John Hlavin
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marinebiojohn.bsky.social
John Hlavin
@marinebiojohn.bsky.social
🙌🏼 UMiami Shark Research PhD student
🦈 Marine science communicator
🔗 doi.org/10.1002/ece3.71473
Oh my gosh that’s really cool! Thank you for inspiring it!
August 5, 2025 at 3:28 PM
Doing really well! Completely lucked out stumbling into the world of shark ecology under some really great mentors, including David! Got excited seeing your name pop up on my feed, I’ll always remember your class, so unique compared to the rest of the bio courses I took! How are you?
August 5, 2025 at 3:25 PM
Woah, crazy collision of past and present worlds!! @caraocobock.bsky.social taught me an absolutely awesome course on biological anthropology at ND! Fall 2019 if I’m remembering correctly
August 5, 2025 at 3:07 PM
Thanks David! The trap fisheries will not be thrilled if true 😅
July 10, 2025 at 9:10 PM
We swabbed their bums for trace amounts of fecal DNA, and when tiger sharks voluntarily regurgitated some material during working ups (as they are known to occasionally do) we opportunistically collected that vomit too! No pumped stomachs here 🐅🦈
July 10, 2025 at 9:09 PM
Thanks Carlyanne!! 🐅🦈
July 10, 2025 at 9:06 PM
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)
July 10, 2025 at 7:41 PM
Thanks for sharing!!
July 4, 2025 at 12:25 PM
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...
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
Maybe this is an appropriate step for prestigious high impact journals like Nature, which should be the epitome of rigor and which young scientists may not be targeting right away anyway, but it might further dissuade that “deep three pointer” attempt. Anyway, thanks for prompting this!
June 27, 2025 at 12:43 AM
I look at peer review like refining precious metals. Initial submissions should be allowed to be lumps of (well-reasoned and ethical) ore. When researchers are young or venturing into a new discipline/method, initial submissions open to scrutiny might discourage ventures beyond comfort zones.
June 27, 2025 at 12:43 AM
So with that in mind, I think there’s already an inner voice of imposter syndrome whispering doubts of whether my published work will impress the veterans in my field enough. So for those vets to also be able to scrutinize a paper in its infancy is intimidating and might poke that insecurity.
June 27, 2025 at 12:43 AM
Yes, actually! Most if not all of it does resonate with me! Thank you for the thoughtful response. I think my initial hesitation comes from a place of being a very early career scientist with only a few experiences of having my own work reviewed / being a reviewer.
June 27, 2025 at 12:43 AM
All for double blind/disclosing reviewer identities, but total transparency of initial submissions, revisions, and comments/responses feels a bit like making artists hang their scrapbooks up next to their masterpiece… interested in your thoughts!
June 26, 2025 at 10:01 PM
Using multi-tissue stable isotope analysis, we show that they strongly depend on the nursery for their first two years before switching to coastal foraging, initially only seasonally in subadults who use more bay resources during the wet season when adults are more abundant in local coastal areas 🦈
June 16, 2025 at 7:34 PM
🙋🏻‍♂️
June 13, 2025 at 12:20 PM
The sharks would probably hear you wishing them a great weekend better if you slammed their tank shut after
May 23, 2025 at 11:11 PM