Category: Seals

The Unnatural History of the Sea – Callum Roberts

Conservation biologist Callum Roberts has spent years researching the history of the last 1,000 years’ exploitation of the sea by human beings. The result, The Unnatural History of the Sea, is a stunning and detailed illumination of the scale of destruction we have wrought on our oceans. I had been under the impression that the development of industrial-scale fishing capabilities (factory ships, flash freezing, gill nets and the like) in the mid 20th century was what prompted the most egregious overfishing practices. This, however, is an example of baseline creep, in which successive generations look back at the conditions of nature experienced by the previous generation, and mistake them for pristine.

Humans have been harvesting marine life for over 1,000 years, moving from the freshwater ecosystems of Europe’s rivers and lakes after denuding them of all significant fish life through astonishingly aggressive (and familiar-sounding) fishing practices such as stringing nets across the entire width of rivers when fish returned to spawn. Siltation of the rivers caused by deforestation on their banks, and the development of better fishing equipment, also contributed to the move to marine fishing.

Millions of sea turtles and whales used to roam the oceans. To put that in perspective, there are under 15,000 southern right whales alive today (we think they’re recovering well – haha), and approximately 200,000 breeding green sea turtles. Numerous sea turtle rookeries, where the animals return year after year to lay eggs, are now lost to memory, after their breeding populations were completely wiped out during the 16th and 17th century by explorers and settlers in the New World. Entire seal and otter populations were hunted to extinction for their pelts. Hunters and fishermen often took far more than they needed, killing for amusement, squandering the abundance and leaving carcasses to rot or tossing excess fish – already dead – back overboard. After perusing logbooks, letters, diaries and other documents, Roberts remarks that rarely did the explorers, settlers and merchants remark on any aspect of the natural beauty of the creatures they saw on their travels, and if they did it is immediately followed by instructions on how to kill and prepare the animal, and what it tastes like.

Natural marine spectacles such as the sardine run off the Eastern Cape coast of South Africa were once far less remarkable and unusual than we find them today. The migration of herring from the Arctic down to the latitudes of the United Kingdom between May and October each year drew thousands of basking sharks (now we get a news article when four are seen in one day) and other predators, and their spawning left eggs lying on the sea floor in layers up to two metres thick. Roberts says that great white sharks also feasted on this bounty of fish, and mentions that there are too many detailed reports of white sharks up to nine metres long from the 18th and 19th century to discount all of them as false. (The maximum recorded length of a white shark in modern times is approximately six metres.) Today white sharks are seen so rarely in European waters as to create a great fanfare when one of them is spotted.

The point is that the oceans used to support far, far more life and abundance than we are able to conceive of today. Herring used to be so abundant in the seas around Scandinavia that they held up shipping. Pods of dolphins didn’t number in the thousands; they numbered in the hundreds of thousands. Whales were seen in similar numbers, surrounding boats, rubbing against them, and drenching them with spray from their blowholes. Ships navigated towards land by following the sound of countless sea turtles swimming towards the beaches they laid their eggs on.

This is a crushing, shocking book. While reading it I frequently felt myself assailed with despair and regret at how long the over-exploitation of marine resources has been underway, and how much we have lost. Bottom trawling dates back to the 14th century, and already then there were complaints (to Edward III of England, in 1376) about its indiscriminate destructiveness. Scientists visiting newly-discovered (they think) sea mounts have found their once thriving slopes reduced to fields of rubble, littered with discarded trawl nets and other fishing gear debris.

The sections on fishing in the deep sea and on trawling are devastating. Roberts contends that there is no such thing as a sustainable deep sea fishery, as the target species are so long-lived and slow growing (and unknown to science), with unknown population sizes, that there is no sustainable number of fish that can be removed without risking the species’s ability to survive.

Finally, Roberts offers some solutions to arrest the awful, seemingly inevitable slide towards ocean barrens populated only with sea jellies and urchins. The steps Roberts outlines in order to save and recover the world’s fisheries are simple to state, but will be challenging to implement:

1. reduce present fishing capacity (i.e. number of boats, level of sophistication – this is not referring to reducing quotas)
2. eliminate risk-prone decision making (i.e. use science, and act only when you have the facts – don’t use hope or gut feel as a decision making tool)
3. eliminate catch quotas and instead implement controls on the amount of fishing (i.e. how much effort can be expended)
4. require people to keep what they catch
5. require fishers to use gear modified to reduce bycatch
6. ban or restrict the most damaging catching methods (e.g. trawl fishing)
7. implement extensive networks of marine reserves that are off limits to fishing

He advocates the use of Marine Protected Areas (MPAs) – scientists estimate that it is necessary to protect 20-40% of the world’s oceans in order to save fisheries for the future. Strangely, to someone who lives here and doesn’t think much of our collective will and ability to police MPAs, especially when fishing is allowed in many of them, South Africa is actually a world leader and has protected a larger proportion of her territorial ocean than many other countries (the world total is about 1.2% of the oceans, with only 0.01% of the world’s oceans designated “no take” zones, according to Wikipedia). The benefits however, even of poorly policed marine parks, are significant.

I am not sure I share Roberts’s optimism that the situation can be reversed or arrested – passages from this book come to me at odd moments, leaving me nauseated at the greed, waste and ignorance that we have displayed as a species, against the life of the sea.

There’s an interview with Roberts that I found interesting, and reviews at American Scientist and the Washington Post.

You can get a copy of the book here or here, otherwise here if you’re in South Africa.

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