AMENAZA ROBOTO | From drought to floods: ROCHA
Quicksand
Artisanal fishermen working in the brackish coastal lagoons of Valizas famously supply premium shrimp, attracting tourism, gastronomy, and commerce. But when an unusual climatic effect interrupted the communication between the ocean and inlets of this ecosystem at an inopportune time, it caused a bumper harvest that turned catastrophic.

This project was supported by The Pulitzer Center.

By: Miguel Ángel Dobrich and Gabriel Farías.
Geospatial data: Natalie Aubet and Nahuel Lamas.
Photos: Matilde Campodónico. Design: Antar Kuri.
Edits: Victoria Melián. Translation: Alexandra Waddell.

September 6th, 2023
Alejandro Álvarez grew up and still lives in the department of Rocha, on the banks of the Valizas Stream, with his children and his wife. He is part of a small community of about ten families who have lived there for decades and whose main income comes from artisanal fishing.

They catch several species that thrive in the stream and in the Castillos Lagoon; one of them—shrimp—makes the difference in the income of the fishing families.
Homes in Puente de Valizas, Rocha department, Uruguay.
Valizas is a shrimp fishery par excellence. The most renowned chefs of the region's leading tourist destinations—such as Punta del Este, José Ignacio, La Pedrera and Punta del Diablo—select the best specimens in Valizas, which they then serve in their restaurants to customers with fat wallets. Since 2015, a shrimp harvest festival called a camaronada has been held there each April, attracting locals and tourists from all over. In the summer season, and during the fishing season, hundreds of people migrate to the town to labor in the harvests. Valizas shrimp is highly prized and in demand.

Climate change is threatening the present and the future of this small community of Rocha fisherfolk—and that of all people and businesses involved in shrimp fishing in Uruguay, right up to the consumer.
Alejandro Álvarez with a shrimp trap.
A natural trap
Every year shrimp hatchlings arrive through the Atlantic from Brazil, passing through the Valizas Stream to then mature in the Castillos Lagoon, 10 km inland. They then migrate again as adults to reproduce in the waters off southern Brazil. Where the stream meets the sea is a sandbar formation called la barra, which opens and closes based on the accumulation of sand at specific times of the year. The dynamics of the sandbar at the mouth of the Valizas Stream allow the shrimp to enter the lagoon and later return to the sea. Human intervention accompanies this natural cycle, which in turn initiates a commercial food supply cycle through the fishing industry. The shrimp harvest in the Valizas area begins at the end of the summer, in March, and lasts until May.
Between 1991 and 1994, fishermen abandoned the use of beach nets in favor of shrimp traps, which increased the catch volume. The practice became more efficient and the physical effort of those working in the streams and lagoons was reduced. Uruguayan law authorizes each fisherman to use a maximum of 10 traps, although some fishermen tend to have up to 40.

Artisanal fishing is a trade that is passed down from father to son. Alejandro is the son and grandson of artisanal fishermen. He does not remember seeing or hearing of anything like what he experienced on February 28, 2023. There are no anecdotes of anything similar in the last three generations. None of the villagers interviewed for this report have memories of anything similar to that untimely and frenetic fishing day.
Uruguay has four coastal lagoons, shallow bodies of brackish water characterized by their connection to the sea: Laguna José Ignacio, Laguna Garzón, Laguna de Rocha and Laguna de Castillos. There you can find marine and freshwater species: white croaker, sole, marine catfish (bagre), black croaker, silverside, freshwater catfish, tararira, shrimp and up to three species of blue crab, with a predominance of Atlantic blue crab.

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The fishing ground: coastal lagoons

This atypical day was the result of an atypical dry season brought to the South American continent by a La Niña event. La Niña is a climatic phenomenon caused by the cooling of the waters of the tropical Pacific that began to manifest itself three years ago. But only in the last few months has the Uruguayan population become aware of its transformative power.

In January 2023, farmers and ranchers from the interior of the country were on television showing cracked land where there would normally be a watercourse. In Montevideo, the capital of Uruguay, the crisis arrived just 60 days later, when the reserves that supply drinking water to almost two million people, more than half of the country's population, reached critical levels. To alleviate the situation, officials went to the extremes of mixing fresh water with water from Río de la Plata, an estuary where the Uruguay River flows into the sea and merges with the saltwater ocean. For the first time in the country's history, the water supply network delivered non-potable water to Uruguayan homes.

In Valizas, the phenomenon manifested itself in decreasing the water level, closing off the connection between the Atlantic Ocean and the Valizas Stream, which then dwindled in size.
Images © 2022 y © 2023 Planet Labs PBC.
The channel that flows through the sandbar was closed off by February 5, as shown in satellite images. By February 28, it was still closed, and the water level of the Valizas Stream was at historic lows. Schools of shrimp were confined to a natural pond, also disconnected from the mainstream course. Any passersby who wanted to could catch them with just a bucket or even a towel.
Shrimp traps are essential pieces of fishing infrastructure.
Pesca previo a la apertura de temporada. Foto: Amenaza Roboto.
From the dawn of February 28th, the news spread among locals, who went to the mouth of the stream in the morning and afternoon. Fearing that the small shrimp would die from a lack of water, fishermen and neighbors sought to catch as many as they could. The shrimp had yet to reach maturity or a decent weight.

The traps that fishermen regularly use for shrimp fishing were ridiculously large for the small amount of water that kept the stream alive. The use of small hand nets and seine nets proved to be more effective.

The artisanal fishermen filled huge, blue 200-liter plastic tubs with the shrimp hatchlings, without having a clear idea of what to do with them or how to keep them in good condition until they were ready for sale or consumption. The most professional refrigeration system they had were household freezers.
The harvest
  • Between 200 and 300 people in the departments of Rocha and Maldonado are involved in fishing and the first stages of shrimp processing.
  • About 200 tons of whole shrimp are obtained. Half of the muscle mass is lost in cleaning: as a result, 100 tons of shrimp pulp enter the local market.
  • Initial sales are worth $1 million USD, and the amount triples with subsequent transactions.

Source: Research data from biologist Santiago Silveira.
To the left is Laguna de Castillos, where the shrimp grow and mature. The lagoon is connected to the Atlantic Ocean (to the right) by the Valizas Stream. The communication between the ocean and the lagoon is regulated by a sandbar that opens and closes.
The largest arrivals of shrimp usually occur in November and December.
As you can see, the Valizas sandbar was open during the postlarvae entry period.
As a result of the drought, the process that would lead to the closure of the sandbar began as the days went by.
During this month, the sandbar closed completely.
The sandbar remained closed during the shrimp growth period.
The lagoon and the creek remained unusually separated from the sea during the period analyzed.
Google Maps and Images © 2022 y © 2023 Planet Labs PBC.
Production imbalance
The alteration in the shrimp harvesting cycle is linked to an overabundance at atypical times that also has its origin in climate change. Biologist and researcher Santiago Silveira, a member of the Atlantic Fisheries Management Unit, explained that the "postlarvae"—the name scientists give to shrimp offspring—benefitted from the increased inflow of oceanic waters of tropical origin caused by the drought. After the opening of the season "there was a lot of fishing for five days," Silveira said.

The 2023 harvest had impressive figures: 1,000 traps were used and 160 tons of shrimp were caught. But as a direct effect of the early—and illegal—fishing, and due to a disregard for the policies that regulate the fishing seasons to ensure the sustainability of the species, the market initially had a large volume of smaller and lighter shrimp. This, in turn, had an impact on the value of the product and on the profit of artisanal fishermen.

That February 28, 2023, the sandbar was closed and remained closed through August 28th, the last date for which our team obtained imagery prior to the publication of this report. By May, when the harvest should have been in full swing, the abundance was over. The president of the Barra de Valizas fishermen's group, Luz Martínez, called it chaos. "It is a moment of total uncertainty; we don't know if the shrimp are finished."

Science is also unaware of a precedent for such a phenomenon in the area. "An event like this year's has never been seen before: Neither our memory nor that of the fishermen has any record of it," said veterinarian and zoologist Graciela Fabiano, a member of the Atlantic Fisheries Management Unit of the National Directorate of Aquatic Resources.

By the end of May, shrimp fishing continued in Castillos Lagoon and Valizas creek, although very few artisanal fishermen were engaged in catching them. There were 60 traps, the catch volume was low and although the remaining shrimp had reached the acceptable size—about 10 grams—to be caught, there was an unexpected incident: An invasive species of ctenophores (an organism similar in appearance to jellyfish) was saturating the nets, preventing harvesting.

According to Alejandro Álvarez, "this shrimp harvest was of no use to anyone. The fishing was a bust because the shrimp came up early and we didn't catch much. I got behind on [bills for] electricity, water, and up to my hands in debt. So imagine the toll this has taken on me."

Climate research by the Department of Atmospheric Sciences of the Faculty of Sciences of the University of the Republic indicates that for Uruguay "changes have already been detected" in some of these climate hazards and that "they will continue and worsen in a context of climate change".

Regarding the dynamics of rainfall and dry days, the research states that "the extremes of precipitation would increase, just as the number of days with light rains would decrease, implying a situation with a greater number of dry days separated by intense precipitation events." In other words, there will be more dry days interrupted by heavy rains.

If extreme weather events continue to intensify, shrimp fishermen will face a failed harvest for the second year in a row.
A hut where fishermen rest and take refuge during long work days.
Luz Martínez, representative of the Puente de Valizas fishermen's group.


The near future
Unfolding changes to shrimp fisheries are an example of the direct influence of climate change on everyday activities, like the preparation of a recipe in the kitchen. Its effects have an impact on critical areas by interrupting the supply chain—and with it the economic equilibrium in a traditionally sustainable productive sector.

Artisanal fishing accounts for 18.4% of the country's total catch, according to data from the Territorio Uruguay Observatory of the Planning and Budget Office. Its destination is mainly for subsistence and supplying local markets.

The continuity of the activity also depends on a scenario that reassures the fishermen who are starting out that their investment in the infrastructure required to work will yield a return within a reasonable period of time. According to research data from biologist Santiago Silveira, new artisanal shrimp fishermen were able to obtain in normal conditions about five thousand dollars of profit per season. "If a fisherman starts from scratch, the operating cost with 10 traps is $250 thousand (Uruguayan pesos)." Traditionally this amount was recovered in two harvests. This was not the case in 2023.
If the drought is prolonged and the coastal bar system remains closed, specialists maintain that there will be no shrimp in 2024. "That would be a very clear effect of the impact of the drought on this fishery," says zoologist Graciela Fabiano.
However, for the second half of 2023, towards spring, large volumes of rain are projected as a result of El Niño, the inverse phenomenon to La Niña, in which warm currents predominate that increase the probability of rainfall in the South American continent. Barra de Valizas fishermen agree that a scenario of heavy rains in spring would be even more devastating for shrimp fishing than the drought. Fisherman Luz Martínez knows that, with large volumes of water, shrimp move from the lagoon and creek to the ocean.

As Fabiano argues, everything depends on the timing of rainfall. If there is a lot of rain, the shrimp will not be able to enter the stream when they migrate to the lagoon. But if heavy rains occur while the shrimp are maturing in the lagoon, the current will carry them away too early.
Artisanal fishing as labor
Researchers, local entities and international organizations such as FAO agree: Artisanal fishing is both powerfully sustainable and highly relevant. In a broad sense, this activity is fundamental for local development because it provides rural populations with livelihoods, generates identity and culture, and transmits this knowledge to society.

Biologist and researcher Martín Laporta maintains that "with a good regulatory framework and good practices, artisanal fishing is an adequate exploitation solution, compatible with the maintenance of ecosystems." Even with a smaller catch, artisanal fishing "is more equitable in its distribution: It generates more jobs than an industrial vessel. For example, with 30 kilos of high quality catch, a small-scale fisherman can employ seven peelers, and his spouse can be in charge of the first point of sale of the shrimp."

In addition, not-so-visible aspects of the infrastructure, such as the monitoring of coastal ecosystems, are linked to fishing activities. Artisanal fishermen are a key element of the scientific community: "From the point of view of research in Uruguay, it would be very difficult to know what we have in our ocean, on our coast, resources and diversity, if there were no fishing."
With special thanks to the Aerospace Remote Sensing Service of the Uruguayan Air Force (SSRA) and to the Technological University of Uruguay (UTEC).
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