Our 18.1 inch rule in the Regs.

[mad scientist 140]

37 minutes ago, AB said:

Perhaps the Mad Scientist could help us understand what the typical growth rates are in terms of inches per year are for these types of systems in the Tbay area, and the typical length of males and females are when they first reach maturity.

 

 

 

I don't have access to up to date data, but based on 160 walleye netting projects conducted in northwestern Ontario between 1993 and 2001, 50% of female walleye are mature at 441mm total length, and 90% are mature at 483mm (17-19 inches).  50% of males are mature at 360mm and 90% at 397mm (14 to 16 inches).

 

Describing the growth rates is more difficult, because it's not a straight line; fish grow most rapidly in their first year, and juvenile fish grow more rapidly than mature ones.  Further complicating it, female walleye tend to grow faster and larger than males...so you can't easily measure a fish and directly convert inches to age.  But further to the previous paragraph, 50% of female walleye are mature at 4.78 years, and 90% at 6.0 years; for males it's 3.49 and 4.62 years, respectively.

[RickS 19]

Here is a nice summary about walleye growth rates in Manitoba-- which should be a reasonable approximation for northwestern Ontario (source was http://www.aikenslake.com/news/a-look-into-the-growth-rates-of-walleye).  As Mad Scientist pointed out, the growth rate slows substantially as a fish ages and by the time it exceeds 5 years of age it is typically only adding 1-2 cm/year.  But the good news is that fish "add" most of their length in the middle of the body (as opposed to adding most of it at the snout or tail) so that additional 2 cm of length can actually add a surprising amount of mass (weight).

 

AGE

•1 – In their first year, a walleye will grow to around 13cm (5”) and weigh just .2 lbs. The males will be slightly bigger and will continue to be for several years.
•2 – Generally, the walleye will be at about 20cm (8”) in its second year of life. It will weigh slightly less than half a pound.
•3 – At this point the male walleye will be considered mature and will be about 26cm in length. They will weigh about .6lb.
•4 – This is the age in which female walleye will begin to outpace males in terms of size. On average, the walleye will weigh just shy of a pound and be 31cm (12.3”) in length.
•5 – At age 5, female walleye are considered mature and continue to grow more than the males. The average weight of a 5 year old walleye is a pound and in terms of length they will reach about 36cm (14.2”).
•10 – When they reach age 10, walleye will typically weigh about 2.6lbs. and will be about 49cm (19.1cm) long.
•15 – In terms of length, a 15 year old walleye will be about 58cm (23”). For weight, they will be 4.5 pounds.
•20 – At this point, the walleye population will be mostly female. They will weigh about 6.7 lbs. and be around 66cm (26.2”) in length.
•25 – For those walleye that live this long, the average weightis 9.4 lbs. and the average length is 74cm (29”).

 

 

Harvesting walleyes smaller than 25cm means you are removing fish before they've had any chance to spawn.  Harvesting fish in in the 30 cm range means they have probably bred at least once but there is no particular way to know whether you are harvesting males or females.  Once a walleye reaches a size of >50 cm, there is a good bet that it is a female.  These larger females produce significantly more eggs than their 30-45 cm cousins and that is why it is a particularly good idea to have some limits on the number and maximum size that can be harvested.  

[Bobber Down 921]

http://wildernessnorth.com/wordpress/wp-content/uploads/2014/09/FishGrowthChart.pdf

[Some Old Guy 968]

I already knew the approximate age for different sized walleye. I already knew about what classes of lakes hold walleye, and I might add that quite a few also hold lake trout and are either oligotrophic or right on the edge of mesotrophic/oligotrophic type waters.

 

And it does come down to the decisions of what an angler takes home. (and there is nothing wrong doing what I say next as you are within the law to do so) anglers are removing walleye 16 -18 inches long. I have no problem with this at all. I'm just noticing a decline with this size of walleye in popular systems. Then I just thought of possible long term affect on our walleye populations.

 

Roger

[RickS 19]

I don't think you need to worry too much as long as you continue to see 18-20" fish showing up.  Since adult walleyes generally grow about 1-2" per year, seeing fish in the 18-20" size class means that at least some are recruiting through the "danger zone".  But if you stop seeing those 18-20" fish and instead are only seeing big fish (and probably fewer of them) then you may have a population that is in trouble.

[fishman1 164]

Things are quite fine at the moment, if it ain't broke, don't fix it. 

I am more than happy to eat the 14-15 rather than those just u der 18

roger, you use whitefish as an example saying there seems to be total yer classes missing.

with the pressure that lake gets, I'm surprised there's Nything left.

you can have all the just unders you want, leave me the eaters!

[mad scientist 140]

17 hours ago, RickS said:

Harvesting walleyes smaller than 25cm means you are removing fish before they've had any chance to spawn.  Harvesting fish in in the 30 cm range means they have probably bred at least once but there is no particular way to know whether you are harvesting males or females.  

 

Size at maturity is a little bigger in the report I'm citing, but there's lots of variability across the landscape.  Regardless, the other factor that folks should consider is that there's naturally very high natural mortality in juvenile walleye...so most of those fish you catch under 25cm aren't likely to survive to spawn anyway.

 

Based on some generalized survival rates, if you start with a million walleye fry, you're only going to have 332 fish reach age 3, and 150 reach age 4.  

[Foz 25]

I have been fishing Lac des mille lacs for many years. Years ago there was regulations put in place where walleye have to be greater than 13 inches to keep. I am finding that this year I am getting many in the 16-18 inch range. Of course a lot in the 10- 12 range as well and a few that are over 20 inches. It may be just the area of the lake I am fishing but I am finding that especially this year, I am having more consistency catching these 16- 18  inch walleye.