A post at www.pasthorizonspr.com/index.php/archives/03/2013/fish-based-diets-cause… … describes how fish can cause problems with C14 dating methodology, even in pottery where fish have been cooked – and presumably in the bones of humans that ate a lot of fish. The discovery of the anomaly came from Denmark and attempts to date material from the Ertobolle culture people, who had a marine based diet. As a result of the Danish research we have what is known as the reservoir effect. The age of the fish come from the river it swims in which has old C14, whereas a terrestrial animal, such as a rabbit, does not (and these too are cooked in pots). Experiments on fish in Denmark showed a discrepancy of between 500 and 2000+ years. In effect, some of the fish swimming in a river in Denmark could theoretically come up with a date up to 2000 years of age – which means people eating fish diets can also give anomalous dates.
Even charcoal from camp fires is now recognised as having a wide range of dates as the people could have burnt branches laying on the woodland floor, or the burnt sample could be wood that was already of great age. This is all a bit convenient for the anomalous dating at Nineveh – where C14 dates come out roughly 150 years too old (from I think human bones, but possibly other material). The anomaly, it seems, has been compartmentalised by the powers that be, as they have decided the people must have been eating a diet high in river fish (presumably from the Tigris or one of its tributaries). We can imagine mainstream will make sure it remains buried and the fish diet will warp into the accepted mantra – without any research to back it up. That is the way of it I suppose. The consensus is defended – and C14 anomalies have to be explained away somehow.