How can we have fish tomorrow? Ask the past

North Sea Trawler
Dismissed initially as a good storyteller but nothing more, environmental historian Poul Holm has mapped the history of marine animals in such detail that it is having profound impacts on our current understanding of the oceans

When Danish historian Professor Poul Holm began attending fishery conferences his message attracted interest, but also a large slice of scepticism. The fishery scientists thought his ideas made for a good yarn, nice for an after dinner talk, but they cut no ice in the serious business of fishery management.

Holm wanted to talk about historical catch data, and what it implied about the condition of today's fish stocks. But, whilst his ideas won the misty-eyed attention of older marine biologists, keen reminisce about times past, Holm was told that his data were simply too anecdotal to be considered proper science.

'You will never be able to do this in a consistent way that will convince anyone that it is anything but loose ideas,' he was warned.

But Holm proved his critics wrong. In just the last two or three years fishery science heavyweights have begun standing up at conferences and praising his data. Holm’s HMAP (History of Marine Animal Populations) project was seen to have 'shifted the baselines', repositioned scientists' ideas of what an un-fished marine ecosystem might look like.

A decade of history

The HMAP project, a ten year global initiative under the Census of Marine Life, has dug up enough historical evidence to shake our ideas about man and the marine environment.

'The problem with ecosystem theory is that it is established on the basis of ten, fifteen or twenty years of data,' explains Holm, which he says is just not long enough and includes data collected during the boom of industrial fishing. The HMAP researchers aimed to peer much further back into history: 100, 200, or 300 years, to reveal a true picture of the impact of fishing. They collected historical documents such as old ship logbooks, customs books, literary texts, legal documents, tax accounts, ties accounts from the church, private records and even trophy fish photographs. 

What they discovered is helping to rewrite the marine biology textbooks. Logs from 17th and 18th century voyages of discovery, for example, are stacked with evidence of strange encounters with marine species Europeans had never seen before. They tell of abundances of whales in places where there is no evidence of them in living memory, says Holm. Before whales were harpooned in their millions, it appears that large pods of blue whales and killer whales, blue sharks and thresher sharks patrolled the waters off Cornwall and herds of harbour porpoise were then well named for pursuing fish into harbours and up rivers. 

Secrets of the deep

A key find for the HMAP team came early on in the project, when a US historian told Holm about a treasure trove of fishery logbooks dating from the 1850s from the Gulf of Maine.
'We found 3,000 logbooks,' says Holm, 'and no historian had ever touched them before.'

The logbooks were kept by skippers encouraged by special regulations to document fisheries and so collect bounties.
'We were able to establish that the biomass of cod in the 1850s would have been at least 10 times larger than the current recommended conservation level for the entire Scotian Shelf,' Holm explains excitedly. The upshot was that the present conservation goals for this shelf were shown to be far below what these seas once sustained. 

Part of the HMAP project has involved training a new breed of researcher with the talents of a historian crossed with those of a marine biologist. Historians might read logbooks but be oblivious to the biological significance of a sighting of a gray whale in a particular bay; biologists would not know whether the report could be depended upon or was just another tall tale.

Holm had just this kind of experience while studying haddock in the North Sea. It’s just a common species, typical fare for the fish and chips business, says Holm, 'so I was not surprised when, looking through data from German and Danish fishermen in the 18th and 19th century, [that] I was seeing lots of haddock caught off the island of Helgoland in the southern North Sea'.

He recorded the details, but thought little about it until he spoke to Brian MacKenzie, a Canadian fishery scientist at the Technical University of Denmark.
'What?' MacKenzie cried, 'But haddock are never caught in the southern North Sea. They are not endemic there, it’s impossible!'

Eventually the pair realised that once abundant cod populations had simply been fished out. Gone, only to be discovered centuries later in dusty logbooks.

Tuna warning

MacKenzie had a similar experience when looking at bluefin tuna populations. Scientists had previously thought that the species had existed in northern European waters, but he discovered records of sports fishermen catching huge tuna year after year in the straits between Denmark and Sweden.
'We were astonished,' says Holm. 'At first we thought it was a freak event, but it wasn’t. They were all over the place 50 or 60 years ago, but they were fished out and have sort of gone not only from the public imagination but also from the radar of fisheries conservation.'

The pair took the data to the Atlantic tuna commission and argued that the crisis for tuna was much, much worse than thought. 

A long time coming

But one of the most consistent, and revealing, findings from the HMAP project has been the revelation that our seas and islands were depleted much earlier than we might imagine.

When Charles Darwin stepped on to Chatham Island in the Galapagos in September 1835, we all imagine he found pristine seas and an island wilderness. But whalers had hunted there for decades, pursuing quarry that had already been fished out of North American waters, and it took two days hiking for Darwin to find a Galapagos tortoise, a favourite food of seamen. The Beagle too carried some off.

Even simple technology can have a huge impact according to Holm, who notes that the transition from a single hook to several hooks per line in 1850s sent Maine cod populations tumbling.

He also points to Jeremy Jackson’s study of the Caribbean turtle populations. Jackson, the son of a historian and himself a biologist, had been struck by the use of turtle shell in the cupboards, cabinets and inlays in 18th century noble homes and in European museums. Turning to the Blue Books of British Empire, which give trade statistics, he realised that hundreds of thousands of turtles had been caught each year, and that the Caribbean ecosystem had once sustained a population of perhaps 40 million green turtles.
'They were able to wipe out the green turtle population well before industrial fishing technology was introduced,' says Holm, who stresses that there are lots of cases where subsistence fisheries have had a devastating impact.

Consumer choice

'We need to tell the story about fisheries and make people aware and at least give you the choice as a consumer,' Holm argues. The Common Fisheries Policy of the European Union is still driven by economic and social interests, he believes, and has proved disastrous. Holm blames the fact that it is too politicised, a result of compromises that have nothing to do with ecosystems.
'You almost despair when you hear politicians say there is good news: the haddock is gaining some strength or we can increase cod fisheries quota in this area because it has recovered over the last two years. It is such a narrow timeframe and they have no idea how plentiful the oceans use to be.'

Whenever there are traces of a recovery, politicians are jubilant and take measures to drive the population back to the abyss. The solution is to close areas for at least five year period, says Holm, who points to the Second World War as a good example of conservation working – fish stocks were rebuilt in the North Sea, for instance.

Certain industries, such as the tuna industry, need to be tackled and regulated, Holm believes. He looks to the climate change negotiations as offering a possible beacon of hope, believing hey could open up a dialogue which will allow us manage resources that nobody owns and imbue politicians with an interest in issues that may take 50 years to play out, he says. 

Drastic measures

But real action to preserve fish stocks requires something even more dramatic. Holm argues that we should set aside 50 per cent of the oceans as no-take zones, as marine protected areas (MPAs), with industrial fishing in the other half. His views on marine protected areas are echoed by Callum Roberts, author of The Unnatural History of the Sea. He notes that in its closing days, the Bush administration added a number of large marine protected areas in the Pacific and collectively increased the size of such areas by 31 per cent globally:
'That said two things. Number one, the size of the areas wasn't very significant. But two that the global network of MPAs is still very small: it went up from 0.6 per cent to 0.8 per cent of the seas worldwide'.

Roberts’ group at the University of York studied coastal reserves and advised that they need to be 10 to 20 km in diameter and 40 to 80 km apart (though smaller reserves are still valuable). He says fishermen would benefit enormously; in the US, he notes, three-quarters of the haddock caught by the U.S. fishing fleet is captured within 5 km of the boundary of a closed area. Unfortunately, the Common Fisheries Policy has not embraced marine protected areas as a tool to deliver sustainability. Holm says the European Union does not have a proper ocean policy and is too fixated on the industrial use of the oceans.   

When it finishes next year, the History of Marine Animal Populations study might not make for feel-good reading. What it will do, however, is provide an invaluable record of what has been lost, and what we stand to lose if fishing continues along its current course. The option for sustianable ocean management is there; whether politicians are brave enough to take it is another question.

Anthony King is a freelance journalist

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HMAP project

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