It is possible that in the early stages of Chiusi’s, Cortona’s, and Perugia’s presence in the area, they competed for the natural aquatic resources of the Lake, such as fish and reeds. However, competition can lead to over-extraction, which can lead to the degradation the Lake’s already limited resources. All three of the cities would feel the repercussions of the resource depletion, and they may have been persuaded by this fear to come to an agreement regarding the use of Lake Trasimeno (there have been multiple sanctuaries found around the the Lake, indicating that it may have been sacred space which may have played a part in the negotiations). However, after researching the structure of shared aquatic resources of the present day, such as the Yellow Sea, East China Sea and Lake Titicaca, in Peru, I’ve managed to piece together an anthropological parallel of why Chiusi, Cortona, and Perugia decided to share Lake Trasimeno.
During my research, I came across a similar situation to that of Lake Trasimeno in the twentieth century with the Yellow Sea and East China Sea. The China Seas have been used by China, Japan, and both North and South Korea for centuries, however the competition between the nations caused over-fishing, which depleted stocks and posed a threat to the already fragile aquatic ecosystem (Xue 2005, 365). This resulted in the Sino-Japanese Agreement being signed between China and Japan, and the Sino-Korean Agreement being signed between China and the Republic of Korea, in order to manage aquatic boundaries and maintain the ecosystem they all relied on. (Xue 2005, 366).
If this over-extraction situation were to have taken place with Lake Trasimeno, then it is likely that Chiusi, Cortona, and Perugia would have decided to come to an agreement regarding sharing the Lake instead of completely depleting it. This idea is a global phenomenon that Göran Dave and Mohiudan Munawar comment on by saying that “as the degradation of the environment became readily apparent, political will to stop degradation lead to the formation of new national and international agreements to reduce pollution” (Dave et al. 2014, 440). Therefore, theoretically, the three cities could have either come to a formal or informal agreement. They could have come to a formal, written agreement like the China Seas, or they may have come to an informal one like Lake Titicaca, in Peru. The 151 fishing communities around Lake Titicaca have certain “exclusive, though informal, rights,” meaning that the communities recognize the others’ territories without a written record of boundaries (Levieil et al. 1990, 367).
Although the real reasoning behind the sharing of Lake Trasimeno may be lost to us, or simply undiscovered, the idea of over-exploitation is simply one of potentially many theories. Chiusi, Cortona, and Perugia may have decided to develop either a formal or informal agreement over the Lake, or they may have constantly fought over it for generations. This anthropological parallel simply poses one possible situation that the three cities may have found themselves in, which would have called for negotiations over the Lake to take place.
Dave, Göran and Mohiuddin Munawar. 2014. “Aquatic Ecosystems Across Boundaries: Significance of International Agreements and Cooperation.” Aquatic ecosystem Health and Management 17 (4): 437-46. doi: 10.1080/14634988.2014.978245.
East China Sea. From FreeWorldMaps.net. http://www.freeworldmaps.net/ocean/eastchinasea/.
Lago Trasimeno. From Smore.com. https://www.smore.com/wa9f-mosaics-with-karla-duterloo.
Levieil, Dominique P. and Benjamin Orlove. 1990. “Local Control of Aquatic Resources: Community and Ecology in Lake Titicaca, Peru.” American Anthropologist 92 (2): 362-82. http://www.jstor.org/stable/680150.
Map of Copacabana & Lake Titicaca. From Lonely Planet. http://www.lonelyplanet.com/maps/south-america/bolivia/copacabana-and-lake-titicaca/.
Xue, Guifang (Julia). 2005. “Bilateral Fisheries Agreements for the Cooperative Management of the Shared Resources of the China Seas: A Note.” Ocean Development and International Law 36: 363-74. doi: 10.1080/00908320500308767.