Where do the fish go in the winter? Do they hibernate? Do they bury themselves in the bottom of the rivers and ponds somehow? The fresh waters of Blackstone Valley have two types of fish: warm water and cold water varieties.
During the cold months, warm water varieties such as bass and sunfish slow down and lower their metabolism. They can go for long periods of time without eating, a good thing considering their food supply is extremely limited in the winter months.
Other fish such as the three Ps (pickerel, perch and pike) are still active in cold water. That means they are hungry and will go after bait. This works out well for the ice fisherman, not so well for the pickerel, perch and pike. Trout are the exception: they slow down in winter waters but can still be enticed to go for the bait of fishermen.
There is a scientific explanation. Fish are poikilothermous (cold-blooded); their body temperature follows that of the environment. While they are regulated by nutrition, photoperiod (daily length of light exposure) and water temperature, the reduction of temperature is what causes their metabolisms to slow, some species more than others. In fact, some species actually experience brief superficial freezing or super cooling (without freezing) and remain alive. Fish that are active or semi active in the winter usually seek areas of deeper water where only the top layer freezes into ice.
Come to think of it, one usually sees ice fishermen on ponds and lakes, never on a shallow stream.