AT FIRST GLANCE, a restaurant menu may not look like a scientifically illuminating document. But an ambitious project has been trawling through such records of human fare, along with marine logs and archaeological evidence, to chart the history of sea animals, writes CLAIRE O'CONNELL
“The basic idea is to establish a baseline to evaluate the health of global ocean ecosystems,” says Poul Holm, professor of environmental history at Trinity College Dublin and global chair of the History of Marine Animal Populations (HMAP), which he co-founded in 2000.
The initiative feeds into the Census of Marine Life, due to be published next year, and pulls together around 100 researchers working in 15 oceanic regions.
Using “eclectic” sources of data, including tide records, skippers’ logs, ocean sediments and archaeological specimens, HMAP has been building up a history of marine animals across the centuries.
“Probably the most unusual sources would be the restaurant menus,” says Holm. “They are a very good source of information on how we have been eating our way down the food web. If you look at menus 100 years ago you would see a lot of species that today are endangered, like abalone, which would have been very abundant in American restaurants.”
This week, a conference in Vancouver has been pulling together HMAP findings, and basic outlines are starting to emerge, according to Holm. One is that commercial fisheries have been part of our relationship with the sea for nearly a millennium.
“In northern Europe we have data that go back to the origin of large-scale commercial fisheries, which we now know occurred in the 11th century,” he says. “Archaeological analysis of fishbone remains show quite decisively that there was a big push into the open ocean to try and source the fish, and this was probably as a result of the declining returns of riverine fisheries.”
Within a century, marine fish appeared in the diets of northern Europe and new technologies made their debut, such as decked ships and long-line fishing gear to catch deep-water species, such as ling. “The impact of the development of commercial fisheries was much greater and it happened much before we would normally think,” says Holm.
Humans have since been digging ever deeper into ocean resources, he notes. “But now we seem to be running out of geography. In the last 20 years we have been targeting some of the last remaining pristine waters in the globe, the seas of the south Pacific.”
The historical findings may sound gloom-laden, but they also offer some optimism, says Holm, describing how depleted herring stocks in the North Sea recovered in the 1970s when they were given the chance.
“Although we fished down a lot of species so they are commercially extinct, they are not biologically extinct,” he says. “So there is good hope that if we stand back and give the ecosystem some breathing space, the species will actually rebuild – and we have seen that happen in the past.”
But large marine mammals, such as whales, will need longer. “The historical records of catches, and the genetic analysis, show there would have been hundreds of thousands of individuals way back, but now stocks are counted in hundreds,” says Holm. “And the problem is that the mammals reproduce slowly, so we are probably looking at a century-long programme to rebuild whale stocks.”
Meanwhile, Holm hopes that by taking a long look back at marine animals, HMAP can overcome any short-sightedness and plan forward for conservation.
“We have no sense of the perspective of change in history, we only see of change. But if you look at what we have lost, particularly over the last 200 years, you should certainly feel cause for alarm because the losses have been immense, and some of the damage to the ecosystems happened early on,” he says.