A study recently published by the Institute of Ecology and Biodiversity (IEB) and the Millennium Institute on Coastal Socio-Ecology (SECOS) addresses the risks faced by marine habitats in protected areas of Chilean Patagonia, focusing on the factors that have affected forests of macroalgae (Macrocystis pyrifera), a species that is key to the maintenance of coastal ecosystems.

 

Among the main aspects, the study focuses on two as the predominant ones: climate change and the unregulated growth of the salmon farming industry, even within protected areas.

 

Dr. María José Martínez-Harms, author of the study and lead researcher at the Institute of Ecology and Biodiversity, details in this interview the main findings of the publication and also analyzes the current state of protected areas in Chile.

SEGURA: What are macroalgal forests and what is their ecological role?

MARTÍNEZ-HARMS: Macroalgal forests, especially those of Macrocystis pyrifera, which were the focus of our study, are fundamental to the structure and functioning of marine ecosystems in Chilean Patagonia. They are the basis of trophic webs and are often called “ecological engineers,” as they provide three-dimensional habitats that are essential for the reproduction, feeding and shelter of various marine species.

 

They also provide multiple key ecosystem services, such as protecting coasts from extreme weather events, attenuating wave energy, reducing coastal erosion and carbon capture and storage. There is much talk about temperate terrestrial forests because of their role in carbon sequestration and storage, but these underwater forests are ignored even though they also fulfill a similar function, contributing to mitigating climate change by being large “blue carbon” sinks. These underwater forests are important for maintaining water quality, as they function as biological filters, eliminating excess nutrients. They are also key to maintaining the ecological connectivity of seascapes, facilitating the dispersal and reproduction of marine species. In this way, they contribute to the resilience of marine ecosystems, allowing them to retain their ecological integrity despite constant disturbances.

 

In addition to ecosystem services such as carbon sequestration and the provision of essential habitats for marine species, the forests also directly benefit coastal communities.

 

For example, they are key to artisanal fishing, as macroalgal forests act as essential habitats for commercial fish, crustaceans and molluscs. For example, activities such as small-scale aquaculture for the production of mussels (Mytilus chilensis), which is an important economic activity in Patagonia, benefit from the integrity and health of these ecosystems. Many communities depend on these resources for both their economy and their food.

 

Seaweed harvesting is also a traditional practice for several indigenous communities. These algae are used in the food, pharmaceutical and cosmetics industries, thanks to compounds such as alginate.

 

These ecosystems have cultural and educational value, as they are a source of traditional ecological knowledge for indigenous and local communities. Many of these communities have used these algae for generations, integrating them into their culture and traditional ecological knowledge. And they can promote ecotourism and generate economic opportunities through activities such as diving and environmental education.

What are the main threats currently facing these ecosystems in Patagonia?

Our study focused on identifying these threats. Patagonia is often spoken of as a pristine ecosystem, with little human influence. However, even in this region, where around 50% of the land and more than 40% of the sea are “protected” on paper, the threats to the macroalgal forests are considerable.

 

The main one of these is climate change. An increase in the surface and benthic temperature of the sea is expected, which will affect the growth and reproduction of these forests. In addition, events such as marine heatwaves can deteriorate their regenerative capacity and the resilience of these ecosystems.

 

Another critical factor is industrial salmon farming. This economic activity has grown unchecked, even within protected areas such as the Guaitecas National Reserve, the Kawésqar National Reserve and the Magdalena Island National Park. According to regulations, national parks should be exclusively for conservation, but there are currently salmon farming concessions within them. The lack of adequate spatial planning that has allowed salmon farming to develop in protected areas has generated conflicts with conservation in Chilean Patagonia.

 

It has multiple impacts. The installation of pens and farming structures can lead to the loss of marine habitats such as macroalgal forests. This can fragment the landscape, alter the seabed and displace species that depend on these forests for reproduction and food.

 

In addition, the constant presence of boats associated with industrial salmon farming can uproot macroalgae and transport invasive species. Pollution through the use of antibiotics and antiparasitics, which alter water quality and biodiversity. Massive salmon escapes generate competition with native species for food and habitat, altering the trophic structure of marine ecosystems.

 

In addition to these factors, the lack of oversight and regulation has allowed concessions to be granted within protected areas, which exacerbates the situation.

Are there specific regulations to protect them and how has their non-compliance affected them?

There are some regulations, but their enforcement has been insufficient. One of the recent advances is the Benthic Law, passed in January 2024, which establishes regulations for the extraction of algae and strengthens the governance of management areas.

 

Also in 2022, a two-year ban on extraction was decreed in Magallanes to protect Macrocystis pyrifera. However, these measures are not enough. In 2024, more than 230 scientists published a letter in Science urging Latin American governments to protect at least 30% of these ecosystems in their environmental policies.

 

In Chile, the key problem is that, in terms of enforcement, protected areas in Chile are still “paper parks” as they lack monitoring and effective conservation measures.

 

A first step is to stop the granting of new salmon farming concessions within protected areas. It is also important to strengthen the Biodiversity and Protected Areas Service Law (SBAP) to provide protected areas with effective management plans, park rangers and continuous monitoring.  We need marine spatial planning policies to regulate the overlapping uses of the sea, ensuring that activities such as nature tourism are compatible with conservation. Another important issue is to restore the affected macroalgal forests and to demand that salmon companies compensate for the environmental damage they have caused. And finally, it is essential to design conservation strategies that address the cumulative impact of climate change and human activity, to ensure the long-term resilience of these ecosystems.