Just Curious

[MKern]

With all this talk about fish identification lately, I got to looking at some of my pics.
Why do some brookies have the black and white on the pectoral fins and some do not?

Is it sexual maturity? -- the first pic is a fish that is about 7-8 inches.
Is it genetics?
Is it fin size? -- The fins in the 1st pic are way larger than the 2nd.

 

[TimMurphy]

Dear Mkern,

I think it has to do with age and maturity myself. The first fish is considerably older than the second, you can still see the parr marks on the second fish. On the second fish you can also see the beginnings of the white and black edges on some of the fins. I'd be willing to bet that as the fish ages the fin markings will become more pronounced.

Regards,
Tim Murphy :-D

 

[live2fish]

I can see parr marks (vertical bars) on both fish. Think the reason you don't see the stripes on the pectoral fin in the second pic is the way the fin is lying. You can see the stripes on the pelvic and anal fins in the second pic. Got this from the PFBC site.

The pectoral, pelvic and anal fins are pale to bright-orange with a white leading edge followed by a black stripe. In spawning males, colors become more intense and the belly becomes deep-orange. At maturity, wild brook trout may be from five inches to 18 inches long, according to the availability of food in the home stream.

 

[Chaz]

Unless they are stocked brookies they WILL have black, white and red or orange on all of their fins. Having said that, there is variation in the amount showing and a quick look or a bad photo will not show the colors well. The fish in your photos both have the colors, the bigger fish it is more evident. Any fish that doesn't have the black and white is either not a brookie or is a stocked fish with worn fins. If it looks like a brookie a little bit and doesn't have the black and white it may be a tiger, PFBC is stocking more of these weird fish this year for some reason.
I don't believe age plays a role, but as with all coloring of brookies 2 significant factors are diet and the camoflage ability of trout, very pale fish lying out in the bright sun will always have less intense fins.