Change in bite from year to year

I just got back from my annual 2 week trip to Astor. For the last 8 years I have fished the river south of the bridge, Dexter, Tick run to Woodruff. I always go the last week of Feb through the first week of March.
I only troll for specks, but it seems what worked last year does not work so well the next year. Last year I was killing them with Hal flys / Jiffy jigs in orange/green/orange and red/blue/white. This year I could not get a bite on them. When the fishing is slow I don't wait long to try other colors and jigs to see what they want. This year it took me a couple of days to figure them out. In the past I have had little to no luck with road runners, all they ever got me was catfish. Well this year I put on a 1/16 oz chartreuse road runner with a twister tail and got a couple of specks pretty quick, So I put 3 more on with diferent colors. I found out pretty fast that pink worked very well and also a off white with a sparkling silver tail did a good job with almost no cat fish. Through the 2 weeks I still would tie on something that worked well in years past, but with little luck.
What do you think would be the reason for the change in what the specks like from year to year? I personally like the challenge of figuring out the bite, but it still makes me wonder what goes on it the fishes head.
JC

Higher/lower levels of tannic acid in water, higher/lower levels of salinity, higher/lower water temps, different primary food source available each year? Who knows for sure, but if ya pinpoint exactly why they do what they do, write a book, you would sell millions of copies.

Have to agree 150% with Huntin Slabs.............Extremely good question...
Water is higher this year vs last (almost 2 ft in Crescent alone) in & off St Johns.
Colors changed also - Tantic acid or color more brown stained this year in riiver as
well as lakes related to Johns - Cold fronts, weather conditions completely different
this year vs last 4 yrs (2010 forward ) barametric pressure really made difference this
year vs last 1 tenth off - would cause lock jaw at times. high /low pressure
really has pushed envelope. Problems you are talking about is happening in Kissimmee
chain as well above and below locks West Toho to below River Ranch. Commin up with
answer would or could make you very popular person.

I know last year I had to use a white jig head with whatever color i had this year they wont touch white

Down here a lot of guys are going with off white curly tails and / or cream color
with white heads etc. and i had never used that color down here.............go figure.
Along same lines, last week at Crescent, friday on pre-fish was working Haaw creek,
flippen to bank and back up into water that was dry last year. weighed 7 best fish,
put them on 20 lbs ice and went to bed (12 lbs 3 oz) Saturday when cold front came
in - pressure went high crazy, fish disappeared couldn't find them anywhere in creek.
from 2 - 23 ft deep, gone or wouldn't touch anything, not even live minnows on bobber. I went crazy..... put boat on trailer at 2pm....

The deeper water this year was part of the equation for sure. Maybe this and cooler water temps do change the natural food supply in the water. It just proves once again that the fisherman that is able to adapt to the changing conditions is the one that catches the fish. JC

Last year white head white body was hot. This year chart head chart body. Try a lot of different colors ,heads ( roadrunners, beetle spins,plane ) just when ya think ya got`em figgerd out they make ya start over! that`s the best part of it, the challenge!!

Amen brother, old saying thats why they call it "fishing"

I'm not sure of all the reasons the fish change their minds but I do know one for sure...... AFTER I have changed all my lines to the color that caught fish THEN they change! THEY KNOW. I don't know how but they know! :banghead