Otoliths recoveries

[gstours]

  Many fish that we catch have the otoliths in the back part of the head and these can be removed for examination.  The halibut in the north West have relatively small ones compared to rockfish.
   With out an explanation on the purpose of the otoliths (later, ok?).   Here's a pair of earrings that I made for a friend,s wife.    See what you think 🤔

[gstours]

Every fish has a pair of these floating in clear fluid in a small cavity in front of the spine.  Many things can be learned by examining the rings and spacing about the history of the growth of the animal.

[gstours]

This is a new hobby for me,  a good indoor project when it's snowing 🌨.

[alantani]

allison says thanks!!!!!! 

[Tightlines667]

I like them. 

[MarkT]

I didn't know Halibuts had them. I always think White Sea Bass when the subject of Otoliths comes up.

[bhale1]

well, Gary managed to give me homework, even tho im not in school anymore........Okay Google, "what are otoliths in fish"
Brett

edit.....Uhm, this is going to take some time
Apparently its an organ that grows in the fishes ear...helps with orientation, and balance..much like an internal compass. Also exhibits growth rings, much like a tree to help determine age and growth rate,,,,after that Im lost....
Brett

[Tightlines667]

well, Gary managed to give me homework, even tho im not in school anymore........Okay Google, "what are otoliths in fish"
Brett

Ear bones.

All fish have them.

They allow them to maintain balance/orientation, and help with hearing, especially low frequency sound.  They are made of mostly calcium, and built up in layers rouggly equal to the fish's growth rate.  We scientist can use this fact to count the annual or is some cases, daily growth rings in order to age fish.  Cold water species that happen to have the largest otoliths and biggest annual differentual growth rates are best aged using otolith cross sections.  

I once did a research project on aging Lingcod by otoliths and spines, and compared age & growth rates and aging methodologies between samples from southern California, Oregon, and Alaska.  Turns out spines work just about as good for aging this species and they are easier to collect/prepare/read.  Also, growth rates are inversly proportiional to latitude (a proxy for water temp).  However, the slower growing fish in AK are easier/can be more accurately aged especially with older fish where some error exists with both methods.

I also did a diet study on those in Coos Bay.  Turns out they love octopus.

John

[oc1]

Those are about the most unique thing I have ever seen Gary.  Really ingenious.  

If you put a hatchery fingerling in tetracycline for a few hours it will put a stain ring on the otolith that will fluoresce under UV light when the otolith is sectioned and the mark will last forever.  It's a safe and easy way to mark fish without using tags or fin clips.  In the 1950's they started telling pregnant women not to take tetracycline antibiotic because it stains the developing baby's teeth.

-steve

[gstours]

I just started removing these late this year while fishing halibut.   🎣 My friend Ken is very good at locating them.  A rubber mallet and a large chefs knife 🔪 is pounded in at 90 degrees to the spine just behind the back false gill plate.  Clear thru the hollow cavity.   There is one on each side in a separate cavity.
   These can be easily removed with a tweezers or small tool.
The fish uses these otoliths to send information to the brain 🧠 to sense orientation, speed, and other things by rubbing hair like sensors in the cavity of clear fluid.   Pretty cool actually!🤔
   Something tells me that all fish do not have otoliths.   Somebody out there will know?

[Hardy Boy]

I have sampled thousands of fish for otoliths; all types of ground fish but mostly rockfish species, sole species, greycod and pollock. I was a groundfish research tec for over ten years. Some fish have small otoliths for their size (salmon and blackcod = very small otoliths) and others have very large otoliths for their size (pollack = huge otoliths). Elasmobranks do not (sharks and rays) have otoliths.


Cheers:

Todd

[Gfish]

John(tightlines) stated it above "All fish have them". Only bad thing bout otoliths is, you gotta kill the fish to get 'em. Scales which are much harder to read, can age fish as well( rings close together = slow(winter?)growth). John also mentioned using spines, never heard a that one, but it don't sound like you'ed have to kill 'em for that, either.
I'mina stick to sharks teeth for jewelry.

Edit, Ok sharks, etc.(elasmobrancks), don't got 'em.

[Hardy Boy]

We use dorsal fin rays for lingcod (better than otolith for aging) and the spine of the dogfish (shark) to age those species. For other sharks and rays you use the vertebrata (for the species here in BC). It is also amazing how the fish can be different to cut; for example: rougheye rockfish have an easy head to cut with a knife while the same size yelloweye is very hard and may reequire a hacksaw to cut.


Todd

[Fishy247]

Years ago, I started checking fish for otoliths. I was working a partyboat in Marina Del Rey and had access to lots of carcasses. Sand bass and rockfish had very delicate ones, like the ones Gary posted. White seabass have very solid, roundish ones. What kinda surprised me was that white croaker(kingfish in NoCal, tomcod in SoCal) also have them and they are almost identical to those out of seabass, just much smaller. Very cool stuff!

[Dominick]

Amazing!  The information on this site is beyond interesting.  Keep up posting the off-beat stuff.  Fascinating.  Dominick