Fishy evolution reported in Nature News 2012 and Proceedings of the Royal Society B 11 July 2012. Each Spring salmon migrate from the ocean into rivers and streams in order to breed. Daily records of numbers of salmon migrating up Auk Creek, Alaska have been kept since 1971. These show that in the 1970s there were two peaks in the numbers within one migration season, but by 2011 there has been a marked decline in the numbers in the later migration. In 1979 some genetic researchers bred a genetic marker into the late migrating fish so they could be distinguished from the early migrating population. A team of scientists in Alaska have used genetic data from migrating salmon collected over 30 years and have shown a significant decrease in the frequency of the gene marker. Ryan Kovach, a population ecologist at the University of Alaska in Fairbanks, claimed: “We show that there has been a genetic shift towards earlier migration timing through what appears to be natural selection against the late-migrating individuals in the population”. Over this same period there has been an increase in the average temperature of the water in the stream by approximately one degree Celsius, and this is believed to have selected against the late migrating fish. The researchers also noted the overall population of salmon has not decreased, and according to Nature News this is “genetic evidence of climate-change adaptation”. The Nature News article is entitled “Pink salmon evolve to migrate earlier in warmer waters”. In their original report in Proceedings of the Royal Society B the research team wrote: “Although microevolution may have allowed this population to successfully track environmental change, it may have come at the cost of a decrease of within-population biocomplexity—the loss of the late run. This is not a surprising result; by definition, directional selection will decrease genetic variation”.
Editorial Comment: We are pleased to see these scientists admit something we have been saying for a long time: natural selection decreases genetic variation, i.e. causes genetic loss. The Alaskan biologists with their evolutionary mindset may call this “microevolution,” but what has happened is actually the opposite of evolution. The Auk Creek salmon are still the same species of salmon, and having warm water act against the gene-marked late arrivers has not made the other salmon change into anything else. Evolution requires new genes to be added to living things, but as these researchers correctly point out, they added a gene marker and natural selection is definitely taking it out. Natural selection is a real process, but it can never produce evolution. Whatever has happened to these salmon, they have not evolved, but they have produced their own kind as Genesis says they were created to do. (Ref. ichthyology, population genetics)
Evidence News 18 July 2012