John Hlavin
@marinebiojohn.bsky.social
🙌🏼 UMiami Shark Research PhD student
🦈 Marine science communicator
🔗 doi.org/10.1002/ece3.71473
🦈 Marine science communicator
🔗 doi.org/10.1002/ece3.71473
Pinned
John Hlavin
@marinebiojohn.bsky.social
· Jun 16
Nursery Resource Use Dynamics in Great Hammerheads (Sphyrna mokarran) Across Ontogeny
The ecological trade-offs required by nursery dependence are poorly understood. Using multi-tissue stable isotope analysis, this research provides evidence of constrained resource use in juvenile gre....
onlinelibrary.wiley.com
🚨NEW🦈PAPER🚨
Excited to announce my first publication with @drcatmac.bsky.social on the ontogenetic and seasonal trophic ecology of great hammerheads around the Biscayne Bay nursery! Linked below
onlinelibrary.wiley.com/doi/10.1002/...
Excited to announce my first publication with @drcatmac.bsky.social on the ontogenetic and seasonal trophic ecology of great hammerheads around the Biscayne Bay nursery! Linked below
onlinelibrary.wiley.com/doi/10.1002/...
Reposted by John Hlavin
#AES25 #JMIH25
Finally, @marinebiojohn.bsky.social John Hlavin, Reconstructing diets of Tiger Sharks in South FL
Finally, @marinebiojohn.bsky.social John Hlavin, Reconstructing diets of Tiger Sharks in South FL
July 10, 2025 at 7:30 PM
#AES25 #JMIH25
Finally, @marinebiojohn.bsky.social John Hlavin, Reconstructing diets of Tiger Sharks in South FL
Finally, @marinebiojohn.bsky.social John Hlavin, Reconstructing diets of Tiger Sharks in South FL
Reposted by John Hlavin
@marinebiojohn.bsky.social at #JMIH25 #AES25
A multi-method approach can help determine the diet of tiger sharks, different methods have pros and cons. Includes data from 67 Tiger sharks- I think I helped get data on 6 of these!
A multi-method approach can help determine the diet of tiger sharks, different methods have pros and cons. Includes data from 67 Tiger sharks- I think I helped get data on 6 of these!
July 10, 2025 at 7:35 PM
@marinebiojohn.bsky.social at #JMIH25 #AES25
A multi-method approach can help determine the diet of tiger sharks, different methods have pros and cons. Includes data from 67 Tiger sharks- I think I helped get data on 6 of these!
A multi-method approach can help determine the diet of tiger sharks, different methods have pros and cons. Includes data from 67 Tiger sharks- I think I helped get data on 6 of these!
Reposted by John Hlavin
Whoa- @marinebiojohn.bsky.social found *cow* and *pig* among tiger shark diet.
(He thinks they were bait in lobster and crab traps)
(He thinks they were bait in lobster and crab traps)
July 10, 2025 at 7:41 PM
Whoa- @marinebiojohn.bsky.social found *cow* and *pig* among tiger shark diet.
(He thinks they were bait in lobster and crab traps)
(He thinks they were bait in lobster and crab traps)
Reposted by John Hlavin
This was a HUGE effort with LOTS of field time and LOTS of analysis – huge thank you to all my coauthors and the many folks who contributed in the field. Very proud of this one. (4/4)
@dr-yannis.bsky.social 🦑🧪🌊🐟
See the paper: link.springer.com/article/10.1...
@dr-yannis.bsky.social 🦑🧪🌊🐟
See the paper: link.springer.com/article/10.1...
Energetic benefits of prey choice for a shark-eating shark - Oecologia
Optimal foraging theory has been used to understand the foraging choices of animals but is rarely applied to large predatory fishes due to difficulties measuring their behavior in the wild. Great hamm...
link.springer.com
June 27, 2025 at 12:57 PM
This was a HUGE effort with LOTS of field time and LOTS of analysis – huge thank you to all my coauthors and the many folks who contributed in the field. Very proud of this one. (4/4)
@dr-yannis.bsky.social 🦑🧪🌊🐟
See the paper: link.springer.com/article/10.1...
@dr-yannis.bsky.social 🦑🧪🌊🐟
See the paper: link.springer.com/article/10.1...
Reposted by John Hlavin
Further coverage, this time by @forbes.com columnist & #shark researcher @melissacmarquez.bsky.social, about the new paper on #hammerheadsharks using #BiscaneBay, #Florida as a #nursery
Column quotes @drcatmac.bsky.social
www.forbes.com/sites/meliss...
Column quotes @drcatmac.bsky.social
www.forbes.com/sites/meliss...
June 26, 2025 at 12:04 AM
Further coverage, this time by @forbes.com columnist & #shark researcher @melissacmarquez.bsky.social, about the new paper on #hammerheadsharks using #BiscaneBay, #Florida as a #nursery
Column quotes @drcatmac.bsky.social
www.forbes.com/sites/meliss...
Column quotes @drcatmac.bsky.social
www.forbes.com/sites/meliss...
Reposted by John Hlavin
A new post from DiscoverWildlife covers the 2025 research from @marinebiojohn.bsky.social and @drcatmac.bsky.social showing tat #BiscayneBay is a nursery area for #hammerhead #sharks
www.discoverwildlife.com/animal-facts...
www.discoverwildlife.com/animal-facts...
A rare shark is seeking refuge in Miami's Biscayne Bay. Here's why scientists just spent 8 years tracking it | Discover Wildlife
A new study reveals that Biscayne Bay is a vital year-round nursery and seasonal refuge for one of the world's most endangered shark species.
www.discoverwildlife.com
June 20, 2025 at 1:34 PM
A new post from DiscoverWildlife covers the 2025 research from @marinebiojohn.bsky.social and @drcatmac.bsky.social showing tat #BiscayneBay is a nursery area for #hammerhead #sharks
www.discoverwildlife.com/animal-facts...
www.discoverwildlife.com/animal-facts...
Reposted by John Hlavin
This is wild:
Recently, I spotted a critically endangered great hammerhead… in the middle of urban Miami. It wasn’t a fluke.
@marinebiojohn.bsky.social & @drcatmac.bsky.social published a study today showing this bay — full of yachts, crab traps, & fishing boats — is a vital nursery habitat. 🌎🦑🧪
Recently, I spotted a critically endangered great hammerhead… in the middle of urban Miami. It wasn’t a fluke.
@marinebiojohn.bsky.social & @drcatmac.bsky.social published a study today showing this bay — full of yachts, crab traps, & fishing boats — is a vital nursery habitat. 🌎🦑🧪
June 16, 2025 at 9:47 PM
This is wild:
Recently, I spotted a critically endangered great hammerhead… in the middle of urban Miami. It wasn’t a fluke.
@marinebiojohn.bsky.social & @drcatmac.bsky.social published a study today showing this bay — full of yachts, crab traps, & fishing boats — is a vital nursery habitat. 🌎🦑🧪
Recently, I spotted a critically endangered great hammerhead… in the middle of urban Miami. It wasn’t a fluke.
@marinebiojohn.bsky.social & @drcatmac.bsky.social published a study today showing this bay — full of yachts, crab traps, & fishing boats — is a vital nursery habitat. 🌎🦑🧪
🚨NEW🦈PAPER🚨
Excited to announce my first publication with @drcatmac.bsky.social on the ontogenetic and seasonal trophic ecology of great hammerheads around the Biscayne Bay nursery! Linked below
onlinelibrary.wiley.com/doi/10.1002/...
Excited to announce my first publication with @drcatmac.bsky.social on the ontogenetic and seasonal trophic ecology of great hammerheads around the Biscayne Bay nursery! Linked below
onlinelibrary.wiley.com/doi/10.1002/...
Nursery Resource Use Dynamics in Great Hammerheads (Sphyrna mokarran) Across Ontogeny
The ecological trade-offs required by nursery dependence are poorly understood. Using multi-tissue stable isotope analysis, this research provides evidence of constrained resource use in juvenile gre....
onlinelibrary.wiley.com
June 16, 2025 at 7:34 PM
🚨NEW🦈PAPER🚨
Excited to announce my first publication with @drcatmac.bsky.social on the ontogenetic and seasonal trophic ecology of great hammerheads around the Biscayne Bay nursery! Linked below
onlinelibrary.wiley.com/doi/10.1002/...
Excited to announce my first publication with @drcatmac.bsky.social on the ontogenetic and seasonal trophic ecology of great hammerheads around the Biscayne Bay nursery! Linked below
onlinelibrary.wiley.com/doi/10.1002/...
🚨NEW PAPER🚨
Congrats to @scrippsocean.bsky.social’s Jack Elstner and team on their new research demonstrating early successes in the application of AI-driven software Ocean Ruler as a citizen science tool for fisheries monitoring!
doi.org/10.1007/s002...
Congrats to @scrippsocean.bsky.social’s Jack Elstner and team on their new research demonstrating early successes in the application of AI-driven software Ocean Ruler as a citizen science tool for fisheries monitoring!
doi.org/10.1007/s002...
Ocean Ruler– an image-based, AI-driven approach to small-scale fisheries monitoring and catch size estimation - Marine Biology
The ubiquity of data-limited, data-absent, and unmanaged fisheries around the world illustrates a significant need for enhanced monitoring of living marine resources beyond conventional agency-led pro...
doi.org
June 12, 2025 at 11:34 AM
🚨NEW PAPER🚨
Congrats to @scrippsocean.bsky.social’s Jack Elstner and team on their new research demonstrating early successes in the application of AI-driven software Ocean Ruler as a citizen science tool for fisheries monitoring!
doi.org/10.1007/s002...
Congrats to @scrippsocean.bsky.social’s Jack Elstner and team on their new research demonstrating early successes in the application of AI-driven software Ocean Ruler as a citizen science tool for fisheries monitoring!
doi.org/10.1007/s002...
Reposted by John Hlavin
Frontiers | Trophic and feeding ecology of whale sharks (Rhincodon typus) using bulk stable isotope analysis
Frontiers | Trophic and feeding ecology of whale sharks (Rhincodon typus) using bulk stable isotope analysis
IntroductionDespite their size, relatively passive behavior, and commercial significance, knowledge of the behavioral ecology of whale sharks remains limited...
www.frontiersin.org
May 24, 2025 at 1:13 PM
Frontiers | Trophic and feeding ecology of whale sharks (Rhincodon typus) using bulk stable isotope analysis
Reposted by John Hlavin
Our two days of “Shark scientist for a day” fundraiser trips raised $10,000 that will go towards providing low-resource Miami public schools with free marine biology field experiences in the future. Thanks to my 20 social media followers for joining us and supporting this important cause!
May 10, 2025 at 10:26 PM
Our two days of “Shark scientist for a day” fundraiser trips raised $10,000 that will go towards providing low-resource Miami public schools with free marine biology field experiences in the future. Thanks to my 20 social media followers for joining us and supporting this important cause!
🚨 New paper 🚨
Go check it out!
Way to go, Emily!
Go check it out!
Way to go, Emily!
I am incredibly excited and proud to share the (open access) publication of my first, first author paper: Diel patterns of symbiont expulsion in Caribbean reef corals are coral species-dependent and driven by symbiont load and photosynthetic performance
link.springer.com/article/10.1...
link.springer.com/article/10.1...
Diel patterns of symbiont expulsion in Caribbean reef corals are coral species-dependent and driven by symbiont load and photosynthetic performance - Coral Reefs
The mutualistic relationship between scleractinian corals and dinoflagellate algae (Family Symbiodiniaceae) is critical to the success of corals on tropical reefs yet underpins their vulnerability to ...
link.springer.com
March 2, 2025 at 6:17 PM
🚨 New paper 🚨
Go check it out!
Way to go, Emily!
Go check it out!
Way to go, Emily!
This was a “look Ma I made it” moment I wasn’t expecting this Tuesday morning. Thanks, David!
Ok, this one I *do* want your help with.
Making a starter pack of shark and ray scientists and conservationists.
There are a lot of folks I missed, help me fill this out.
go.bsky.app/Q1x1gJB
🧪🌎🦑🦈🐠
Making a starter pack of shark and ray scientists and conservationists.
There are a lot of folks I missed, help me fill this out.
go.bsky.app/Q1x1gJB
🧪🌎🦑🦈🐠
November 19, 2024 at 4:19 PM
This was a “look Ma I made it” moment I wasn’t expecting this Tuesday morning. Thanks, David!
Reposted by John Hlavin
John Hlavin @marinebiojohn.bsky.social at #JMIH24 American Elasmobranch Society 🧪🦑🦈
Biscayne Bay is a nursery area for great hammerhead sharks. They start to leave between 140-170 cm in size, expanding their niche without abandoning coastal food sources, varying habitat seasonally.
Biscayne Bay is a nursery area for great hammerhead sharks. They start to leave between 140-170 cm in size, expanding their niche without abandoning coastal food sources, varying habitat seasonally.
July 14, 2024 at 5:41 PM
John Hlavin @marinebiojohn.bsky.social at #JMIH24 American Elasmobranch Society 🧪🦑🦈
Biscayne Bay is a nursery area for great hammerhead sharks. They start to leave between 140-170 cm in size, expanding their niche without abandoning coastal food sources, varying habitat seasonally.
Biscayne Bay is a nursery area for great hammerhead sharks. They start to leave between 140-170 cm in size, expanding their niche without abandoning coastal food sources, varying habitat seasonally.
Hi Bluesky! PhD student here studying shark trophic ecology, with special focus on great hammerhead nursery use.
I’ve had moderate success as a science communicator on Tiktok, Instagram, Snapchat so this is a new frontier for me. Excited to connect with y’all!
I’ve had moderate success as a science communicator on Tiktok, Instagram, Snapchat so this is a new frontier for me. Excited to connect with y’all!
February 21, 2024 at 12:23 AM
Hi Bluesky! PhD student here studying shark trophic ecology, with special focus on great hammerhead nursery use.
I’ve had moderate success as a science communicator on Tiktok, Instagram, Snapchat so this is a new frontier for me. Excited to connect with y’all!
I’ve had moderate success as a science communicator on Tiktok, Instagram, Snapchat so this is a new frontier for me. Excited to connect with y’all!