Adult green turtles really like to spend time at the Virgin Islands, and why not? There’s sun, clear water, nesting beaches and seagrass.
Photo: By P.Lindgren – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=27611674
We tagged some of the nesting females on Buck Island, a small island off the bigger island of St. Croix. These satellite-tags beamed location data to space and then back to our computers, where we saw that some of these turtles migrated away after nesting – in typical sea turtle fashion – and some stuck around. In fact, 7 of the 10 we tagged stayed in shallow, near-shore waters around St. Croix and Buck Island, while only 3 made long-distance migrations.
This was the first time green turtles from this area (considered a unique management unit) were shown to have this limited migration. It’s important for natural resource managers in the area to know about these movements – or lack thereof – so they can effectively design their management strategies.
So why do some stay and some go? Well, what do you think?
Check out the full article below:
Hart KM, AR Iverson, AM Benscoter, I Fujisaki, MS Cherkiss, C Pollock, I Lundgren, Z Hillis-Starr. 2017. Resident areas and migrations of female green turtles nesting at Buck Island Reef National Monument, St. Croix, U.S. Virgin Islands. Endangered Species Research 32:89-101. doi: 10.3354/esr00793
Photo from Wikipedia
We have a new paper out, published in Endangered Species Research, on juvenile green turtles from Dry Tortugas National Park.
Using accelerometers, we assessed both depth and ‘overall dynamic body acceleration’ for the turtles. These two factors showed activity during the day and resting at night, whether or not the turtles stayed in shallow water or traveled to deeper water.
From this, it appeared that traveling to deeper waters at night (as some turtles did) was all about resting. So why do some turtles rest in shallow water and some in deep? Well, it turns out the turtles resting in deeper water got more bang for their buck – they were able to get longer resting dives.
Living in an underwater world means considering sleep differently than you or I might. They need to balance out their bouyancy, which changes depending on how much air is taken in. A larger animal can take a larger breath to fill larger lungs, which mean the animal must go deeper to reach neutral buoyancy. Once there, they can rest longer with all that oxygen stored up.
As a growing young turtle, rest is important. It seems that as they get larger, these turtles are willing to expend more energy to travel to deeper waters AND face potential risks associated with that – sharks are in the area for example – in order to get better sleep.
Read the article online for more.
The full citation is:
Hart KM, White CF, Iverson AR, Whitney N (2016) Trading shallow safety for deep sleep: juvenile green turtles select deeper resting sites as they grow. Endangered Species Research 31: 61-73.
Since the summer launch of sonomawildlife.org, the website I co-created, we’ve been busy writing about crickets, stars, beavers, porcupines, watershed clean-ups, and newts, with more posts on the way! It has been really great to create a central place for Sonoma County wildlife issues and education.
What’s next for the site? We are currently on the look-out for people interested in contributing and are working on some social media efforts to further our outreach capabilities. We hope to widen the community involvement in the coming year! If you want to get involved, please contact us – see the About page on the site.
I am really excited about the launch of a new website that I co-created!
The idea of the website was to create a central place for the Sonoma County community to share knowledge about our wildlife neighbors. We hope to connect county residents to the landscape around them, educate about the wildlife that coexists with them, offer opportunities to get involved in wildlife projects, and inform about local wildlife conservation issues.
I will be writing and editing for the site and hope that it will be a useful tool for the people of Sonoma County. Please go and check it out at sonomawildlife.org!
Three new publications out!
First, Guru Magazine has published my article, “Light Sleepers: Why you need to get your sleep, and your light,” about something on my mind a lot during the first year with my new daughter: sleep deprivation. I go over why it’s so important to get those Zzzs (unless of course you LIKE hallucinating and walking into walls, in which case, don’t bother with this article).
The next two were articles published in scientific journals. “Habitat selection by green turtles in a spatially heterogeneous benthic landscape in Dry Tortugas National Park, Florida” was published in Aquatic Biology. This one is interesting because it mixes two telemetry methods: satellite tracking and acoustic receivers. With these methods, we look at what areas turtles prefer and get clues as to whether turtles spent time with (or avoided) each other. Acoustic data in particular can be tricky to work with, and this paper offers up some ways of working with it.
“Hawksbill satellite-tracking case study: implications for remigration interval and population estimates” was published in Marine Turtle Newsletter. I am extra excited about this one because I was first author. In this paper, we talk about Shuli, a hawksbill turtle tagged in the US Virgin Islands . After nesting there, she migrated all the way to the Bahamas before returning to nest again. What was interesting about Shuli was that she nested on a different beach upon her return. In the paper, we talk about how this has implications on counting turtles to get population sizes and also on our understanding of how often individuals nest.
Read one, read all. Learn a little about yourself, learn a little about the natural world.