The Fish That Fixed Bicycle Tires

Coelacanths were known to science only as fossils, a lineage of lobe-finned fish that the record suggested had vanished around the same mass extinction that ended the age of dinosaurs, roughly sixty-five million years ago. In December 1938, a trawler working off the South African coast near East London hauled up a strange, steel-blue fish that a young museum curator, Marjorie Courtenay-Latimer, recognized as unlike anything she had catalogued before.

A living fossil, and the internal organs were already gone by the time anyone realized what it was.

By the time ichthyologist J. L. B. Smith confirmed her suspicion, the fish’s soft internal organs had long since decayed in the tropical heat, lost on a municipal rubbish tip before their scientific value was understood. Palaeontologists had speculated for years about the internal anatomy fossils alone could never reveal. Now the possibility of finally checking those speculations had arrived, and been lost again, within the same season.

Smith spent the following years tirelessly searching for a second specimen, uncertain even of where the fish might actually live: were the waters off East London its natural range, or was the 1938 catch a stray carried far from its true home somewhere else in the Indian Ocean? The French colonial administration eventually offered a standing reward for any fish landed, on condition that specimens be turned over first to the Scientific Institute.

The answer came in 1952, when a second coelacanth was caught in the waters near the Comoro Islands, close enough to Madagascar’s northern coast to settle where the fish had likely been living undisturbed the entire time. Subsequent research on later specimens was carried out in Paris, in Tananarive, and in laboratories at Nosy Be, finally giving scientists living tissue to study rather than fossils and speculation alone.

To the scientific world, the coelacanth was a sensational discovery, a living fossil that rewrote assumptions about evolution. To local fishermen around the Comoros, it was simply kombessa, a fish they already knew perfectly well, caught deep on hand lines set between roughly fifty and a hundred and fifty fathoms.

They did not particularly value it for its flesh, which they considered oily and not especially good eating. What they valued were its unusually heavy, rough scales, prized as an excellent, ready-made abrasive for a distinctly practical modern use: rubbing down the rubber inner tubes of bicycle tyres before patching a puncture, a use entirely unconcerned with the fish’s sixty-five-million-year absence from the scientific record.

Study of the properly preserved specimens confirmed some of the palaeontologists’ older predictions and overturned others. The fish’s gut, for instance, proved to contain a spiral valve, an internal structure that lengthens the time food takes to pass through the intestine, a feature shared with sharks and other ancient fish lineages far removed from Latimeria on the family tree.

Coelacanths are known today to be slow-growing, deep-water fish, giving birth to live young after one of the longest gestation periods recorded in any vertebrate. They remain rare, elusive, and, since 2013, formally recognized as a critically endangered species along the western Indian Ocean coast, a fish whose second act as a scientific marvel has always coexisted quietly with its first, more modest life as somebody’s fishing catch.