Rock Fish Age from Otolith

When I caught my most recent monster Verm, my buddy at the beach suggested taking out the otoliths for keepsake.

I had heard about this but never attempted it. I followed this guide on removal and aging process:
https://www.dfo-mpo.gc.ca/science/species-especes/otoliths/students/removal-prelevement-eng.html

I had trouble locating it so I ended up boiling the head and finding them after picking apart the brain. I was able to see how my brain spiking aim is as well so that was cool. I had broken one of the ear bones but the other was nicely in tact. I tried to count the rings on the in tact ear bone and only saw 6 so I figured the fish was 6 years old. But someone on fb suggested that was a little young for such a large fish. I then tried the other method of burning the broken piece and then using a little jewelers lens to count the rings and photograph it.

Eye opening experience on how old these fish are and maybe has shifted my views on take of rockfish. Perhaps leaving the larger monsters to swim as breeders and focusing on the tastier/cleaner 15-20" rockfish. This guy had nice fillets, but when you catch 100+ of these fish a year I dont think there's a need to always keep the big ones. Had a real moral dilemma looking at this (my fiancé is just calling me a pussy tho lol).

Super interesting little study maybe some of you will enjoy it or have done it before. I'm counting maybe 20- 22 rings. (rings form each winter like a tree, you can even tell el-nino years from low growth patterns)

Enjoy!

Very interesting.  Will have to try this out.  Thanks.

I agree w/your fiancé 

Very cool! I agree that it often makes sense to let the big ones go. The smaller fish are also lower in mercury.

20-22 years fits the curve for your fish's size. I don't need to keep lots of rockfish so when I keep fish I usually only keep lings. A 20+inch vermillion in california is an old fish and an important breeder for the species. At this point I have cnr probably 100 or so 20 inch class verms, I just would rather catch more goldfish than eat goldfish. I still remember the first big verm I ever caught, something about the bright orange color as it comes up from the depths, magic. Hope the stock remains in a good place so others can experience it as well.

Rough stats
20-22 inch verm: ~20yrs old
24-30inch lingcod: ~5-7yrs old
23inch cabezon: 10-11yrs old
I think coppers age similarly to verms but am not 100% sure

All of these ages are assuming the fish is female, if it's a male then add 10 to verm, 3 to ling, 10 to cab.

Aside from the prolific spawning and old age of large Vermillion, I find the oldest ones full of worms

It was heartbreaking tossing the infested fillets of my PB verm I caught at Pigeon Pt

I got over it tho as I "tossed" them to the chickens   

I figured as much as to the approximate age of a verm that size, but it is very cool to see it up close like that.

I saw a person at the dock in the Santa Cruz harbor several times this year who was doing research on rockfish. She wanted to remove the otoliths, along with taking various measurements. I talked to her for a little bit about her research, which it sounded interesting. Unfortunately, I didn't kept any rockfish on the days that she was there, or I could have gotten an accurate age for them...

Last winter I got to see some Montana Department of Fish, Wildlife and Parks staff remove otoliths from some kokanee I provided to them.

For the last fifty years there hasn't been any limit on kokanee in Georgetown Lake, because the lake is overpopulated with kokanee, which results in smallish kokanee.  In the winter of 2020-2021, the kokanee numbers were down a bit, but the good news is that the senior class of kokanee (the kokanee which were going to spawn in Fall 2021) were bigger than the typical Georgetown Lake kokanee.  A FWP fisheries biologist concluded that the large size of the kokanee indicated that the kokanee population was getting too low, and without any consultation with local anglers or public hearing he recommended that the Montana Fish and Game Commission reduce the Georgetown Lake kokanee limit to 20 per day and 40 in possession.  We heard about this change in February 2022, and it was effective April 1 2022. There was an immediate huge uproar from anglers, and a couple of us pursued efforts to get the decision reversed and the limit removed.  I sent an e-mail to each of the Commissioners explaining that during the 2021-2022 ice fishing season, not only were there plenty of senior class kokanee, but there were huge numbers of junior class kokanee.  I cited many examples of days when myself and ice anglers I know caught large numbers of kokanee, consisting almost always of  three times or more as many junior class kokanee as senior class kokanee.  For example, one day I caught 63 junior class kokanee and 19 senior class kokanee (see the picture below).  This, we argued, showed that the kokanee population was roaring back from a brief dip. And I sent the commissioners a link to a YouTube video I took showing kokanee swarming under my ice shelter.  We pursued efforts to uncover the basis for the fishery biologist's recommendation, including formal freedom of information act requests, and found that the biologist's basis for his recommendation was disturbingly weak.  In the course of my discussions with the biologist, he asked me to bring him some kokanee so he could age them, and figure out the ages of the big and medium sized kokanee.  So I got to see them remove the otoliths from the kokanee I brought in.  Kokanee otoliths aren't very big!

We got the question of whether to eliminate the kokanee limits on a Commission agenda, and got it all politically wired before the meeting. The commissioners voted unanimously to remove the limits and go back to the no-limit policy which had been in place for the last fifty years, effective immediately.

Here's pictures of the biologist removing otoliths from my kokanee, one of the pictures I sent the commissioners showing the disparity between the numbers of senior class kokanee and junior class kokanee last winter, and a link to the underwater video I sent the commissioners.

Rough stats
20-22 inch verm: ~20yrs old
24-30inch lingcod: ~5-7yrs old
23inch cabezon: 10-11yrs old
I think coppers age similarly to verms but am not 100% sure

All of these ages are assuming the fish is female, if it's a male then add 10 to verm, 3 to ling, 10 to cab.

This really helps to put things in perspective. As a beginner, I haven’t caught any big rockfish yet but I’ll definitely remember this when I do.

Check out this NOAA report about age and how many young produced

Thanks adamhelm67. Do you have a link to that article? I’m wondering if those numbers of young are cumulative over the lifetime of the fish or if they’re young produced per year.

I think this is the article:

https://academic.oup.com/icesjms/article/71/8/2171/748104

The issue of intermittent recruitment brought up in that article is an interesting one: in some marine fish populations practically all of the larva die most years, but every once in a while the currents, plankton, temperatures, etc. line up right and a large number of larva survive. Over a 30 year period, most of the fish may have come from a single good year. In this type of scenario having long-lived spawners is important. Here is one example: https://academic.oup.com/icesjms/article/71/8/2088/749525?login=true

Great post, love seeing that pic of the rings that's cool!  Have some WSB stones I will try and find and look at the rings.  The ages of rockfish wrt size has also made me want to conserve the big ones for breeding.  Like a China rockfish which can live a long time, but doesn't grow very big, so I always release them.