by Brian Thomas, M.S., & Phil Gaskill
Have you ever been lost and longed for a map and compass? God designed people in His image so that we can create navigational aids. But what if you were a salmon that had to swim to a precise spot hundreds of miles away—all without a guide? Fortunately, migrating salmon use at least three navigational tools that work in synchrony and demonstrate their marvelous design.
How do these fish find their way to the exact same place of their birth? By the mid-1980s, experiments had shown that salmon detect and remember the unique water chemistry of their origins. Young salmon “have a flexible system for learning olfactory waypoints at appropriate times and places.”1 When heading downstream to the ocean, they record the water chemistry along the way so that they can later retrace their path in reverse.
Salmon use their extremely precise olfactory senses to zoom in on the exact location of their spawning ground, but they first have to navigate to the general area.
In a 1998 experiment, researchers transported hatchery-raised sockeye salmon, some of them blind, several kilometers away from the area of their birth in Japan’s Lake Toya. The sighted fish quickly navigated right back to their place of origin, while the blind fish swam randomly for most of the day. The authors wrote, “It is surprising that the fish identifies his position in open water and the direction of the natal [birth] area with such a high degree of accuracy.”2
So, the second navigational tool—the primary one for salmon—is a polarized light compass. A 2003 study of salmon’s polarized light compass stated, “When the sun is lower on the horizon…the position of the sun can be determined unambiguously by the distribution of polarized light.”3 Exactly how the fish determine the distribution of polarized light, measure its angle, and use that information to navigate is not yet known.
But how would salmon navigate at night or under cloud cover? Like any good engineer, the Lord Jesus designed salmon with redundant technologies. Salmon possess a third navigational tool—a magnetic compass….olfactory, magnetic, Jesus, cloud, engineer, sun, light,
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