Timo Rittweg

These tiny amounts of otolith material represent the last few weeks of growth in an individual fish's life. Measuring oxygen and carbon isotope ratios from the powder will hopefully allow us to reconstruct their wintering grounds at sea 🌅🐟

Which is why I spent two weeks at the National Oceanography Centre (NOCS) in Southampton, extracting tiny amounts of powder from twaite shad (Alosa fallax) and smelt (Osmerus eperlanus) otoliths with a diamond drill 👨🏻‍🔬🔬

Otoliths (calcium carbonate stones that form in the inner ear of most fishes) reflect the elemental signature of the surrounding water in sequential year rings, offering a unique opportunity to reconstruct fish movements back in time.

One week of otolith drilling later... Working on a project investigating the distribution and ecology of non-commercial migratory fish, one part of the project aims at reconstructing marine movements. Our first idea was looking at otoliths! 🐟🐠🐡

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Image: twaite shad (Alosa fallax) otolith

The chronology can now also be used for other fishes in the Baltic, and hopefully contribute to improving and ground-truthing established aging protocols!

Turns out, these tiny pelagic can get OLD 👴🏻 herring otoliths were validated up to an age of 22 years, and sprat otoliths up to 18 years! 🐟

We used 1+ cod for multiple decades to establish a chronology of 14C decay rates for the Baltic Sea, and aligned high-confidence herring and sprat otolith reads to validate it's use

New paper out, led by Allen Andrews, establishing a bomb radiocarbon chronology of the Baltic sea, and validating some Baltic fish aging protocols in the process --> doi.org/10.1093/ices...

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To extend everyone’s little sturgeon break… very chill baby sturgeons sturgeoning.

Otolith cake pudding to finish the post (also made by @crocodiledunphd.bsky.social)☺️

But just as important, a supportive family and frinds. Big shoutout also to @crocodiledunphd.bsky.social for proof-reading the thesis, listening to my ramblings (i.e. my defense talk),and being allround supportive and wonderful!

Impossible without a great team! (goes for a lot of things, not just PhD theses) 😅

Convinced them in the end it seems 🤓

Wait, I can explain...!

The committee, sharp questions locked and loaded! @profchrisharrod.bsky.social @rarlinghausfish.bsky.social @clivetrue.bsky.social

PhDone! Huge thanks to an amazing team, the Boddenpike gang, my inspiring supervisors & mentors, and everyone else involved in the project. Couldn´t have done this without any of you! Looking forward to many more exciting years of fishy research! 🧪🐟#PhDone #FishSci #Researcher

This👇

Little milestones which don´t mean a lot in the grand scheme of things, but I´m chuffed to have crossed 100 citations on my google scholar & RG profiles! Testimony to the fact there´s some people out there reading my stuff, thinking "well, that seems to make sense"! 😆🐟🧪

Phoebe wearing a white fluffy jacket (it’s night time, it is clearly very cold) is holding a gorgeous fish in front of her. It is mottled yellow and black and has a long tail and has inspired many folk names.

Hi #fishsky - calling all fans of the fish Lota lota or #burbot. What common names do you know for this species (in any language) and why is it called that? I have heard some very funny common names in US English and German for the species and would LOVE to know some more! #fishtaxonomy

As everywhere, it´s not great... 😅 I do have high-res maps on obstructions, however, and will measure species-specific passage efficiency in due time. Thanks for the feedback!

Thx, that´s very helpful

Hey James, it´s a mix of occurence data and abundance. But mostly it´s abundance of fish species at locations (with effort measure) across German river systems over the last two decades. Constraints are that sampling wasn´t constant throughout the year, and methods were poorly standardized.

Question for any ecology peeps that might read my tweets (blues? Do we have a new word for this by now? 😅): Do you know of any courses teaching species distribution modelling techniques (correlative/causative) that you can recommend?
Grateful for any advice (baby pike pic for attention) 🙏🧪

Opt out tomorrow!

Harbour of Rostock in the back, in the front you see a fishing line with one of our new pearls.

two people stand onboard of RV Solea in the harbour of Rostock preparing the setup for echo sound tests.

three people working on the bow of RV Solea to test the new pearls with the echo sounder.

🎬 Lights, camera, action! 🌊

Last week, our new design pearls were in the spotlight.

Part of our team was onboard our research vessel, testing its underwater visibility under the frequency of harbor porpoise clicks. Using an echosounder, we simulated these signals—and the results? Very promising! 🦑

A zebrafish on white background and a closeup of the zebrafish eye and face

Interested in automated length and morphological measurements? Check out our new app and preprint!

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ecoevorxiv.org/repository/v...

Hey, higher ed leaders, this is what acting with courage looks like. Give it a try! We’ll support you.

Great piece about archival tissues by @otolithgirl.bsky.social. If you haven´t already, give it a read! 🐟🐢🦉🐋🧪

Trophic ecologists who work with stable isotopes I bring you a{nichetools} - a complementary package to {SIBER} and {nicheROVER} that allows you to work with data objects created by either pkg. Check it out!
benjaminhlina.github.io/nichetools/

#rstats #stableisotopes #foodwebs

Zoe (author of post) is holding a beak of a giant octopus squid, a mysterious species we know little about.

Congrats Erica Durante for publishing amazing research (+ your 4th PhD paper!). Erica developed methods to extract estrogen & progesterone from cephalopod beaks. Now we can get lifetime reproductive data from species we know little about! @aslo.org
aslopubs.onlinelibrary.wiley.com/doi/10.1002/...