Fish tagging experiments have been carried out at least since the 1890s, but undoubtedly Ehrenbaum was the first to tag a mackerel. He noted that ‘mackerel are caught from time to time bearing a narrow rubber ring on the fore part of the body, either placed close before or behind the pectoral fins. This perhaps perhaps is nothing more than an an idle jest on the part of the fishermen’. Mackerel, and some other species are caught wearing these rubber rings even now, but in these less naive times we are aware they may more to do with a mariners brief, but amorous trip ashore than they do with any idle jest at sea.
Stephen J Lockwood The Mackerel