Sea Grant offers new publication on using water temperature to find fish
Date: December 22, 1997
FAIRBANKS, Alaska--Finding schools of fish in a really big ocean has always been the fisherman's biggest challenge. To make the job easier, fishers use sonar that show them the contours of the ocean floor and highlight schools of fish. High tech has its place, but some fishermen have discovered that a thermometer may be the best fish finder of all.
Bob Mikol is a commercial fishermen and author of Temperature Directed Fishing, a new manual aimed at helping fishermen reduce bycatch and increase productivity. Fish, like all creatures, prefer a certain climate.
"Fish have certain desired temperatures at which their bodies function most optimally," said Mikol. "Generally one degree will make a significant difference, and certainly two degrees will mean the difference between absolute bareness or bounty."
The manual describes how to find so-called thermal fronts, places where masses of water with sharp temperature differences come together. Until recently, such fronts were rarely used to find fish. But now, fishermen in Norway and Japan are perfecting the tactic, and using it to avoid unwanted fish.
"The evidence suggests that once an area (containing the target species) has been identified, catches of non-target bycatch fish fall off," said Mikol.
Other chapters cover the finer points of plotting and charting temperature variations, the effects of storms on fish behavior and strategies for using temperature to fish effectively.
Kodiak fisherman and vessel owner Al Burch says knowing the water temperature preferred by yellowfin sole helped his dragger-boat captains avoid crab.
"I can't remember what the degrees of temperature were, but it was a very fine line there where we could fish very, very clean or start to pick up crabs," said Burch.
Temperature Directed Fishing is available from the University of Alaska Sea Grant Program. To order, call 907-474-6707. Cost is $4.00. To see other publications and videos, go to the Sea Grant web site at www.uaf.edu/seagrant.
The Alaska Sea Grant College Program is a marine research, education and outreach service headquartered at the University of Alaska Fairbanks, School of Fisheries and Ocean Sciences. It is funded by the National Oceanic and Atmospheric Administration in partnership with the state of Alaska and private industry.
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