Cecil,
With your ponds, you should be able to run some experiments to prove whether or not fish will grow in the cold.
I contend that bluegill will grow, even in the coldest of winter, as long they have an adequate food supply. While their metabolic rates are much, much slower in colder water, that doesn't mean they won't gain weight. If a bluegill eats half a pound of insects over the winter, it should gain at least an ounce of weight, maybe two ounces. With a slower metabolism rate, it has better food conversion rates than in summer, when its system is running full force.
Yes, fish bite because of reflex reaction, but they also bite because they're hungry. If an ice-fisherman must stick the bait in front of a fish several times before getting a strike, is that really reflex? Or, defense?
Either way, I have seen evidence in ponds and lakes that I manage that, if we feed all winter, the bluegill come out on the other side larger than when we went into winter.
For many, many years, I believed that we just shouldn't feed in cold water. I still believe that for northern ponds. I expected the fish to not gain weight...I also believed that they would actually lose weight...which they did, because I didn't feed them.
As I tried a few different management techniques, it dawned on me that these cultured fish HAD to lose weight if they had no food. But, I justified it anyway because I didn't want to compromise water quality with excess feed.
But, as I watched people catch fish under the ice and then watched the fish behavior on a camera, it dawned on me that those fish would eat. So, we devised a method of feeding fish, bluegill, crappie and bass in particular, where we would "chum" an area under the ice with fathead minnows. We would push a pvc pipe through the hole in the ice and pour fatheads down the pipe and they would swim out in four or five feet of water. Within a few days, game fish began to congregate in that area. That made be believe they were hungry. Catch rates went up and everybody was happy.
Regarding all the studies...here's my thoughts. Each study has a purpose and the conclusions are based on good science and good technique (in theory). Therefore, the data is good. At the same time, I have learned that managing a fishery is figuring out what variables have the greatest influence on that particular body of water and then do what we can to offer a positive influence on those variables.
Studies don't do that.
Studies are set up for a set of criteria, planned out and then the plan is executed and the results are properly documented.
I've read studies until I'm blue in the face. They are good, helpful and promote deeper thought (at least for me).
At the same time, I don't see any studies as "gospel". I get paid for results, not research.
It is easy to make the argument that temperature is absolutely a variable that inhibits growth rates in bluegill (and most all warmwater fish). But, what if we supply an adequate food chain to those fish? Do they still not grow? Do they lose weight? If that's the case, then I'll buy into the concept that temperature is "THE" variable at play. Right now, I don't believe it. Even though the studies suggest it, and I don't do any research to disprove it, my clients are often tickled pink and surprised to see fish with better relative weights, fatter tummies and chunkier-looking bodies going into the spring months than they did in the fall.
I won't dispute the science.
I also won't dispute the fat bluegill each spring.
