Greek Fisherman Are Almost As Accurate As Environmental Satellites

Artisanal fishers can be almost as accurate as satellite data when it comes to their awareness of features that can be found in the marine environment, a new study has shown.

Published in the journal Ocean and Coastal Management, the research set out to establish the value of local ecological knowledge (LEK) and its ability to generate high quality habitat maps around five Greek islands in the eastern Aegean Sea.

Ten fishermen, based on their individual experience and knowledge, were asked to pinpoint areas where they believed seagrass beds could be found along the coastlines of their respective islands.

The maps they produced were then compared with satellite data of the same regions, with analysis showing an average accuracy of 78% – and a high of 92%.

The fishermen’s maps were also 11% more accurate than those used by the Greek government in the development of environmental policies, with more than half of the government maps underestimating the scale of seagrass beds found across the region.

The researchers say their findings are a clear demonstration of the value of tapping into local knowledge, and how doing so can be a low-cost means of generating environmental data without compromising the high accuracy needed for the data to be still valuable for policy use.

The study was carried out by researchers from the University of Plymouth and the Archipelagos Institute of Marine Conservation. They worked closely with fishermen on the islands of Fourni, Arki, Patmos, Lipsi and Leros, each of which are home to communities made up largely of small artisanal fishing vessels.

“Some of the fishermen we spoke to had been sailing the same waters every day for more than 60 years,” Konstantis Alexopoulos, Ocean Science and Marine Conservation graduate, now pursuing a PhD with the Scott Polar Research Institute at the University of Cambridge.

“That experience has given them a huge amount of knowledge, but we wanted to test precisely how accurate their empirical data were in comparison to more traditional sources of information. For some personal recollections to be 90% as accurate as the data provided from satellites is really impressive, and something we should be taking into greater account. It also highlights the importance of gathering such information, as there is a huge wealth of data within local fishing communities that is otherwise at risk of being lost as fewer younger people enter the profession in the future.”

Those involved in the research say it is another example of how communities, scientists and decision makers could work in collaboration to meet ambitions set out within the United Nations Sustainable Development Goals.

And despite it being centred around the eastern Aegean Sea, they believe their findings – and the methods used to reach them – will be relevant in other parts of the ocean.

In particular, they say LEK could play a pivotal role in generating greater understanding of deeper marine ecosystems which satellites can’t see and for which there are currently little or no maps available to guide management decisions.

“There is a huge global drive to get more people involved in projects that incorporate elements of citizen science,” Dr. Abigail McQuatters-Gollop, associate professor of Marine Conservation.

“Despite that, expert local ecological knowledge is still being dismissed or discredited by those making decisions about the environment. But just because information hasn’t been generated by expensive technology, it doesn’t make it any less valuable. Using people’s life experiences, gathered from fishing and living in an area over many years, alongside other scientific data can help us develop and implement actions that maintain a healthy global ocean.”

Reference: Alexopoulos K, Grandjean TJ, Miliou A, et al. Is sparse Local Ecological Knowledge accurate enough for policy? A seagrass mapping case study from five Greek islands in the Eastern Aegean Sea. Ocean Coastal Manag. 2025. doi:10.1016/j.ocecoaman.2025.107627.

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