissions from our loggerheads. They will continue for a while more but note that they have produced amazing tracks and have given the STRETCH team a huge amount of data to work with. It has been and still is a very successful first year. We look forward to the second cohort of turtles currently being raised at the Port of Nagoya Public Aquarium by Masanori Mori to be satellite tagged and released in late June or early July of 2024.
3/5/2024
Nadesiko, Victor and Tsubaki continue to transmit their locations near the west coast of North America/Baja California. It appears that they have been lingering in some areas where they have found forage. Interestingly, Nadesiko and Victor have moved out into deeper waters in the last two days. Tsubaki is moving north and south along the coastal region of Baja California.
3/1/2024
Below is a look at the trajectories of our three loggerheads that have reached the coast of North Ameriaca/Baja California. Their tracks are very interesting and seem to be indicative of turtles feeding along relatively shallow waters where they may be able to forage on the bottom as well as on the surface and in the water column.
2/28/2023
Over the last 10 days we have noted that there are a number of turtles that are no longer sending locations. The reason they have stopped transmitting is most likely due to low battery voltage. Once the voltage moves below 3.0 volts, there is no longer enough power to transmit information to the ARGOS satellites. Thirteen of the original 25 are still transmitting and we have hopes that they will have enough power to continue for a while.
NOTE: These satellite tags, for various reasons, have variable life durations for the batteries. We have done some investigation of this and you can look at some of the conclusions in this paper by Parker, et al.
The seven turtles that have entered the thermal corridor (Kai Malino, Chuy, Sazanka, Pua Sakura, Nadesiko, Victor and Tsubaki) are still transmitting. Nadesiko is, surprisingly, only 1.5 km off of Santa Catalina Island as of 2/26/24. That is an amazing track and was rather unexpected. The water temperature around Catalina is about 15 degrees C which is getting a bit low for the comfort of loggerheads. I am thinking she might start heading south soon..?? Victor is about 20 km offshore on the continental shelf (water is ~225 m deep) and Tsubaki is about 5 km off of Punta Racosa in about 80 m deep water.
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| Twelve of our 25 turtles have stopped transmitting as of 2/28/24. Above are some statistics relating to those turtles and their satellite start and end date, tag voltages, and total days transmitting. |
The Magnificent 7
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| Above are the current locations of the 7 loggerheads( Kai Malino, Chuy, Sazanka, Pua Sakura, Nadesiko, Victor and Tsubaki) that have entered what we identify as the thermal corridor. |
2/19/2024
Twenty of our 25 juvenile loggerheads continure to transmit locations and they are scattered over an large area of the central north Pacific Occean (~4900 km separates Chumash and Tsubaki). It appears that there are two strategies being employed by our 2023 cohort of turtles. Thirteen of them have remained at the same longitude or have moved west of their release point. Four of them have moved east of their release point but remain well out in deep water 300 to over 1000 km from Baja California. That means that 17 of the 22 remain in the pelatic environment (77%). Three turtles are very near the shore (Nadesiko is approximately 40 km west of Encinitas, California, Victor is about 40 km south west of Ensenada, Mexico and Tsubaki is ~ 3 km off of Baja California coastline) and represent the second strategy of moving into shallower waters where they might become more benthic (bottom) feeders (%). All 22 of the loggerheads are in water between 15 and 18 degrees C. To learn a little more about why we think there are two major survival/migratory strategies used by north Pacific juvenile loggerheads, please take a look at this paper by Peckham et al. 2011. A publication regarding arial surveys of the waters off of Baja California in 2014 will give you some idea of loggerhead abundance in those waters... see Seminoff et al.
Note that Nadesiko has moved up to an area just off of the coast of California. From an earlier post: Cali Turner (STRETCH team member) just reported that "colleagues at SWFSC (Southwest Fisheries Science Center, NOAA) who were conducting sea lion scat monitoring at the Channel Islands just reported that red crabs are in the area and being consumed by those predators. Another sign of what loggerheads nearing the coast may find to eat!" This insight might help explain the northerly course that Nadesiko has taken lately (she is approximately 70 km southeast of San Clamente Island-part of the Channel Islands... food!
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| Each yellow ICON represents the location of each of the 22 juvenile loggerheads still transmitting as of 2/19/2024. They are all located in waters that are between 15 and 18 degrees celcius that corresponds to the band of water between 29 and 34 degrees latitude (they were released at ~42 degrees latitude). |
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| Nadesiko's track since her release on July 9, 2023. She is now off the coast of Southern California. |
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| A closer look at Nadesiko's and Victor's locations as of 2/19/24. Nadesiko is between the California Coast and the Channel Island of San Clamente. It is unusual to see loggerheads in that area. |
2/16/2024
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| Victor, Nandiseko and Tsubaki continue their interest in the coastal areas of Baja California. Tsubaki was last shown to be in water ~60 meters in depth while Nandiseko and Victor are still in the pelagic environment where the water is >1000 m deep. |
CaliCali Turner (STRETCH team member) just reported that "colleagues at SWFSC who were conducting sea lion scat monitoring at the Channel Islands just reported that red crabs are in the area and being consumed by those predators. Another sign of what loggerheads nearing the coast may find to eat!" This insight might help explain the northerly course that Nadesiko has taken lately (she is approximately 70 km southeast of San Clamente Island-part of the Channel Islands... food!
2/14/2024
Of the 22 juvenile loggerheads still transmitting locations, 7 of them (31.8%) have entered the region that has been identified as a possible thermal corridor. It is hypothesized that during period when the water is warmer in this area (during El Nino years) as it is now, juvenile loggerheads are able to pass across this area and potentially reach the coastal regions of Baja California. During a La Nina year, this corridor would be closed to them because of cooler waters.
We have chosen to measure the extent of the movements of the turtles entering this thermal corridor with the establishment of 4 "Waypoints" that help to identify the progression to what might be considered the complete migration to benthic forage grounds in the coastal areas of Baja California.
The Four Waypoints are:
- Have they entered the thermal corridor as defined in Briscoe et al.? 7 turtles have (Victor, Nadesiko, Tsubaki, Sazanka, Pua-Sakura, Ka La Ula & Chuy)
- Have they left international waters and are 200 nm or less from the coast? 3 turtles have (Victor, Nadesiko & Tsubaki)
- Have they crossed onto the continental shelf? 1 turtle has (Tsubaki)
- After arriving to the neritic habitat, is their movement pattern and site fidelity consistent with behavior in long-term foraging site?
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| The above image shows the paths of all 25 juvenile loggerhead turtles and outlines the region designated as a potential thermal corridor (yellow rectangle) showing that 7 of the loggheads have entered into the Thermal Corridor. |
2/12/2024
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| Three our our 25 juvenile loggerhead turtles are making their way towards Baja California. Tusbaki has reached the continental shelf and is waters that are less than 100 meters deep. |
Nadesiko, Victor and Tsubaki continue their travels towards Baja California. While Nadesiko and Victor are still roughly 100 km from reaching the continental shelf off of Baja California, Tsubaki is currently in waters about 70 meters deep and only 11 km from the shoreline of Baja California. Tsubaki is moving south southeast in waters that are about 16 degrees C and in a current that is moving about .8 km/h at 150 degrees (south-southeast). CoPI Jeff seminoff said "... Tsubaki’s current trajectory would take her to Baja's northern-most Pacific coast, an area that is not known as a loggerhead hotspot. It’s possible that Tsubaki would stay in that northern neritic area, but my hunch is that it’ll probably ride the southbound California Current surface waters, south past Vizcaino Bay and Cedros Island and into the Gulf of Ulloa, where it will stay for a while."
2/8/2024
They are closing in on Baja California
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| Victor, Nadesiko and Tsubaki are getting closer and closer to Baja California. |
Our three turtles (Victor, Nadesiko and Tsubaki) continue on their south, southeasterly course and Tsubaki is getting near the narrow Baja California continental shelf. CoPI Dana Briscoe has produced some nice animations to show how the travels of our juvenile loggerheads correlate with the 18 degree C isotherm and Chlorophyll a concentrations. It is very clear that the movements of the loggerheads "follows" the 18 degree isotherm. They move north during the summer as the warmer water moves north and, as cooling occurs and the warmer water moves south, the turtles follow along. The Chlorophyll a concentrations (indicative of higher biological productivity-more food) do not clearly indicate a direct correlation, but further analysis may clarify the relationship. It is clear that Victor, Nadesiko and Tsubaki are headed toward higher Chlorophyll a areas along the Baja California coastline.
Please see the animations relating to sea surface temperature and chlorophyll a concentration below:
Sea Surface Temperature and trajectories of 25 juvenile loggerheads (animation by Dana Briscoe).
Sea Surface Temperatures and the trajectories of 7 juvenile loggerheads that are nearing Baja California (animation by Dana Briscoe).
Animation of the 7 juvenile loggerhead that are approaching Baja California in relation to the Chlorophyll a concentration (animation by Dana Briscoe).
2/1/2024
Twenty two of our juvenile loggerheads continue to transmit accurate locations as of February 1, 2024. They have been actively transmitting for 207 days. Seven of them are still moving in a southeasterly or easterly direction and three of them (Victor, Nadesiko and Tsubaki) are getting quite close to the continental shelf off of Baja California. I have uploaded a chart of the 7 loggerheads to show their approximate location relative to Baja California and below that are the individual tracks of the 7 with the approximate distance from North America/ Baja California.
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| Combined map of the 7 juvenile loggerheads that are still moving in the direction of Baja California. |
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| A closer look at Victor, Nadesiko and Tsubaki has them within 400 or 500 km of the coast and they are nearing the continental shelf of North/Central America. |
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| Chuy's location as of 2/1/24- ~1100 km from southern California. |
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| Ka La Ula's location as of 2/1/24- ~1212 km from southern California. |
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| Nadesiko's location as of 2/1/24- ~415 km from Baja California. |
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| Pua-Sakur's location as of 2/1/24- ~478 km from southern California. |
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| Sazanka's location as of 2/1/24- ~911 km from Baja California. |
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| Tsubaki's location as of 2/1/24- ~275 km from Baja California. Tsubaki is nearking the continental shelf. |
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| Victor's location as of 2/1/24- ~419 km from Baja California. |
1/22/2024
Below is a screen shot showing the locations of the 23 juvenile loggerhead turtles as of 1/22/2024. You will note that they are all pretty much in the temperature zone of ~17 degrees C.
Below is a timpe lapse of sea surface temperature over a 90 day period from 10/24/23 to 1/21/24 showing the southerly movement of lower SST temperatures over time.
Dr. Dana Briscoe (STRETCH Co-PI) has developed a marvelous map that allows us to look at individual tracks and see lots of additonal information. Dana wrote, "This provides similar functionality to the Wildlife Computers map, with the ability to toggle tracks and layers on and off. Please find the legend as a pull-down menu in the top right-hand corner.
If you turn off (‘un-check' the box) for All Tracks, you can select & view individual tracks along with their specific dates, latitudes and longitudes (something we had wanted out of the Wildlife Computers map), by clicking along the track.
Layers for the California Current Large Marine Ecosystem (CCLME-The California Current marine ecosystem is a highly productive coastal ecosystem in the northeastern Pacific Ocean. Seasonal upwelling of cold, nutrient-rich water fuels populations of krill, squid, sardines, and other species that are fed upon by larger fishes, seabirds, and marine mammals) and Thermal Corridor study region are also included in the map options.
Click here to see this very informative graphic.
01/18/2024
Below is an updated image that shows the "box" that is thought (hypothesized) to encompass the region where juvenile loggerheads experience conditions that might be favorable for them to make the transition all the way to Baja California. The box is an area between 25 and 35 degrees north latitude and 115 and 135 west longitude. As you can see, 5 of the loggerheads (Ka La Ula, Sazanka, Nadesiko, Tsubaki and Victor) are within the boundaries of the "box" and two of them (Chuy and Pua Sakura) are very near the northern boundary of the box.
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| Locations of 7 loggerheads that have come near or entered the area where conditions may be fovorable for them to migrate further south and east towards Baja California. |
01/07/2024
Below is an image that shows the "box" that is thought (hypothesized) to encompass the region where juvenile loggerheads experience conditions that might be favorable for them to make the transition all the way to Baja California. The box is an area between 25 and 35 degrees north latitude and 115 and 135 west longitude. As you can see, 6 of the seven loggerheads mentioned below are just entering the "box" and the seventh is quite near it.
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| Of the seven loggerheads discussed below, 6 have entered the "box" that is hypothesized as an area where conditions cound be favorable for transition to the coastal area of Baja California. |
01/03/2024
HAPPY NEW YEAR EVERYONE!
As the new year begins all 23 of our juvenile loggerheads continue to transmit and show their locations. They are all still moving in a southerly direction and 7 of them (Tsubaki, Victor, Pua Sakura, Nadesiko, Ka La 'Ula, Sazanka & Chuy) are moving in a southeasterly direction. These 7 little loggerheads seem to be the best candidates for moving eventually all the way to Baja California. Below is an image of the map of the movements of these seven turtles for the last 4 months. You can also check on the map here to see updated tracks over the coming weeks.
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| The map above outlines the tracks of the 7 juvenile loggerheads that may possibly be BAJA BOUND and Tsubaki seems to be well in the lead at this point. |
12/25/2023
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| After 170 days 23 STRETCH Project juvenile loggerheads continue to transmit locations and they are generally moving in a southerly direction. One big questions is why are they spread out so much in an east- west direction ... what is driving them. |
ANIMATION
Below is the latest animation of the trajectories of 23 juvenile STRETCH turtles still transmitting. Many have traveled more that 4000 km during the last 170 days since their release on 7/11/2023. Below is an unlabeled video of the trajectories of the 23 turtles.
12/18/2023- STRETCH Co-PI Dana Briscoe has produced an animation of the STRETCH loggerheads' weekly average locations and sea surface temperatures.
2/13/2023
Co-PI George Balazs returned to Hawaii yesterday after traveling to Japan to attend the 34th annual Sea Turtle Association of Japan Symposium at the Port of Nagoya Public Aquarium (PNPA) in Nagoya, Japan. While he was there he met with aquarium director Masanori Kurita, Masanori Mori (Chief, The Chelonian Research Institute Division, PNPA) , Tomomi Saito (Director, Usa Marine Biological Institute, Kochi University) and Noah Yamaguchi (Graduate Student. Kochi University, Kochi, Japan) (all four are STRETCH team members).
The principle subject of the team meeting in Nagoya was the health and status of the second cohort of juvenile loggerhead turtles being raised for release some time in early July of 2024. The cohort looked to be in very good condition and Mori-san said that they were all feeding well and growing at a normal rate.
The third cohort of turtles from Kochi is also at PNPA and are destined for release in July of 2025.
Below are some pictures taken during George's visit.
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| Masanori Mori, George Balazs and Noah Yamaguchi at the STAJ symposium. Mori-san and Noah-san were the two team representatives that traveled with the turtles to their release point on July 11, 2023. |
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| George and Tomomi Saito at STAJ symposium. |
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| Juvenile loggerheads (cohort 2024) in their tank at the PNPA. |
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| Masanori Mori holds one of the juvenile loggerheads of cohort 2024. |
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| Masanori Mori with a juvenile loggerhead from cohort 2024.... nice and healthy looking!!! |
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| A juvenile loggerhead, member of cohort 2025. |
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| Four juvenile loggerheads from cohort 2025. |
12/11/23
Our 23 Juvenile loggerheads continue to transmit locations and are staying in waters that are between 15 and 18 degrees Celsius.
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| The tracks of the 23 juvenile loggerheads are shown above. The location on the left is an anomalous location and can be ignored. All of the loggerheads are remaining in waters that are between 15 and 18 degrees celsius. |
12/6/23
LATEST STRETCH NEWSCAST- ABC 7 News
Members of the STRETCH team (Dana Briscoe and Larry Crowder) explain the thermal corridor hypothesis and how we are testing it in a news cast on ABC News Channel 7.
11/27/2023
It has been 7 days since out last update on the locations of our 23 satellite tagged loggerheads. As of this morning, all 23 are continuing to move in a southerly direction (some southeast, some southwest) staying ahead of the cooling waters.
Relative to the chart below, STRETCH Co-PI Jeff Polovina wrote, "It is interesting that our current release turtles are in slightly cooler waters than the NOAA product band indicating the zone with highest probability of interaction between loggerheads and longliners. There are likely 2 reasons for this. First, as loggerheads get larger they occupy slightly warmer waters and the NOAA product focuses on larger turtles that are more likely to get caught by longliners. See Fig 3 in the attached paper for the SST vs size relationship. Secondly the NOAA product takes into account historical interactions that are based on the distribution of fishing effort. So in summary our current releases are behaving as expected, at least in terms of SST and latitude."
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| The figure above shows the locations of the 23 loggerheads (blue dots) relative to the red area where NOAA feels the where most pelagic loggerheads congregate. See NOAA website ("Turtle Watch") |
11/20/2023
All 23 of our tagged loggerheads continue to transmit accurate locations. I have created a map below that shows their tracks overlayed with the current sea surface temperature.
11/15/2023
Stretch team member Alberto Abreu presented an updated overview of the STRETCH project to a welcoming 25th meeting of the Grupo Tortuguero de las Californias at the Gran Acuario Mazatlán on 15th November. The participants were keenly interested in getting to know what motivated the study and the details of how the project was carried out. A particular interest was to know how the adopted "Mexican" turtles were doing and when we would expect them to reach the Americas, if at all. Most of the people who were honored by having their names adopted for 5 of the tagged turtles were there and expressed profound feelings. Don Victor stood up at the end to manifest his and Mariel's appreciation and happiness that they were able to see the results of scientific studies to which they have generously contributed. Go here to see more about the presentation.
11/13/2023
All 23 of our tagged loggerheads continue to transmit accurate locations. I have created a map below that shows only their current location in case you are interested.
11/6/2023
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| The Nov. 6 locations of 23 juvenile loggerheads are shown above as black dots... each dot has an associated lat-lon. All 23 are north of the edge of the TZCF (see below). |
Jeff Polovina (Stretch Co-PI) has commented on the importance of the Transition Zone Chlorophyll Front (TZCF). "The TZCF is the boundary between the very light green oligotrophic waters (chl < 0.1mgC.m3) and the darker green cooler, more temperate and higher chl waters (ch>0.3mgc/m3). Victor is pretty much at that boundary just slightly north. To the east you see the much higher chl values due to the coastal upwelling and some nice chl filaments. " The map above shows the relative cholorphyll values and the edge of the TZCF - light green chlorophyll values are .07 mg/cubic meter and the darker green values are 0.2 mg/cubic meter. You also notice the dark green area that Jeff refers to above as resulting from coastal upwelling with chlorophyll values from 0.7 t0 1.7 mg/cubic meter (areas with very high productivity).
Chlorophyll concentrations are a proxy for biological productivity... higher values, higher productivity... more food available for our little turtles.
The turtle named Victor is the farthest east and is approximately 550 km from the coast of California.
11/2/2023
Recent tracking of 6 loggerheads and video of presentation about STRETCH by Team member Bianca Santos.
Above is an animation of the 6 loggerheads that continue to move to the southeast (Chuy, Ka La Ula, Nadesiko, Pua Sakura, Tsubaki and Victor). They have traveled an average of ~ 3000 km since their release on July 11, 2023.
Go to the web site to see all of the tracks.
STRETCH Team member Bianca Silva Santos presented an overview of the STRETCH project at the Pices conference in Seattle, WA. Please see her presentation below.
10/26/2023
Co-PI Dana Briscoe has created another wonderful animation of the movements of the juvenile loggerheads relative to the 18 degree C isotherm.
10/23/2023
All 23 juvenile loggerheads continue to transmit locations and they are continuing to move to the south. The six loggerheads that had been moving in a south-easterly direction continue moving to lower latitudes and 4 of the 7 (Victor, Ka La Ula, Tsubaki and Chuy) have turned a little to the west in the last few days. All 23 remain in waters where the temperature is between 16 and 19 degrees C. Below are a few images showing the 7 loggerheads that have been moving to the southeast. Victor, the closest to mainland North America remains approximately 900 km west of California.
10/17/2023
Six loggerheads continue to move south easterly (Tsubaki, Chuy, Ka La Ula, Victor, Nadesiko, and Pua Sakura). It looked like Bety was also trending easterly but has recently been moving pretty directly to the south. The other 16 juvenile loggerheads are also moving to the south or south west remaining within waters that are 10-19 degrees centigrade. Below is a comparison of all 25 tracks (left) and the six turtles that are moving south easterly (Bety is included here also) indicated by the circle. There is also an animation of the 7 loggerheads trajectories up to 10/17/23 in the video below.
Seven loggerheads are trending easterly in their movements (Bety, Tsubaki, Chuy, Ka La Ula, Victor, Nadesiko, and Pua Sakura). In theory, they may continue to move southeasterly as long as the sea surface temperature remails warm enough. If they do, they may reach the SCB (shown above) and be able to move on down towards Baja. We hope to be able to follow their movements over the next few months to see if they continue to move southeast.
10/11/2023
Where are they headed? Jeff Seminoff (Stretch Co-PI) feels that they may be headed to the Southern California Bight. The SCB is a productive area and home to a diversity of whale, dolphin, fish, and lower-trophic prey
species. It is also the only area off California where loggerheads periodically occur en masse. These turtle
aggregations in the SCB can number in the 10s of 1000s of individuals, and most frequently occur during warm El
Niño periods when local waters are their warmest.
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| Southern California Bight |
See Jeff's full explanation here.
10/9/2023
As of Monday, 10/9/23, 6 of our loggerheads are trending southeast and are in waters that are around 17 degrees centigrade. If you look at the map of all 23 currently transmitting turtles, you will note that virtually all of them have "headed south" as cooler waters decend from the north Pacific ocean.
The six turtles making this easterly move are Ka La Ula, Victor, Tsubaki, Nadesiko, Pua Sakura and Chuy.
Below are the tracks of the 6 southeasterly trending
loggerheads. They are in 16 to 19 degree C water.
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10/6/2023
There are 6 of our loggerheads that have begun to move to the south-east and I share their combined paths in the video below.
10/4/2023
Twenty Three of our loggerheads continue to transmit locations with 20 of them remaining largely within the same areas as they were on September 14th. This probably indicates that they are finding forage in those areas and are not needing to travel longer distances in search of food. Three of the loggerheads (Ka La Ula, Tsubaki and Victor) have moved a significant distance to the southwest and this is interesting and exciting for us to see because it is possible they are responding to some stimuli (food, temperature, currents, etc.) that help to validate the premise of this deployment- the Thermal Corridor Hypothesis.
Here are three URLs that will allow you to take a look at each of the three turtles relative to sea surface temperature and surface currents.
Below is a short video of the three loggerheads tracks from July 11 to September 3, 2023. All three of them moved northwards rather rapidly and, as they got into cooler waters, they began to slow down (the "whirling" of the turtles indicates slower movement) and, we believe, forage on more abundant food. As the surface temperatures cooled and the 17 degree isotherm began to move south, they also moved south remaining in waters with a surface temperature between 16 and 18 degrees C.
Our STRETCH turtles are wandering around in the same general area having apparently found waters where they are able to find food. I have assembled the tracks of the group and made a little movie of their movements from 8/19/23 to 9/14/23. When you see them spinning around it means they have remained in an area and gone "back and forth" before moving along.
Above: Animation by Dana Briscoe showing the movement of the loggerhead northward from their point of release until they reach the 17 degree Isotherm and how they are looping back to follow that isotherm.
Above :Animation of tracks of the juvenile loggerheads as they move around an area where we think they are able to find food.
9/8/2023
Twenty-four of our 25 juvenile loggerheads continue to transmit after nearly 2 months. They have slowed their northward movement as they reached 17-18 degree C waters where they have most likely encountered a more abundant food supply. As can be seen in the example track of "Akamai" below, the little loggerheads have begun to meander more, apparently after having found a good feeding area. While we can't know for sure what they are up to, previous work has indicated they are in an area where warm and cold currents converge which concentrates food items.
This video displays Akamai's travels since it was released on 7/11/2023 until 9/8/2023. It has moved steadily north until it reached waters that were 17-19 degrees C where is has lingered because it probably found a favorable food supply.
8/30/2023
Stretch Team PI, Dana Briscoe, has put together a short animation of the 25 satellite tagged loggerheads to show how they are moving north in relation to the 17 degree C isotherm.
8/15/2023
A note from Jeffery Polovina (Oceanographer and Stretch Co-PI)
"I'm intrigued by Kai Malino's behavior between about Aug 4-12. It remains in a pretty small area and may represent foraging activity. Most of the tracks are showing fairly directed transiting behavior moving northward to preferred temperature habitat. Occasionally however we see the turtles slow down to spend time in a small area as Kai Malino did between Aug 4-12. Loggerhead turtles often feed on floating animals including velella velella (by-the-wind sailors), pelagic snails, and gooseneck barnacle attached to floating debris. Kai Malino's departure from its northward transit during the period Aug 4-12 may mean that it came across an aggregation of food."
For more information on the diet of oceanic loggerheads see - oceanic diet
Below is an enlarged track of Kai Malino during the times mentioned by Jeff above.
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| The image on the right is the enlarged section of the image shown on the left. This section spans the time mentioned by Jeff above (8/4 to 8/12/2023). |
Possible food items that might be consumed by juvenile loggerheads
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| Pelagic snail (Janthina sp.). |
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| By-the-wind sailor, Velella velella, a colonial siphonophore. |
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| Gooseneck barnacles living on a float that has washed up on the beach but can be found out in the open ocean where our littel turtles can get at them. |
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| The photo above is of one of our juvenile loggerheads released on 7/11/23 from a ship into the north central pacific. Note the Wildlife Computer tag on its back. It is on the ship's deck while its carrier is cleaned and fresh sea water added. 8/15/2023 This is an update on the tracks of our juvenile loggerhead turtles as of 8/15/23. Twenty four of the twenty five turtles are still transmitting and continue to move northward. Ayame (PTT id no. 243198) has not transmitted since 8/10/23. While we do not know why Ayame has stopped transmitting, previous work (Parker, Balazs, Rice and Tomkeiwicz (2014) Variability in reception duration of dual satellite tags on sea turtles tracked in the Pacific Ocean. Micronesica.) indicates that there could be a multitude of factors that impact signal transmission. The first thing that comes to mind, of course, is that the animal died and sank, but it could also be that there was damage to the tag antenna from an impact, overgrowth by marine algae and invertebrates attached to the tag, tag loss (for some reason it came lose and was lost), tag malfunction because of internal electronics and any combinations of the above. We have had similar situations during our more than 200 previous deployments where a tag stops transmitting. The good news is that we still have 24 loggerheads transmitting strongly. Hopefully, Ayame is ok and still out there doing what turtles do. 8/11/2023 Hau'oli continues to move to the north while the rest of the juvenile loggerheads continue moving to higher latitudes.  |
8/3/2023
Hau'oli changes direction
Checking in on today's tracks we find that the one loggerhead (Hau'oli) that has been behaving differently that the other 24 loggerheads (it has been moving to the south instead of to the north) has turned to the north and is moving along against a small current (.33 kts to the southeast). We, of course, don't know what will happen tomorrow but, for now, Hau'oli is moving to the north-northwest. Before turning to the northwest, Hau'oli was traveling at about 1 km/hr. Turning to the west seems to have slowed progress to about .6 km/h ( that speed plus the opposing current would add up to about 1 km/h).
7/31/2023
Below are two animations of the tracks of our 25 juvenile loggerheads overlain on maps showing the 17 degree C isotherm and the transition zone chlorophyll front (TZCF). In both cases, past tracking has shown that loggerheads favor being near both (17-18 degree C and the TZCF) so they are moving north in that direction. Animations created by Dana Briscoe.
17 degree isotherm and loggerhead tracks.
TZCF and loggerhead tracks.
7/28/2023
As of July 28, 18 days at sea, 24/25 turtles are heading north toward the North Pacific Transition Zone. The northern most turtles are in 18-19C0 water which indicates they are entering this feature where their food is most concentrated (posted by L.Crowder).
For more information on the North Pacific Transition Zone click here.
7/25/2023
Latest Wildlife Computer Map
What are they foraging on out there? It could be any number of things from pelagic crustaceans, jellyfish, salps, larval fish-almost anything they can catch. Loggerhead turtles are opportunistic feeders, and their diet can vary depending on the availability of prey items in different areas and at different times of the year.
Below is a list of all 25 juvenile loggerheads showing the approximate distances they have traveled since their release on 7/11/2023 until their current positions on 7/25/23. Their average rate of travel (km/h) is calculated based on their travel distance and the time since release (~336 hours). (these are all rough estimates)
7/23/2023
As of 7/23/2023, all 25 juvenile loggerheads continue to move northward(map below). The reason for this northward migration is likely the result of cooler waters providing conditions where more food is available. Jeffrey Polovina (one of the project CIs) wrote, " ...this movement, based on our past work, is that the loggerhead turtles have a preferred habitat defined as between 17 and 20 C SST that also typically coincides with an ocean front termed the Transition Zone Chlorophyll Front that likely provides forage. During the summer months this temperature habitat and front shift northward as the ocean warms so the turtles move northward to remain within this habitat. Then of course in the fall the ocean cools and the preferred habitat moves south along with the turtles. Seasonally the little guys move north and south about 1,000 km all while moving east or west."
7/19/2023
Please go to loggerheadstretch.org for more detailed information on the individual paths and the project in general.
As of 7/19/2023, all 25 juvenile loggerheads continue to move northward(map below). The reason for this northward migration is unknown but may be related to water temperature (cooler waters to the north) and the availability of food.
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7/16/2023 |
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| All 25 of the satellite tagged juvenile loggerheads are moving northwards. See the map where you can click on individual turtles and view their names and tracks. |
7/13/2023
Below is the map of the locations and movements of the 25 juvenile loggerheads. Tracks can be seen on the official website.
More images from Masanori and Noah
Our turtle whisperers, Noah and Masanori, have shared a few more photos of their days at sea with their 25 juvenile loggerheads. Please enjoy.
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| One of the juvenile loggerhead turtles with a spot 6-387 Wildlife Computers tag attached. |
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| Masanori Mori (Port of Nagoya Public Aquarium) holding one of the juvenile loggerheads. |
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| Noah Yamaguchi (Kochi University) holding one of the satellite tagged juvenile loggerheads. |
7/12/2023
Below is a map showing the locations and movements of the 25 juvenile loggerhead turtles released from the ship Galaxy Ace on 7/10/2023. So far they have not moved very far as they are undoubtedly acclimating to their new surroundings.
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| Each of the 25 turtles has a name and can be viewed separately as soon as the web site become publicly available (should be available on 7/13). |
7/10/2023
Today was release day for our 25 turtles that have been traveling across the Pacific onboard a cargo ship. They were released by Masanori Mori and Noah Yamaguchi (Port of Nagoya Public Aquarium and Kochi University) who have taken care of the 25 juvenile loggerheads since they were satellite tagged on 19-21 June, 2023. Everyday on board the ship the two would feed the turtles, clean the containers they were living in and keep careful notes of the health of the turtles. The ship moved to 146 degrees west longitude where the water was warm enough to release the turtles, and they were safely released by Masanori and Noah and the ship's crew on July 10, 2023.
LOCATION OF THE RELEASE
Latitude and longitude of the released point
39°18.9N
146°04.0W
seawater temperature is 24.8℃
39°18.9N
146°04.0W
seawater temperature is 24.8℃
All 25 of the satellite tagged turtles are now giving positions, and their locations and tracks can be seen HERE when the website goes active on 7/13/2023.
Pictures sent by Masanori and Noah of the release and the happy crew are shown below
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| The ship's crew gets ready to lower the turtles in a basket by rope from the mid-deck of the ship to get them closer to the water's surface. (photo credit Masanori Mori) |
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| Each turtle was carefully lowered in its basket and then, when the turtle was very near the waters surface, the basket was "tipped up" and the turtle fell out into the North Pacific Ocean to begin its new life. (photo credit Masanori Mori) |
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| Lowering the turtle in the basket down to the waters surface. (photo credit Masanori Mori) |
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| The little loggerhead is free and swimming in the North Pacific ocean. (photo credit Masanori Mori) |
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| Another loggerhead just went "splash"! (photo credit Masanori Mori) |
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| The proud and happy Masanori Mori displays a STRETCH t shirt after all 25 loggerhead turtles were successfully released into the ocean. (photo credit Noah Yamaguchi) |
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| An equally proud, Noah Yamagushi!!! (photo credit Masanori Mori) |
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| And the very supportive and helpful crew pose for a group picture after the release. |
7/5/2023
Reports from our two colleagues escorting the turtles on the ship indicate that the turtles are in good condition and receiving good care. They are feeding and remain active and alert which is a good indication that they are handling the rigors of travel well.
7/3/2023
Our ship of opportunity has left Yokohama Japan and is proceeding on its way across the north Pacific.
It should reach the area where the satellite tagged loggerheads will be released between the 9th and the 11th of July. We wish our intrepid turtle caregivers (Masanori and Noah) good luck in the release of out 25 little turtles.
6/27/2023
The turtles have been safely loaded onto the transport ship and Masanori Mori and Noah Yamaguchi are taking good care of them on the ship until they are released sometime between the 9th and the 11th of July.
We wish them safe sailing and good health (turtles included)!
Below are pictures provided by several people showing the ship and the loading operation.
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| The crew and our "Turtle Guys" - Masanori Mori and Noah Yamaguchi. |
6/22/2023
We had a nice going away dinner at Aloha Cafe last night, and it was fun to relax a little and enjoy each others company. Some members of the team traveled to PNPA this morning to check in on the turtles and they happily reported that all is good.
Larry and Bianca will remain for the next 5 or 6 days to keep an eye on the turtles and then accompany them to the transport ship that will dock in Nagoya on the 27th. Hopefully they will share some photos of the loading.
6/21/2023
We were able to complete the attachment of the rest of the satellite tags for cohort 1 of the STRETCH research project. We finished work around 1230 hours and had a traditional toast to wish the turtles well on the next phase of their life in the central north pacific once they are released.
A juvenile loggerhead is named Lali (Larry) in honor of STRETCH director Larry Crowder.
A toast is given to the former Director of the Port of Nagoya Public Aquarium Itaro Uchida, current director Masanori Kurita, the wonderful people of Japan and the juvenile loggerheads that are beginning their adventure in the central north Pacific Ocean.
6/20/2023
Up at 0600 and headed out to breakfast. We are going to try and get an earlier start at the aquarium as we have 9 turtles to do today.
Below is the video of the attachment of 9 more satellite tags.
Day two of Satellite Tagging video. (higher resolution)
6/19/2023
We are off this morning to our first day of attachment work at the Port of Nagoya Public Aquarium.
AND... we completed the attachment of 7 satellite tags to the juvenile loggerheads turtles raised at the Port of Nagoya Public Aquarium. Below is a short video of the activities of the day. Tomorrow we will continue the work with the attachment of 9 more satellite tags.
6/18/2023
Most of the Stretch team that is going to perform the satellite attachment has arrived in Nagoya. Larry Crowder, George Balazs, Laura Jim, Marc Rice and 2 HPA students are in Kanayama and ready to go!
The students, working with her students, Rice and Balazs organized and programmed the tags for attachment tomorrow. We will do 7 tags tomorrow and 9 on each of the next two days.
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| From left to right, George Balazs, Laura Jim, Haruno and Rico work on organizing and cataloging the Spot 6-387 satellite tags. |
The team assembled at 1900 h and made their way to an introductory dinner at one of our favorite sushi restaurants. Larry Crowder and Dan Briscoe met our two HPA student volunteers and discussed the project and life over some great Japanese sushi dishes.
6/16/2023
Conditions at the "drop zone" continue to look good relative to sea surface temperature as the team prepares to fly to Nagoya to attach the satellite tags to the juvenile loggerhead turtles. We should have more to report in the next few days.
So, stay tuned!
6/13/2023
There are only three days left until our departure for Nagoya Japan. The team will assemble in Kanayama, Nagoya and begin work at the Port of Nagoya Public Aquarium on 6/19/23. The procedure will be to select a number of loggerhead turtles, place each of them in a separate "container," rinse them with fresh water, lightly sand their carapace (like filing your fingernails) to ensure the polyester resin will stick and prepare each one for the attachment. See the "attaching the tags" video for information on how this will be accomplished.
Once the tags have been securely attached and the resin is thoroughly dry, the tags will be painted with antifouling pain so that algal and invertebrate attachment to the tag will be minimized (too much growth will limit uplink data to the ARGOS satellite system).
Once everything is dry, the little loggerheads will be placed in salt water until they are ready for trans-shipment to the North Pacific ocean at approximately 145 degrees W longitude and 17 degree C water temperature where they will be released to fend for themselves (see SST).
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| The white circle indicates the approximately location where the satellite tagged juvenile loggerhead turtles will be released. |
6/9/2023
The First Satellite Tag Deployment
The first attachment and deployment of satellite tags on the first cohort of juvenile loggerhead turtles will take place in the latter part of June and early July. The team (Larry Crowder, Dana Briscoe, Bianca Santos, George Balazs, Laura Jim and Marc Rice + 2 HPA students (Haruno and Rico) will travel to Nagoya, Japan and the Port of Nagoya Public Aquarium (PNPA) on June 16th. They will begin attaching the satellite tags on 6/19 and complete attaching the 25 tags on 6/21or 6/22 (see video below). Once the tags are attached, the turtles will be placed in individual "baskets" in sea water and, at that time, the tags will automatically activate. We will have programmed the tags to send no messages (ARGOS uplinks) for the first 12 day to save battery life since the turtles will not be released until about 14 days after attachment.
Stay tuned for more updates as we do our work at PNPA.
6/2/2023
Cali Turner (Stretch Project Contributing Scientist) reported that a juvenile loggerhead turtle has been spotted off the Southern California coast recently in waters that are 17 degrees C. We don't know if it came up from the south (Baja population of loggerheads) or is a pelagic juvenile that may have traveled from the western north Pacific area. The development of an el Nino pattern is progressing, and warmer waters are moving northwards a little faster that is normal in neutral or la Nina years (see SST).
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| The red marker indicates where the juvenile loggerhead was sighted (images below). |
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| Loggerhead turtles sighted off of Southern California (34, -117). Photo provided by Cali Turner. |
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| Closeup of turtle shown above. Photo provided by Cali Turner. |
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| Sea Surface Temperature (SST) and the location of the loggerhead turtle observed (above). (https://www.ospo.noaa.gov/data/sst/contour/californ.cf.gif) |
5/31/2023
Below is a video about how we attached Spot 5 satellite tags to juvenile loggerhead turtles in 2009. The SPOT 6 tags are shaped differently but the basic procedure for attaching the tags is the same. This will give you a good idea of the process we will carry out on the 25 juvenile loggerheads that are being raised at the Port of Nagoya Public Aquarium.
5/19/2023
Tonight, George Balazs and Marc Rice activated 24 Spot six tags to test that they are communicating with the ARGOS satellites appropriately. All 24 of them communicated with the satellites very quickly, and we got positions that were generally appropriate and accurate. It is interesting that several of the tags' initial reading was many hundreds of km off but the second recorded position was generally in the right vacinity. It did take a little time for the satellites to figure out where the tags were actually located - usually less than one hour.
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| This Wildlife Computer map shows the locations of 24 Spot 6 tags activated and placed out in the open to initialize them and test for communications with the Argos satellites. This test occurred on 5/19/23 from 1730 hours to 1900 hours. |
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| Satellite tags arrayed on the lawn and cement wall. Tags were turned on at 15-30 second intervals to avoid overlapping signals. |
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| Single spot 6 tag with identification tag. |
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| Spot 6 tags lined up on the wall in the start mode. |
5/13/2023
Satellite Tag Attachment and Deployment
Members of the stretch team will travel to the Port of Nagoya Public Aquarium (PNPA) on June 16 and, over the course of 3 or 4 days, attach the Wildlife Computers Spot 6 tags to 24 juvenile loggerhead turtles that have been raised at PNPA. The turtles will be maintained in sea water at the aquarium for a few days and then they will be loaded on a ship in Nagoya port. They will be escorted by representatives from PNPA and Koichi University who will take good care of the turtles during the voyage and will release them from the ship at a location based on longitude and sea surface temperature. The preferred locations are between 160 and 145 degrees west longitude and a sea surface temperature of 17 degrees C.
5/13/2023
Three of the Spot 6 tags have been tested and passed. They communicated with the ARGOS satellites within an hour of being activated. George Balazs will bring the other 24 tags over for testing some time soon and, once that is done, the tags can be configured for deployment.
5/11/2023
4/8/2023
The Wildlife Computer Spot 6 -387 satellite tags have arrived. George Balazs received them from the factory on 3/7/23. On 3/10/23 George flew to the Big Island and visited Marc Rice to run some tests on the tag and learn the WC Portal and Tag Agent software interface better.
All connection and management tests went well and we are now ready to do the initialization test to confirm that the tags are able to communicate with the ARGOS satellites.
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| Above is a Spot 6 tag, one of 27 we hope to deploy on juvenile loggerheads raised by the Port of Nagoya Public Aquarium. |
4/8/2023
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| Satellite tagging juvenile loggerhead turtles. |
The STRETCH team has been working on a new website that should come online in the next couple of months. This interactive website will feature information about the North Pacific loggerhead turtle, its life cycle and Pacific wide distribution and a description of the STRETCH project and what we hope to learn. There will be brief bios of the STRETCH team members and much more.
The schedule for the project is moving forward also. It is projected that our "turtle deployment" ship will sail some time in June, and we are planning to have the first cohort of 25 juvenile loggerhead turtles (being raised at the Port of Nagoya Public aquarium) equipped with their Wildlife Computer's Spot 387 satellite tags in time for them to make it to the ship for departure. The sat tag attachment team is on standby for a quick departure to Nagoya once we learn of the sailing date for the ship.
Attaching 25 satellite tags will take roughly 4 days to accomplish (doing 8 or 9 turtles each day). Tagged turtles will be placed into an individual "basket" that is in sea water while the rest of the tag attachments are completed. This will keep each turtle separated so that they don't damage the tag antennas before they are deployed in the Central North Pacific ocean somewhere between 140 and 160 degrees west longitude. The site of deployment will depend on the sea surface temperature and the weather (it must be fairly calm to deploy the turtles safely from the ship).
Once the turtles are safely released, we should be getting location fixes from the ARGOS satellites within a few days and those locations will be posted on the loggerhead stretch website as they become available.
The website will be found at http://loggerheadstrech.org once it becomes available and there will be an email address for communications (loggerheadstretch.gmail.com).
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