The Nature Pages

~~~~~~~~~~~~~~~at OUTRIDER

	The Mind of the Trout A Cognitive Ecology for Biologists and Anglers by Thomas C. Grubb, Jr. University of Wisconsin Press, 2003.
	Both fisheries biologists and anglers are keenly interested in how trout eat, behave and, most of all, think; but while professional scientists are usually preoccupied with the quantitative data that can support a cognitive theory, anglers are anecdotal by nature and suspicious of any concept that lacks dirt under the nails and the tell-tale smell of fish scales. This rare text brings the two disparate parties together on a common stream of inquiry		While a trout may relearn on a day-to-day basis the food items that are most valuable, it need learn only once the distinctive odor of its home stream. It must no forget that odor, and it need not learn the odor of any other stream.
	A chapter on "Cognitive Maps," for instance, reviews research on the ability of fish to figure out where they are in a body of water by visual or olfactory cues. Experiments with brown trout in Norway, like those on spawning salmon locating their natal site, suggest that the sense of smell plays an important role in their mapping ability. Fish also seem to have an inner compass, able to detect the earth's magnetic field. Sockeye salmon fry in at least one study showed a "genetically fixed preference to face north in a text tank, even at night and even when the tank was covered with black plastic to rule out any navigation by star position."
Search our selection channels between tof new, used and out-of-print books.	For the angler looking to better understand his prey, this book offers many insights but no direct advice. The reader must infer that because trout have sharp senses and an innate fear of predators that stealthy fishing gets the best results. Fish are impressionable creatures who form mental images of the foods they feed on most frequently, causing them to reject baits that don't fit the image, much as young children may reject foods that aren't packaged and presented like the fast foods they eat most often.		Wild-caught rainbow trout were tested singly for their reaction to mealworm pieces allowed to drift by. Increased turbidity had an effect similar to that of decreased light intensity at night; the trout detected only closer prey as the water became more cloudy. At the highest level of turbidity the fish appeared to detect prey only half as far away from themselves...
	"Angling is an important contemplative, intellectual pursuit that occupies the attention of many keen analytical minds," author Thomas Grubb, Jr., explains. His text surveys the most recent published findings of the biologists among them and explains, in language accessible to most anglers, what they think trout are thinking and why.