In J.D. Salinger’s Catcher in the Rye, the novel’s troubled anti-hero, Holden Caulfield, gets into a strange discussion with a cab driver in New York City. Wondering what happens to the fish when a large pond in New York’s Central Park freezes over for the winter, the agitated cabbie informs Holden that the fish freeze right along with the pond. When the ice melts, the fish thaw out and go on their way.
Can fish and other aquatic creatures really survive in a state of suspended animation until spring? The surprising answer is yes, sometimes. It is true that some fish can spend the winter frozen in ice and come out swimming once the ice melts. Not all fish get caught in the ice, of course. Ponds and lakes freeze from the top down, meaning that beneath the icy surface there is usually a layer of liquid water where fish swim.
But what about fish that are caught in the ice? It stands to reason that the extreme cold would damage the fish’s tissue, effectively killing it. Like all cells, fish cells contain saline, or salt water. Since salt water has a lower freezing point than pure water, even when encased in ice at thirty-two degrees Fahrenheit, cold-water fish are not technically frozen. Moreover, some fish contain a kind of antifreeze substance that allows them to survive very cold conditions.
Much like bears and other hibernating animals, some ice-bound fish are able to shut down basic bodily functions, slow their metabolism, and enter a dormant state. Cold but not frozen, these fish bide their time until spring, when the ice disappears.