The Gallo-Roman writer Ausonius wrote of the Moselle River in late fourth-century Gall as “bright as water in crystal goblets,” and noted that his “vision, when it pierces this stream, finds the open secrets of the bottom.” At this time the main species that people fished for thrived in rivers with such conditions – particularly fishes that migrated between rivers and the sea. Throughout Europe runs of salmon, shad and whitefish numbering hundreds of thousands of individuals would return to rivers to spawn. Vast numbers of eels moved in the opposite direction toward marine spawning grounds in the mid-Atlantic. Giant sturgeon migrated into estuaries and the lower courses of rivers to breed. In the first century, Pliny the Elder describes sturgeon from the River Padus as a fish that “sometimes reaches almost half a ton (450 kilograms) and is dragged from the water only by teams of oxen. All of these species were targets for fishers, who caught them using nets, spears, basket traps, weirs (low dams built across rivers), and hook and line.

This quote is from Professor Callum Roberts’ book, The Unnatural History of the Sea: The Past and Future of Humanity and Fishing. I love this book. It is an account of the marine world documented before the industrial rise of human population growth and development. It talks about how things were. How nature looked. Then of course, the flip side. What happened to it afterwards.

The above passage is from the second chapter, The Origins of Intensive Fishing. Roberts describes the change in the UK and Europe from being freshwater fishers to the transition of reaping the marine environment. It happened around the 10th century AD in Northern Europe.

How do we know? Roberts explains that, before the 10th century, archaeologists have largely found the bones of freshwater fish left behind as proof of long-ago meals. Then after the 10th century, marine fish began to figure in people’s diets. Cod bones from a 3-foot long cod were discovered under the centre of York – for the first time. After this dating event, marine fish bones began to regularly appear in archaeological remains.

The reason that Northern Europeans moved from eating freshwater species to taking marine fish is a tale as old as time. Even if we didn’t know about this shift in our ancestor’s diets, we know all about its instincts.

The development of industry and pollution, changing river courses for the widespread building of water-powered mills at the turn of this first millennial decade, meant fish numbers began to decline.

The number of corn mills rose from 200 in England during the time of Alfred the Great (~ AD 800) to the 5,624 recorded in the Domesday Book of 1086. Crazy or what!

Freshwater fishes became less and less bountiful. People began to look elsewhere for their catch. Until this point, the sea had been left largely untouched. People hadn’t needed the sea for food. This was about to change.

Still, that’s not the bit that I’m stuck on. Just before the quote above describing Europe as a garden of Eden, came Roberts’ explanation of a massive drop in the human population.

Plague devastated Europe. From an estimated 35 million people in 200 BC, numbers fell to around 18 million in AD 650. Almost half of Europe died. Whoa. I’m not suggesting we repeat this pandemic of pandemics. Just remembering nature does well when we’re not around.

https://islandpress.org/books/unnatural-history-sea