By: Barinia Montoya
(Read news in Mongabay)
Update: The National Fisheries Service (Sernapesca) told this newspaper that it will file a complaint with the Superintendency of the Environment and possibly with the Public Prosecutor's Office because it has found a "loss of organic matter in the salmon removal maneuvers". According to him, the dead fish are removed with a pump that sucks them up and then the excess water is returned to the sea. The problem is that the delay in removing the dead salmon caused them to deteriorate, so the water that was returned to the sea after the suction procedure contained organic matter. The contamination caused by the latter could aggravate the situation, say the experts consulted for this article. On March 27th, a harmful algal bloom (HAB), also known as brown tide, appeared in the sea of Chilean Patagonia, specifically in the Comau, Jacaf and Puyuhuapi fjords. This phenomenon is caused by the increase of microalgae in the water that have brown pigments, which turn the water that color during photosynthesis. As a result of this tide, as of April 12, "a total of approximately 5595 tons of dead salmon had been reported, of which 3076 tons correspond to the affected centers in the Los Lagos Region and 2519 tons to those in the Aysén Region," Marcela Lara, deputy director of the National Fishing and Aquaculture Service(Sernapesca), told this newspaper.
Camanchaca S.A., the salmon farming company whose farms have been affected by this phenomenon, estimates losses of US$4.4 million. But what worries the scientific and local community is the harmful impact that the brown tide will generate in a unique ecosystem, such as Patagonia, since with the passing of the days this tide will decant and submerge until it reaches the seabed, experts assure, affecting the species that live there. "These algae can kill all types of fish and corals," says Vreni Häussermann, who for more than 17 years was director of the Huinay Scientific Research Center, located in the Comau Fjord. The scientist points out that although they have not been able to dive and see what is happening underwater, the situation is "very serious" and adds that the protected coastal marine area located inside Comau is being completely impacted.
The origin of the brown tide
The Instituto de Fomento Pesquero (IFOP), the scientific body in charge of generating biological information for the Undersecretary of Fisheries, pointed out that this is a natural event produced mainly by the presence of microalgae, which, depending on their type, require different environmental conditions to generate blooms. These climatic and oceanographic conditions that generate this type of blooms "are recurrent and common in all bodies of water, worldwide", said Salmonchile, an association that groups the main Salmon producing and supplying companies, in a statement published on its web page. The Chilean Society of Marine Sciences, for its part, said that this time the proliferation of microalgae was due to the "unusual rises in water temperature caused by the El Niño phenomenon". However, scientists and experts consulted by this media assure that this is not the only cause and that the salmon industry has an important participation in the appearance of the brown tide.
Marine biologist and oceanographer Tarcizio Antezana, who was coordinator of the Network of European and Latin American Institutions in Marine Sciences and an academic at the University of California, told Mongabay Latam that while it is true that these natural events cannot be predicted and that climate change is undoubtedly generating effects on the marine ecosystem, attributing harmful algal blooms only to these impacts "is imprudent and adventurous". Antezana affirms that "the feces plus the organic matter from the food waste given to the salmon generates eutrophication". In other words, an excess of nutrients accumulates in the water, which exceeds the natural capacity of the biotic communities to consume them. The large amount of nutrients generates this harmful algal bloom (HAB) which, according to the specialist, has "a texture similar to egg white that causes the fish to clog their gills when they breathe and die of asphyxia".
Häussermann adds that when this type of microalgae bloom is generated, it clouds the surface of the water, preventing sunlight from reaching the seabed, affecting the species that need it to live. In addition, these algae "grow and live only a week or maybe a little longer," says the biologist. When they die, they fall to the bottom and are consumed by bacteria that use up oxygen in a phenomenon known as hypoxia. Then, since there is no oxygen in the water, all life in the water dies.
Antezana told Mongabay Latam that the direct relationship between salmon farming, eutrophication processes and harmful algal blooms has been demonstrated in several countries, but that in Chile there is a lack of research on this subject. "There is a level of ignorance that is not commensurate with the profits that the salmon industry reports," says the scientist. However, in 2013, Häussermann discovered, together with a group of scientists, that industrial salmon farming had been impacting the marine ecosystems of the Comau Fjord for at least 10 years.
The background
A recent investigation by Mongabay Latam, which exposed the existence of 416 salmon farming concessions inside marine protected areas in Chile, told how the German-Chilean biologist recorded, between 2003 and 2013, the marine species she observed in that fjord. Between one year and the next, the changes were very gradual, but when in 2013 the scientist compared the photographs she had taken at the beginning of the research, she realized that there was almost nothing left of what she had seen for the first time, 10 years earlier. After analysis, the researchers concluded that all these changes had been caused by the salmon industry due to eutrophication and the consequent loss of biodiversity.
The most catastrophic HAB events ever recorded in Chile occurred in 2016. These produced, on the one hand, the mortality of 40 000 tons of salmon and, on the other, paralyzed shellfish extraction for several months in a large part of the Los Lagos Region, says Italo Masotti Muzzio, director of the School of Marine Biology at the University of Valparaíso. It is estimated that both events generated economic losses of US$800 million. Despite all this background, on this occasion "the precautionary principle has been ignored by the authorities," says Antezana. Scientists agree that it was known that a harmful algal bloom could occur. In recent summers, says Häussermann, the salmon farms have had to inject oxygen into the fjord to compensate for the lack of oxygen. The industry itself acknowledges this in a publication in Aqua magazine , which points out that "for many years now, salmon farmers have been implementing oxygenation systems in the farms in order to avoid fish mortality when oxygen saturation (O2) levels begin to drop below optimum".
Oscar Espinoza, head of IFOP's Center for Harmful Algae Studies, acknowledges that the low oxygen levels recorded in the fjord systems of southern Chile can be attributed to different sources, such as, for example, the entry of seawater with low oxygen concentrations that are trapped inside the fjords, but also "due to oxygen consumption by high densities of organisms in culture". This year, in addition, the salinity of the water has increased , because due to the drought, the influx of fresh water that the fjords receive from the rivers, glaciers and rain has decreased. All these elements would result in a cocktail of conditions that favors the growth of harmful algae, experts say. Biologist Flavia Liberona, executive director of Fundación Terram, adds that a fjord "is a narrow channel where water turnover is slower", so from an ecological point of view, "they are not suitable areas for the development of salmon farming". Mongabay Latam sent questions to the company Camanchaca S.A., but did not receive a response by the time this article went to press. SalmonChile, for its part, assures on its website that although the harmful algal bloom "generates concern, it is important to point out that until today the event has been limited to specific areas". It also adds that a bloom was "expected for the end of summer and beginning of autumn", that this has occurred "on a scale that bears no relation to that of 2016" and that both the public sector and the companies have been able to respond in a coordinated manner to the contingency.
The uncertain future
Harmful algae are still alive on the surface of the water in the Comau Fjord. Sardines, snook larvae, crustaceans, and other animals that filter their food, such as mussels and even phytoplankton, are suffering the effects of the brown tide. "They are all without food because (their habitat) is capitalized by harmful microalgae," Antezana explains. But scientists fear that the worst is yet to come. They refer, on the one hand, to the impacts generated by the irruption of the toxic algae in the fjords and, on the other, to the hypoxia it will generate once the algae die and descend to the seabed. "This seaweed can kill mollusks and crustaceans, such as mussels (Mytilus chilensis) and picorocos(Austromegabalanus psittacus)," says Häussermann. If that happens, local fishermen who make a living from harvesting these species will also be affected.
Italo Masotti, who is also a researcher at the Marine Observation Center for Coastal Environment Risk Studies (COSTA-R) of the University of Valparaíso, points out that in areas of channels and fjords in southern Chile, harmful algal blooms considerably affect the local economy - which depends largely on fishing activity - because the species that survive these events "bioaccumulate the toxin, so they cannot be sold until they eliminate it", says Masotti. Through its website, Sernapesca reported that 95% of the dead salmon have already been removed. *Main image: Removal of dead salmon from the farming centers in Comau Fjord. Photo: Alvaro Vidal