A comparison between north and south Venice Lagoon Fishing Valleys Towards Fishing Valleys future
Ana Laura González Fall Semester 2019 - 2020
IUAV - Università Iuav di Venezia EMU – European Post-master in Urbanism Forms of Knowledge Forms of Rationality Professor Ludovico Centis
Over the centuries, the Venice lagoon has undergone constant morphological transforma�ons; Beyond the natural transforma�ons, the territory has become a project of the man who sought to control the risks that the rivers and the Adria�c Sea represented for the lagoon, and which in turn also sought to create a commercially compe��ve environment. A living territory The brackish water mirrors of 55 thousand hectares separated from the sea and with a great biodiversity, have been enriched with the passing of the years of knowledge of man about it exploita�on. According to Galdino Vianello, fisherman, farmer and owner for 30 years of "Agriturismo Le Manciane" already before the 18th century, in the lagoon, there was an economy based on salt and the cul�va�on of vegetables, it was an open lagoon plan with barene and velme that favored the exchange of water and species with the ocean. Then, the lagoon harbored a dozen species of fish of commercial interest, as well as several crustaceans and edible molluscs. In words of the Canal de Pordelio’s fisherman, Alessandro Novello, who for more than 20 years has carried out this ac�vity professionally; adult fish, or juvenile stage, enter the lagoon in the spring period, invoked by the temperature of the water. That because, as being less deep, heats up before the sea; and in autumn, due to the opposite effect, they return to the s�ll warm waters of the Adria�c. During this summer stay, the fish have greater growth than the similar ones that remained in the sea, due to the abundance of food available in the lagoon. Building a new territory According to the historian Piero Santostefano, member of the cultural associa�on "Tra Mar e Laguna"; At the end of the 18th century, with the fall of the Serenissima, a great transforma�on came in the lagoon, arising from the observa�on of man towards the seasonal migra�ons of fish and taking advantage of the uncertainty of the control of the territory between Napoleon and Austria. Between the years of 1700 and 1800 the delimita�on of the most suitable places for the growth of young fish emerged, causing them to remain in the lagoon even in the fall and winter, to raise them and consume them later when they reached their commercial size (2 years).
Fig 1. Commercial species found in Venice Lagoon and in fishing valleys Sourse: Rosseto Luca, “The Management of Fishery in the Lagoon of Venice”, Padova, 2000. Fisherman interviews from september to november 2019. Cavallitno Trepor�. Venice. Italy
This meant the closure of 8,865 ha of the water surface, translated into 23 fishing valleys, first with s�ck fences, which later became permanent structures such as dikes, crea�on of systems to protect the fish during the winter and mobile locks. On one hand they prevent the fish from leaving and on the other they regulate the exchange of water with the lagoon and in some cases with the freshwater channels to manage their environmental needs, since otherwise the valley, during the summer with evaporation it could reach an excessive salinity for the life of almost all species of fish, while in winter it could freeze and thereby lose the fish.
Fig. 2 – Fig. 3 Sourse: CTR
Fishing Valley - an integrated system As the fishing valley´s owners began to close the area of the valley with pipes, to improve the overall result of fish farming, it was necessary to plant young fish inside the valleys, since the natural scourge, almost completely avoided by the dikes, became insignificant. In addi�on, with the sowing of fish, it was possible to have a much higher density in the valley than the natural one in the lagoon and this made it possible to compensate for losses due to various factors, from bird preda�on, to adverse weather condi�ons, such as cold or heat excessive, so in the 19th century they became an efficient way of growing different species of fish. The ques�on is whether this produc�on system is s�ll efficient for its livelihood since especially in the northern part of the lagoon they are threatened in its produc�on and the tendency is to abandon them. Although the so-called fishing valleys refer to fishing as the main economic ac�vity, according to Galdino Vianello, a fishing valley owner in the northern area of the lagoon, the vegetable cul�va�on has always been the predominant economic ac�vity within from them. Fishing inside fishing valleys was be�er than in the lagoon, but in recent years produc�on has been reduced to 60 kg per hectare
per year, which makes this ac�vity prac�cally only for self-consump�on. To these two ac�vi�es is added the hun�ng that has helped to counter the preda�on of fish by birds, but in more recent �mes has also become an important source of income, due to the great interest of sports hunters for the great number of bird species found in the lagoon, mainly in the central and northern zone of it.
Fig. 4 Sourse: Developed by the author
Fig. 5 Distribu�on of birdlife wealth in the municipality of Venice, expressed as the number of nes�ng species per quadrant
Fig. 6 Distribu�on of birdlife wealth in the municipality of Venice, expressed as the number of winter species per quadrant Sourse: Bon, et-al Atlante ornitológico Venezia. 2013
However, according to the study "The Management of Fishery in the Lagoon of Venice" of the total income of the fishing valleys, 50% comes from the sale of fish and 18% of the hunt, leaving the percentage remaining to other activities such as agriculture and minor fishing. Making reference that fishing is the main activity within the valleys. Then, why the fishing valleys of the North of the lagoon are threatened. No one knows for sure the answer, but there are some hypotheses. Although this system seeks to generate an economic and ecological balance, there are several factors that put this balance at risk, and the system in general; finding that more and more fishing valleys in the northern part of the lagoon are being abandoned, unlike the southern zone, where the trend is towards greater production and the integration of new activities that complement them as sustainable tourism. Mainly on the issue of production, some of the risk factors are related to climate change: extreme temperatures, disappearance of some species within the lagoon, migration of new bird species to the lagoon due to climate change, as an example, the flamingos that arrived just 15 years ago and that put the subsistence of the fish at risk as they eat the crustaceans inside the valleys, which serve as food for the fish, predation by the birds and human predation. Some other risk factors are related to the economic interests of the owners of the valleys, where mainly in the north, according to Vienello, families with other profitable businesses acquire these lands for the only purpose of personal recreation such as sport hunting, so fish production will remain in second plane because the necessary investment is more, compared to the result that can be obtained from fishing. Some other risk factors are related to the competitiveness of the product in a global market: According to Stefania Lazzarini, an employee of the Ittica Center company, specializing in the purchase and distribution of fish for restaurants, located in Cavallino Treporti; there is no market in the north of the lagoon because there is not enough product to sell, besides that more specialized labor is scarce; and since the price depends on the quantity of the product, the prices are not competitive in the global market, reaching up to double those imported from Greece or Turkey. The map below indicates the different fish markets of the Veneto region. According to the “Rapporto Statistico del Veneto 2018� it can be seen that there are six markets, all with sale of local products, but with two exceptions that integrate foreign products. We are talking about the Chioggia market; with more than 9 thousand tons of fish per year and with a mix of sales of imported products, but with mostly local products and the Venice market; with 1,295 tons / year but with products mostly imported from abroad.
The ques�on is obvious, why the Venice market, being that it has two fishing valleys at its two extremes, is not compe��ve in rela�on to local products, since the trend for aquaculture companies in recent years according to the “ Sta�s�cal Rapporto del Veneto 2018 ”is on the rise, finding a balance in the exploita�on of fishing companies that is going down. In a world where people eat more and more farmed fish than wild fish.
Fig. 8 Fish markets in Veneto Sourse : CTR / Rapporto Statistico del Veneto 2018
Fig. 9 Fish farms engaged in primary production pase. Year 2017 Sourse : Rapporto Statistico del Veneto 2018
Towards the future Perhaps the condi�on of these fishing valleys has led them to save themselves from the dangers of overexploita�on, preserving their original character and with it the lagoon landscape that characterizes them; Perhaps these fishing valleys are intended to func�on as guardians of the lagoon species, crea�ng different nuances focused on the sustainability of ecosystems, or what their future is. In addi�on, as a man made territory fishing valleys have treasured a lot of knowledge about the lagoon and its processes to create a safe and controlled territory against the risks of �dal varia�ons in the lagoon and with this they have managed to integrate various ac�vi�es that adapt and develop within them, crea�ng a unique territory within the lagoon of Venice. So, if fishing in the lagoon of Venice is an ac�vity that is gradually losing weight against the global market. The fishing valleys may have to adapt to the new needs of the lagoon to face the risks posed by the uncertainty of climate change in a more controlled way, integra�ng new func�ons into the system, such as storing water from sea level rise , or func�on as systems that clean the water of the lagoon, or serve as sediment and marsh nurseries that help in the problem of erosion. It is necessary to see beyond the func�ons that the fishing valleys have had so far to integrate them to the new needs of the lagoon. This work is an invita�on for the reflec�on of the future of fishing valleys within the territory of the Vene�an Lagoon.
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Trepor�. Venice. Italy
G. Vianello, fisherman, farmer and owner for 30 years of "Agriturismo Le Manciane", personal cummunica�on, October 22th, 2019. Cavallitno Trepor�. Venice. Italy A.Novello, Canal Pordelio’s fisherman, personal cummunica�on, October 25th, 2019. Cavallitno Trepor�.
Venice. Italy