If I am reading that graph corrctly,on the avg the adult male/juvenile ratio to adult female is 15 to 1,lol.
Either you guys are doing a fantastic job of avoiding the catch of adult females or there is something buggered with that study.
My very best years ever on my line is 8 to 1.I strive for 4 or 5 to 1 and quit early in the years when it goes below 4 to 1.
Will normally have good enough numbers in a month of trapping to make that decision.

16.7 to 1 is the average.

The trapper tags the lower jaw with the sex. Maybe trapper can't tell the difference.

I suspect something going on with the reporting /submissions,
In years of high juvenile numbers I will bring in my stats and skulls to the fur tech to raise the quota on my RTL's
With lynx it is pelt size ratios to determine number of juveniles in the harvest.
We had strict quotas on fisher years back.The trappers asked the fur tech if a study could be done to see what the ratios in the incidental harvest of fisher in marten sets was.
All trappers in the district submitted their fisher skulls,and we had all teeth sectioned.
The study was repeated over a 3 year period.
Turned out that marten sets were fairly selective for juvenile dispersing fisher at a 9 to 1 ratio over adults of both sexes.
This study resulted in all incidental fisher catches (which had been increasing over the years with the overall forest succession)were used to adjust the quotas.
Trappers now had more realistic quota adjustments made permanent on their ground that reflected the shift in the population dynamic on the land.

Main point being that trappers working with MNR in an honest constructive manner can benefit trappers and the resource.

Things are a little different over here in Maine. First off it is not uncommon to have three or more trappers trapping the same areas. For as long as i can remember the season is two months long, November & December. Until two years ago we had a 25 marten & 10 fisher limit. Now the limits are 25 & 25. Limits makes no sense as many families have two or more people tagging the animals that one trapper catches.
For 2006 - 2015 the average catch was 2174 marten & 1067 fisher. For the past six years the averages have been less than 800 marten and less than 500 fisher. So much for management, The MIFW says the declines are because of less trapper effort. They may be correct or they may not be correct. I do know that 15 years ago our bear hunter would see marten coming to the bear baits. Sometimes three or four marten at the same time. For the past five years I can't remember one hunter seeing a marten at a bear bait.

Picked up another marten today.
I set out 3 more boxes on my trail into camp the other day.I can check them when I go to the camp every couple days to put up wood and do chores.Weather is a bit warm yet to set out a good marten line.Crazy weather for this time of year,plus 15c today.i remember walking to high school back in the early 70's first week of November checking under ice muskrat sets. It was 20c below in early Nov.Hoping for colder weather to settle in mid november so I can activate some marten sets on the North line.
Got 4 marten boxes out now including the demo set.
This is another juvenile male,a nice dark mahogany colour,I will confirm age later when I look at the temporal muscle coalescence.

Confirmed,another juvenile male marten.

Okay, can you please explain how you can tell?

Temporal muscles have not coalesced on top of the head.

I’m guessing the Uterine horns are the Uterus without looking it up. Eggs will implant there and grow.

I’ve seen pregnant dogs get spayed and the uterine horn can have multiple fetuses on each side. They look like golf balls saved ot.

Very good information here, thanks for sharing

Ok, so assuming the purple muscles each side of head (temporal muscles?) are same color (or at least lighter) than surrounding muscles? Good info, thanks. Is this a tell for other animals as well?

Only marten as far as I know.
You can tell the older an animal is by the saggital crest that forms between the temporal muscles on the top of the head.Older fisher especially get a large saggital crest when they get older.
But I believe only on marten can it be used as a guide to differentiate between adults and juveniles.
It is fairly accurate with male marten,but it takes a bit of experience to use it for the females.

Great post, I learn a lot from your posts.

Some fisher heads:

Did you have those aged by tooth sectioning to see if the temporal muscle coalescence progression correlates with known age parameters?
When we did our 2 year study on fisher with our local fur tech,the teeth were extracted for aging as it was felt that temporal muscle coalescence was not accurate on fisher.

No tooth ageing was done. Maine now requires tooth submittal from all fisher & marten. Maybe I'll compare tooth ageing too temporal muscle coalescence. It will take about a year after submittal to have any results.

All the science says it is unreliable in fisher.
There are different ways to get an idea like total head circumfrance, overhang of the saggital crest etc but unlike with marten,none are accurate enough for meaningful assesment.in all sex and age class.
Be interested in what you find out.