Thread: Friday Fish Factoid #3
02-28-2014, 03:25 PM #1
Friday Fish Factoid #3
I won't ruin your fond memories of Disney movies with this one.. but I will start it with a Riddle!
How are Fish and Trees Alike?
The answer is Age rings!
Fish scales show the age growth of fish in rings just like trees show their growth in age rings! Biologists can (and often do) use this method to determine the age of a fish.
02-28-2014, 03:30 PM #2
- Join Date
- Mar 2013
- Blog Entries
Cool. I didn't know that tho I wonder how they would age a scaleless fish? Teeth?
02-28-2014, 03:30 PM #3
02-28-2014, 03:34 PM #4
When I worked for the Ministry of Natural Resources back in the day, one of my summer jobs was to record the ages of pickerel/walleye via scales. Didn't take long to get squinty-eyed doing that! Tho I did get to use a microscope to do it.
02-28-2014, 03:37 PM #5
A new learning.. Thanks for sharing :)
02-28-2014, 03:45 PM #6
For scale-less fish, they use the cleithrum - a bone behind the gills. The lines on it indicate age.
Well, it works for any fish, but scaling can be done on a live fish, whereas the cliethrum is used for dead specimens.
If you don't want to kill the fish, you have to use the less accurate weight/length to age charts for your area. You can usually find them online.
Last edited by sheamurai; 02-28-2014 at 03:55 PM. Reason: more info added
02-28-2014, 03:52 PM #7
So scale rings are the least invasive method.
02-28-2014, 03:53 PM #8
02-28-2014, 03:55 PM #9
so how often does it add a line - trees are easy because each ring is 1 year. not sure how it translates to fishCurrent tanks:
37G FW - 3 Pearl Gourami, 4 Black Mollies, approximately 20+ Molly Fry, 5 Assassin Snails | 10G Planted FW - 14 Molly Fry, rocks, DW and an Anubias Nana - journal
"We come from the land of the ice and snow" | "I reject your reality and substitute my own" - Adam Savage | What part of "Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn" don't you understand?
How to cycle without fishies!
02-28-2014, 03:59 PM #10
same idea...a line equals a year, you just have to careful what you decide to interpret as a line, as the demarcation isn't as evident on fish as in trees.