Pan fish question?

[coreyhkh]

Hey guys I was just wondering how come in some body's of water pan-fish get so big yet in others they are tiny. For example perch on lake Simcoe vs perch in Muskoka lake big difference there in in size.

[Michael_Brown]

There are lots of reasons but generally lakes with big panfish have excellent habitat, food resources and fertile.

Not always the case but some lakes are just better suited to different species.

[tilly]

'cause the big fish always gets away?

[daryl0815]

I have wondered this in the past as well, I think it is mainly to do with what they eat, and habitat, like M.B. said.

 

Same goes for Quinte and Walleyes I guess?

[Roy]

Genetics also plays a part.

[bushart]

I believe their diet is the biggest factor followed by the other reasons.

 

Any fish that has a predominant food source that is Soft sided or fleshed like smelts or ciscoes tend to grow bigger and faster than those that rely on harder sources--like crayfish or hard scaled species.

 

Pretty simple really--easier to digest---cycles faster through their system allowing growth

[l2p]

Might not have anything to do with it but the lake size could also play a factor. I know that some(or maybe all) tank fish grow according to the size of their tank regardless of how much their fed.

[adempsey]

Based on the few research publications that I have read it's primarily related to food source. Although, the size of the lake is often positively correlated with fish size at maturity, this is due to the diversity of food sources available - more energy rich foods (e.g., prey fish compared to mysids) produce larger fish. This goes for all species of fish that include other fish as part of their diet. I think lake trout are a good example of this.

 

Another factor is predation. For species like perch, predation reduces the population density. This in turn reduces competition for food sources and results in a healthier fish population. There is obviously a fine balance here somewhere though.

 

Genetics may also play a role, but I am not sure how distinct fish populations are between various lakes nor do I have any idea how the distribution of fish even occurred. However, it is not uncommon for species that have been physically separated to experience "founder effects" and "genetic drift" - which is basically a reduction in genetic variation within a population. So I am guessing it's possible that some lakes with a small founder population may have a certain genetic variety that is larger at maturity than it's cousins - but typically, the variations in genetics are not ones that are expressed "visibly".