News

Chile’s Algal Blooms Challenges

One of the big recent environmental challenges facing the salmon industry in Chile are the Harmful Algal Blooms (HABs) produced downstream from salmon farms, due to eutrophication of water bodies close to and/or underneath salmon pens. In 2022, a new law compelling fish farmers to remove inorganic waste from the seabed and remediate the impact of organic waste beneath pens was passed in Chile which will come into effect in 2024.

Once considered a seasonal delicacy, salmon is now one of the most widely available chile salmonsuperfoods in western supermarkets. The fatty fish is rich in omega-3 fats, selenium, and several B vitamins, and has been attributed to lowering the risk of illnesses and conditions such as heart attacks and strokes. In Chile, salmon farming has grown to become one of the nation’s top trading exports and the country now produces a quite remarkable 25% of the world’s salmon supply, with more than 1,000 fish farms in operation along the length of the Patagonian coastline. Salmon is Chile’s top export outside of mining and, with double-digit growth, is seen as key to diversifying an economy that has been stuck in slow growth and overly reliant on copper production.

But, all is not well. The Monterey Bay Aquarium’s Seafood Watch program rates wild salmon to be one of the best sustainable seafood options, yet the program also suggests avoiding farmed Atlantic salmon from Chile. In recent years, Chile salmon farming has come under fire due to the overuse of antibiotics and environmental damage to surrounding wild fisheries, and it worth noting that a new US trade rule requires countries to demonstrate that their fishery and aquaculture activities are equivalent in effectiveness to the US Marine Mammal Protection Act or risk losing the permit to export seafood products to the US market (Williams et al. 2016; Bedriñana-Romano et al. 2018).

“The Monterey Bay Aquarium’s Seafood Watch program rates wild salmon to be one of the best sustainable seafood options, yet the program also suggests avoiding farmed Atlantic salmon from Chile”

One of the big recent environmental challenges facing the salmon industry in Chile are the Harmful Algal Blooms (HABs) produced downstream from salmon farms, due to eutrophication of water bodies close to and/or underneath salmon pens. In 2022, a new law compelling fish farmers to remove inorganic waste from the seabed and remediate the impact of organic waste beneath pens was passed in Chile which will come into effect in 2024. The law requires holders of aquaculture concessions to take measures to avoid or reduce the deposit of inorganic and organic waste on the seabed and comes with stiff penalties for non-compliance.

Environmental damage through algal blooms

Eutrophication of water bodies from upstream salmon pens contributes to HABs in Chile. HABs have been reported in Chile for more than 40 years, affecting wild and farmed marine resources and human health (Lembeye 1994; Uribe & Ruiz 2001; Guzmán et al. 2002; Suárez et al. 2003; Iriarte et al. 2005; Sandoval et al. 2018). Blooms of the dinoflagellate Alexandrium catenella in Chile have been reported in the scientific literature since 1972 (Guzmán et al. 1975). An intense bloom was detected in the Aysén Region in 2002, which expanded northward to the Los Lagos Region (42°10’S). Since then, there have been recurring outbreaks of A. catenella (Molinet et al. 2003). Exceptionally intense blooms affected the coastal zone of southern Chile in the austral summers of 2009 and 2016. The first Pseudochattonella cf. verruculosa bloom was detected in 2004, and blooms recurred in 2005, 2009 and 2011 (Mardones et al. 2012; Eckford-Soper & Daugbjerg 2016).

harmful algal blooms

The P. cf. verruculosa blooms of early 2016 were economically devastating for the Chilean salmon farming industry, killing ca. 27 million farmed salmon and trout (39,000 tonnes) (Montes et al. 2018). In February 2017, a massive mortality event (ca. 150,000 smolts) was reported in a shipment of smolts transported to the southern Magallanes Region for seeding at sea, as well as a cargo of salmon travelling from Magallanes to the more northern Los Lagos Region for harvest and processing. The mortalities occurred when the wellboats took seawater from the Golfo de Penas (Aysén Region; Southern Patagonia) and adjacent areas. Several harmful algae were found, including the dinoflagellates Gymnodinium spp., Azadinium spp., and Karenia mikimotoi and the diatoms Skeletonema spp. and Pesudo-nitzschia spp. (Anabalón et al. 2017).

This is the first time that a major A. catenella bloom affected coastal areas of Chiloé Island; it produced a major social upheaval. Many local and national stakeholders raised strong concerns about aquaculture-driven eutrophication and its potential association with the widespread harmful algal blooms (HABs) in 2016. Eutrophication of Patagonian channels and fjords from salmon culture in Chile has been recognized as an environmental risk since the early stages of development of the industry (Soto & Norambuena 2004; Niklitschek et al. 2013).

Algal blooms research required

Most studies in Chile have found localized eutrophication impacts under salmon cages. However, there are no broader analyses that could allow better understanding of the fate of nutrients from salmon farming, especially in deep steep-sided fjords where sediments and particulates do not accumulate under the cages and which under current Chilean regulation are considered excellent sites for salmon culture. However, all the organic and inorganic material has to go somewhere, and although greater circulation could facilitate recycling, organic matter may also be accumulating in the deeper bottom of the fjords beyond the farms. Such impacts are not being examined or monitored. Also, inorganic material (e.g. dissolved inorganic N) may be producing new biomass and entering food webs in the ecosystem, including microalgae.

“Most studies in Chile have found localized eutrophication impacts under salmon cages. However, there are no broader analyses that could allow better understanding of the fate of nutrients from salmon farming”

As emphasized by researchers, there is an obvious need to estimate the carrying capacity of water bodies in Chilean Patagonia before allowing an increase in current farmed salmon production levels in new areas further south (Iriarte et al. 2010; Niklitschek et al. 2013; Soto et al. 2019). To date, none of the scientific efforts to estimate the carrying capacity of water bodies described above have been used by the government or private sector to limit maximum fish biomass per area or water body.

Therefore, considering the limited knowledge of the factors promoting the development and decay of harmful algal blooms in Chile (Sandoval et al. 2018), it is crucial to allocate effort to elucidate the relationship between nutrient availability and ratios and HABs in Chilean Patagonia. So far, there is no scientific evidence that salmon farming is or is not affecting the frequency and extent of HABs in Chile, because of major knowledge gaps and limited monitoring of environmental conditions. For example, there is no regular monitoring of areas without salmon farms that could serve as reference sites during HABs.

New salmon laws in Chile

A law compelling fish farmers to remove inorganic waste from the seabed and remediate the impact of organic waste beneath pens has been passed in Chile and will come into effect in two years’ time. The law requires holders of aquaculture concessions to take measures to avoid or reduce the deposit of inorganic and organic waste on the seabed and comes with stiff penalties for non-compliance. Having verified the existence of inorganic waste at the bottom of the salmon farming site, they must clean it up within a period of six months, without prejudice to the appropriate sanctions. Inorganic waste must be transported and disposed of with the means and in the places authorised by current regulations.

“A law compelling fish farmers to remove inorganic waste from the seabed and remediate the impact of organic waste beneath pens has been passed in Chile and will come into effect in two years’ time. The law requires holders of aquaculture concessions to take measures to avoid or reduce the deposit of inorganic and organic waste on the seabed and comes with stiff penalties for non-compliance”

Furthermore, both a recovery plan and a research plan of the seabed in the farm area, accredited by a certifier, must be submitted to state aquaculture agency Sernapesca. The recovery plan must aim to establish the use of physical, chemical, or biological mechanisms to improve the conditions of the sedimentation area and allow the incorporation of organic matter to the environment to be accelerated. The research plan will focus on the study and development of methods and technologies for the recovery of the seabed, the results of which must be delivered to Sernapesca, in order to improve the recovery plans. If a farm operator commits an infraction with respect to all the above, operations at the site will be suspended for two years. In the event that the offender has not removed the inorganic waste within six months, the sanction will be doubled.

Monitoring options from Chelsea Technologies

LabSTAF

labstaf harmful algal blooms
LabSTAF is the world’s leading instrumentation option for Primary Productivity and Harmful Algal Blooms.

  • Analysis of the biochemistry and ecology of aquatic systems
  • Verification of satellite data
  • Facilitates measurement at scales from mesoscale eddies to oceanic fronts
  • Climate change research and modelling
  • Monitoring of algal bloom development and community structure
  • Ecological monitoring to manage water catchments
  • Identify and mitigate sources affecting water quality in catchments

Sensors

Trilix sensor

  • Trilux sensor monitors 3 parameters in a single, highly sensitive probe
  • Low cost solution for widespread algae monitoring and large scale monitoring programmes
  • Real-time data output in μg/l
  • User configurable sampling frequency from 0.1 Hz to 3 Hz
  • Robust ambient light and turbidity rejection
  • Data display and logging with Hawk and Watchkeeper accessories

Leave a Reply

Your email address will not be published.