The 30 or so professional fishermen who work the Alpine waters of Italy's Lake Como have a good sense for how the lake operates. They know that in April they have to set the top of their nets one arm's length deep to catch whitefish, and that two months later, the nets must go three or even three and half arm's lengths down. They know that a strong summer wind will make their nets travel far and fast but that a winter wind won’t, and they know that when the surface waters of the lake travel north, water deeper down will travel south, and vice versa.
Scientists have recognized the value of local knowledge like this, but as a qualitative, not a quantitative source. Numbers matter to scientists, and local knowledge isn’t recorded systematically. But a new study concludes that, in the case of Lake Como, local knowledge can produce information that matches scientifically collected data and convey some information scientists might have hard time collecting on their own.
“If local people engage in a form of practice (in my case it was their professional fishing practice) that requires an experiential knowledge of certain dimensions of an environment,” says Sarah Laborde, the lead author of the study, “then they will have developed a form of knowledge of that environment that may be combined with scientific inquiry.”
Laborde, a Ph.D. student at the University of Western Australia, began studying the hydrodynamics of Lake Como for practical reasons: the university’s Centre for Water Research had set up monitoring stations there, providing data for her to use in her studies. But when Laborde went to the lake, she realized that the lake had another intriguing feature: a rich culture connected to it.
To explore local knowledge of the lake, Laborde interviewed fishers first about a characteristic she could measure: wave motions showing how the lake’s temperature changed at different depths over the course of the year. The fishermen’s descriptions lined up with official measurements.
The next step was to interview the fishers about gyres and flows that occurred at a scale the university’s instruments weren’t measuring. Based on the fishermen's descriptions, Laborde and her colleagues came up with a hypothesis about why these features developed. When they tested that hypothesis against the data, their results corresponded with the fishermen's descriptions. “Scientists can only record physical properties of environments at certain spatial and temporal scales,” says Laborde. “Often, local knowledge operates at scales that are different to those.” In her study, the fishermen were able to describe processes that “might have been overlooked, had we relied only on the physical data,” she says.
Laborde is not the first researcher to explore how local knowledge might aid scientific goals. Her point is that this type of information needn’t be sequestered in an entirely different column. It’s possible, she argues, to connect cultural, qualitative knowledge with quantitative scientific knowledge.