Plenty more fish?

Early exploration of the world’s oceans was motivated by the desire to exploit their food resources, to trade, and to assert maritime power. The establishment of the Royal Society in 1660 coincided with improvements in navigation and cartography. Many of its Fellows contributed to these technologies, enabling them to explore the seas and develop their maritime knowledge. In this story, discover how certain major scientific expeditions have contributed to our understanding of marine biodiversity.

He presented drawings of fish to the Royal Society, likely inspired by the work of contemporaries Francis Willughby and John Ray, whose De Historia Piscium (1686) aimed to provide a comprehensive catalogue of fish species from around the world.

The Royal Society forged networks of Fellows within British territories, electing those with position and rank within North American colonies. This supplied information and specimens to satisfy a growing curiosity about the diversity of novel plants and animals.

In 1720, Colonel Francis Nicholson, Governor of South Carolina, granted Mark Catesby permission to ‘observe the rarities of that country for the uses and purposes of the Society'. With this support and financed by wealthy donors, Catesby travelled to North America in 1722, sending back plants, seeds, and other biological specimens for the benefit of his patrons.

Catesby produced the first fully illustrated volumes of the flora and fauna of the region, The Natural History of Carolina, Florida and the Bahama Islands in ten parts between 1731 and 1743. The work featured many fish species, particularly from the Bahamas, and provided valuable reference material at a time when the classification of marine life and the natural world at large was beginning to gain momentum in Europe.

Information on Catesby’s new species was also printed in the Society’s journal, Philosophical Transactions.

The chapter Recherches sur les poissons... (fish research) was a collaborative effort with French zoologist Achille Valenciennes, who had been appointed by George Cuvier to assist Humboldt in the classification of animals from his travels. Valenciennes went on to work with Cuvier on l’Histoire naturelle des poissons (1828), a monumental work consolidating ichthyological knowledge at that time.

Humboldt financed his own expedition, with permission from Charles IV, King of Spain, and he was free to work without limitations. His thinking on the delicate interconnectedness of natural systems, the result of his travels, enabled him to see that humans had the potential to upset them, a prescient view in an era of human-induced climate change.

His observations led him to change his view on the fixity of species and begin to formulate his theory of evolution by natural selection.

Darwin had access to areas of the ocean richest in marine life. He is reported to have collected over 200 species of fish from Cape Verde to Tahiti, the Galapagos Islands and in their largest number, in South America.

On board the Beagle, Darwin carried an extensive library of reference books on marine life, including illustrated titles such as George Cuvier's Regne Animal.

On his return, Darwin oversaw the publication of a volume dedicated to fish as Part 4 of The zoology of the voyage of H.M.S. Beagle, with text written by Leonard Jenyns. Jenyns had originally been offered the role of Beagle’s naturalist but had declined.

During HMS Challenger's journey, John Murray, the expedition naturalist, measured the water temperature and analysed its chemical composition at different heights. The crew also sampled the fauna at the surface and the sea floor, using trawls, dredges and nets. More than 4,700 new species of marine animals were collected.

This interest in life in the deep sea was driven by the chief scientist of the expedition, Scottish zoologist Charles Wyville Thomson. A convinced evolutionist, Thomson thought that the cold stable environment at the bottom of the ocean would preserve 'living fossils', organisms that would have changed very little over time.

Only a few species thought to be extinct were found alive, but the expedition collected many specimens from new species. With its systematic use of stations and repeated observations, the expedition laid the foundation for oceanography. And by sounding such places as the Mariana Trench, the deepest place in the world, it improved our knowledge of that least explored ecosystem, the deep-ocean floor.

Coelacanths had been observed in the fossil record since the 19th century, and it was largely agreed that the species had become extinct in the Late Cretaceous, over 66 million years ago.

The 1938 discovery and identification of a large specimen off the coast of South Africa indicated to scientists the possibility that coelacanths were in fact still alive.

Another dead coelacanth specimen was found in the Comoro Islands in 1952 but in order to establish the habits and biology of the family, zoologists needed to catch a live fish.

In 1968, the Royal Society established a committee dedicated to coordinating the study of coelacanths. The committee quickly concluded that an expedition would be necessary. After a first unsuccessful attempt, scientists collaborated with fishermen in 1972 at Iconi, a town on Grande Comore (Ngazidja).

On 22 March 1972 at 2am, Madi Youssouf Kaar caught a live specimen of coelacanth while fishing off the coast of Iconi using traditional Comorian fishing methods and tools. Scientists had trawled fruitlessly in the same waters. The fish was filmed while still alive and was subsequently photographed.

Following strict protocols, samples of the fish were allocated to scientists across the globe who were able to improve knowledge of the fish's anatomy and habits. The coelacanth expedition demonstrates the importance of international collaboration for science.

The event also exemplifies that much remains to be discovered about life in the world’s seas. The effects of pollution and climate change are felt most acutely by communities who live by utilizing marine resources; but damage to ecosystems and losses in biodiversity diminish science, and us all.