Revealed: plan to feed Britain with plankton

Under the scheme, devised by some of the country’s most eminent scientists, the microscopic marine organisms were to be scooped into nets on an industrial scale to fend off starvation.

When the Battle of the Atlantic was at its height and German U-boats were destroying the merchant shipping fleet, the prospect of severe food shortages led to a series of bizarre and top-secret experiments on Scotland’s tidal sea lochs.

Details of the experiments have been uncovered for the first time with the publication of wartime correspondence that involved Sir John Graham Kerr, an MP and regius professor of biology at Glasgow University, and Professor Sir Alister Hardy, another famous naturalist.

Hardy, whose fascination with plankton had been nurtured on a pre-war expedition to the Antarctic, was convinced that the tiny drifting organisms, which are plentiful off the Scottish west coast, could be an important source of protein for humans and animals.

Kerr was also a convert to the idea. In 1941 he wrote to Richard Elmhirst, then director of the Scottish Marine Biological Association based at Millport on the Isle of Cumbrae, suggesting that a plankton-collecting operation should be set up.

“It is of course simply silly to brush the matter aside as of no importance when one remembers the sea off our coasts is often soup-like in its richness with nutritive material over areas of many square miles ... no doubt you have tested for yourself the tastiness of some types of plankton,” Kerr wrote.

Hardy also wrote to Elmhirst in a letter that acknowledged that his plans to stave off wartime hunger were unconventional.

“What do you think of the scheme? Do you think it quite mad? I think it well worth trying,” Hardy wrote.

“Would you come in on a joint venture on it with me? If so we could hatch out a scheme for preliminary trials this summer and put in for an emergency grant.”

The correspondence – much of which was marked “secret” – was discovered by Professor Geoffrey Moore, emeritus professor of the University Marine Biological Station Millport, languishing in an archive at the Scottish Association for Marine Science near Oban.

Speaking to Scotland on Sunday yesterday, Moore said: “Sir Alister Hardy thought it was a way he could contribute to the war effort, because he wasn’t in the forces himself.

“There was plenty of plankton around, but there was the question of how easy it would be to catch. You would need a very large net with a very small mesh. There would be the problem of the pressure of the water trying to push through a net, which would become clogged up with debris – not to mention basking sharks.”

According to the documents, details of which Moore has published in the Archives Of Natural History journal, Hardy calculated that ten nets – each having an opening of 30 square metres – fishing for 12 hours would yield enough plankton to feed 357 people.

One hundred fleets of nets anchored in sea lochs such as Loch Fyne in “sheltered waters comparatively safe from enemy action” would cost £90,000 and catch more than 26 tons of plankton per day. It was envisaged that the strong tides would push the plankton into the nets.

An ingenious suggestion of Hardy’s was that the plankton could be landed in Tarbert or Inverary and dried in bakers’ ovens before being sent off for analysis at Millport.

The proposal was approved by the Agricultural Research Council, who provided a grant, and work began in July 1941. Hardy arrived at Millport, where he was provided with a boat, the Nautilus, and plankton-collecting gear including nets.

By 1942, plankton was being netted at Lamlash, Isle of Arran. But the rich supply of calanus (tiny crustaceans nicknamed water fleas) proved tricky to catch. The plankton settled near the sea bed and there were problems with nets snagging.

There were good hauls in early May and June that year, giving hope that a plankton fishery would be feasible. But the plankton season proved short, and catches diminished as the year went on. The same pattern was observed the following year, and eventually it was conceded that the elaborate organisation and equipment required for a full-scale venture were too costly.

Of course, there was also the thorny question of whether humans, or indeed animals, would be prepared to eat plankton.

Moore, the president of the Society for the History of Natural History, said: “I only know of one person who has tried it, and that was a colleague, Peter Barnett, who was around at the time of the experiments. He found plankton rather fishy and gritty. Unlike a prawn, which you can peel, the exoskeleton was still intact.

“He wasn’t terribly impressed, but I suppose it would depend on how hungry you were.”