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Fighting a Chile mining project with science: Q&A with biologist Maritza Sepúlveda

  • A recently approved mining project on the Chilean coast has sparked concerns from scientists about the potential impacts on the marine mammals living in the nearby Humboldt Archipelago.
  • The channel between the islands and the mainland are home to 15 species of cetaceans, including fin whales, which feed in the area where the mining port will be built — putting them at threat of ship strikes.
  • The mining project was previously rejected by the provincial after scientists raised their concerns; among them was marine biologist Maritza Sepúlveda, who studies the marine mammals of the Humboldt Archipelago.
  • She says the marine reserve that currently covers just three of the eight islands in the archipelago needs to be expanded to cover a much wider area, noting that “animals don’t recognize administrative regions.”

Maritza Sepúlveda grew up in San Felipe, a town far from the ocean in central Chile. Despite this, or perhaps because of it, her curiosity about the ocean began early in her life. She always knew that she would grow up to be a marine biologist like Jacques Cousteau, whom she watched on television every week.

At the start of her second year in university, Sepúlveda embarked on a seven-day boat trip to the island of Rapa Nui, best known for its moai stone heads, to participate in coral research. “I knew how to dive, and the professor needed a diver,” she said. During that time, she learned to count whales along with a group of older students who were building their careers around cetaceans. “That’s where my interest in marine mammals came from,” Sepúlveda said.

Today, Sepúlveda is a marine biologist with a doctorate in ecology, working in the School of Sciences at Chile’s University of Valparaiso. She teaches classes on ecology and marine mammals and also conducts research in the university’s Marine Mammal Ecology Lab.

Marine biologist Maritza Sepúlveda. Image courtesy of Maritza Sepúlveda.

In recent years, Sepúlveda has joined a growing community of scientists making the case to the Chilean government about the importance of protecting the Humboldt Archipelago. The archipelago is considered a priority site for conservation as it contains the Humboldt Penguin National Reserve, an ostensibly protected area. The main threat to the islands, conservationists say, is the controversial Dominga mining project just across the channel on the mainland, which includes the construction of a port in the area.

Mongabay Latam spoke with Maritza Sepúlveda to understand the sheer richness and uniqueness of the marine mammals found here, the nature of the threats they face from the mining project, and why the size of the marine reserve doesn’t reflect the animals’ true range.

Mongabay Latam: What do marine mammals face with the construction of Dominga?

Maritza Sepúlveda: The company claims that the reserve will not be affected because the mega port will be built 37 kilometers [23 miles] to the south, but the issue is that the animals move — they move many kilometers. In 2015, we put transmitters on six fin whales [Balaenoptera physalus], the most abundant species of large cetaceans in the area. We installed them in the reserve, but all the whales, without exception, went to feed along the coastal area where they want to build the mega port. So it doesn’t make sense not to consider that area, because it is all one big combination. There are eight islands that, as a whole, [fit] like a jigsaw puzzle. You can’t only protect two pieces but not put together the puzzle.

Mongabay Latam: What was your goal in tracking those species?

Maritza Sepúlveda: This was a project that focused on supporting sustainable tourism in the area so that the traditional fishers, who are the ones involved in tourism, could predict where the animals were so they can conduct [whale] sightings.

But in reality, the most relevant and most interesting parts were being able to know exactly where the whales are feeding and verifying that the animals stay in the area. According to the literature, fin whales were thought to migrate toward Antarctica, occupying that area [around the Humboldt Archipelago] as a transit area and later continuing south. But of the six animals that we monitored, only one made that journey. The other five stayed in the area the entire time.

Mongabay Latam: For how long?

Maritza Sepúlveda: We put the transmitters on and then crossed our fingers that they would transit for as long as possible. The whale that transmitted [signals] to us for the longest time did so for five months. We put on the transmitters in November 2015 and some animals stayed there until the next year — until May or June — and never left; they spent the whole summer there. That was very relevant in saying that the animals do not necessarily migrate and that the whales are not only there to pass through. Instead, they stay there to feed.

A fin whale (Balaenoptera physalus). Image by Maickol Barrera for IEB.

Mongabay Latam: How do you know that they were feeding?

Maritza Sepúlveda: There are two types of movement that the animals can do: a straight movement and a movement called ARS (area-restricted searching). The latter is a search in a restricted area where the animals make erratic movements around the same point. Linear movement tells us that the animals are traveling. Erratic movement, however, tells us that the animals are looking for something. The possibilities are that they are reproducing or that they are feeding.

Since we know that the summer is not the time when these animals reproduce, and that this area is not a breeding area for them either, we understand that what they are doing is feeding.

In the scientific publication, we also superimposed these ARS areas with the areas with concentrated krill, which has to do with the ocean’s productivity, and what we observed is that there is a match.

The routes are shown in this image. Each color is an animal. On one side are two whales that moved in the open sea, but the majority of the animals moved along the coast, including the place where they hope to build Dominga, so the probability of encountering ships is high.

In that other image, the red denotes the ARS areas where the animals stay for a longer time. Those areas coincide with the zones that have greater concentrations of krill and, consequently, are more productive.

Mongabay Latam: Was this information considered in the baseline of the project?

Maritza Sepúlveda: No, it was not. The project entered environmental evaluation long before that. So they did not have that information in the baseline. When the project was rejected for the first time, I prepared a short document, around four pages long, with the results of that research and sent it to the provincial governor at the time. I don’t know if the information contributed — I hope so — but the governor, whose vote was key in the rejection of the project, said he used scientific arguments and opposed the project for that reason.

I wasn’t the only one. I contributed with this [information] about whales, but there were other institutions that contributed scientific information that served to support the rejection.

Mongabay Latam: Besides collisions with ships, what other threats would the whales be exposed to?

Maritza Sepúlveda: There are direct impacts and indirect impacts. One direct impact is something that hits an animal completely, like a collision with a ship. The animal is either seriously injured or it dies, because we are not talking about small boats. We are talking about big ships.

On the other hand, there are sounds: the noise emissions. It’s as if the whales spend are in a nightclub all the time. Imagine living in a nightclub. How would you communicate with your peers? Communication would be difficult. The animals need sound to be aware of their environment. Now, it’s not that the animal will die from the impact of sound, but there is a cumulative impact. If it’s prolonged over time, it will cause harm to the animal on a medium- or long-term scale in terms of stress, communication problems, and impacts that we haven’t quantified, but that we know exist.

A humpback whale (Megaptera novaeangliae). Image by Guido Pavez.

On the other hand, with respect to the desalination plant that is being planned in the Dominga project, it would take large volumes of water and later return it to the ocean as brine, with a high salt content, and change the area’s physical and chemical conditions. This has consequences for the species, especially for the invertebrates that are at the bottom or in the water column. These species would go under; there are problems with fisheries, but also with the entire food base of marine mammals.

Lastly, the risk of the introduction of polluting elements, like heavy metals or eventually oil, can be very damaging for all the animals.

Mongabay Latam: What’s the conservation state of the fin whale?

Maritza Sepúlveda: It’s facing serious conservation problems. It’s considered vulnerable by the IUCN and endangered under Chilean law.

Mongabay Latam: What accounts for this difference?

Maritza Sepúlveda: The IUCN measures the conservation state of animals on a global scale. But the fin whale is a globe-trotting species. In certain places it doesn’t face so many problems, but it does in Chile.

Mongabay Latam: Why?

Maritza Sepúlveda: This was the most hunted whale of all in the days of whaling. So the populations decreased. Now, in the past few years, there has apparently been a recovery of the populations because we are seeing more whales. But it’s still preliminary and they’re not very abundant. This is why they are considered to be in danger of extinction.

Mongabay Latam: Besides the fin whale, what other mammal species can you find in the area?

Maritza Sepúlveda: Aside from the fin whale, we have two other species that are there: the famous blue whale [Balaenoptera musculus] and the humpback whale [Megaptera novaeangliae].

There is also the bottlenose dolphin [Tursiops truncatus]. This species can be found throughout the world, but in this area, we find the only resident population. These are animals that live here and don’t go anywhere else. Studies have shown the same individual in the area for more than 30 years. In fact, a colleague did a genetic study on these resident dolphins and found that they are genetically distinct from other bottlenose dolphins. Therefore, if you impact this population, you lose genetic diversity.

A bottlenose dolphin (Tursiops truncatus). Image by Guido Pavez.

There are at least 15 species of cetaceans that are found here regularly. We have even seen sperm whales [Physeter macrocephalus].

We also have the famous marine otter [Lontra felina]. It’s one of the marine mammals with the most conservation problems. It’s considered vulnerable, but it’s an animal that’s highly susceptible to impacts because it has a super-reduced distribution area. These are animals that don’t move farther than 4 kilometers [2.5 mi]. They are there and they can’t escape. If there’s an oil spill, they can’t leave. If their food is affected, they can’t leave. Right there, in the marine reserves, we find the highest density of marine otters in the entire northern area. So if you affect this place, you affect an important place for this species that is only found in Chile and in Peru.

There are also two species of seals that cohabit, that is, together on the same rocks. There’s the South American sea lion [Otaria flavescens], which has an important breeding colony there, and the South American fur seal [Arctocephalus australis gracilis], a subspecies from Peru whose southernmost distribution is in the Humboldt Archipelago. For the past three or four years, we’ve been seeing that this place has become a breeding habitat for this species.

In short, it’s an area that’s tremendously diverse in marine mammals that you don’t find in other places in Chile.

South American sea lions (Otaria flavescens). Image by Guido Pavez.

Mongabay Latam: Why weren’t the protected marine areas made bigger from the beginning to reflect the true size of the territory that the species occupy?

Maritza Sepúlveda: When these areas were created, the objective was not the protection of whales, but rather the protection of seabed resources. So they protected 1 nautical mile around the islands. That’s 1.8 kilometers. That — for a whale, for a marine mammal — is nothing. We did studies from the islands looking at the occupation area, and fewer than 20% of the sightings are within the reserve. The vast majority of the whale sightings are outside. So it’s a good measure, but it’s insufficient for these animals, and that’s why we had a meeting last week with the governor, with the mayor, and with other authorities from Atacama to fairly promote a protected marine area for multiple uses.

Mongabay Latam: The Ministry of the Environment also announced this. Is it the same idea?

Maritza Sepúlveda: We don’t know.

A South American fur seal (Arctocephalus australis gracilis). Image by Guido Pavez.

Mongabay Latam: What do you know about the announcement from the Ministry of the Environment?

Maritza Sepúlveda: Not much. We don’t know which spot they’re considering. We don’t know if the coastal area toward the open sea will be protected. We think that most likely it won’t be; the area is designed in such a way that the coast is exposed for the development of activities and so that transit zones are left so that ships can move around. That’s not what we want. We want two things. The first is for the protected area to be continuous, from the coast to the open sea. The second is that the Atacama region be included, because the animals of that region also travel around there. It’s as obvious and simple as saying that animals don’t recognize administrative regions. They have no idea whether they’re in Atacama or in Coquimbo. So you can’t leave out the entire sector that’s part of the archipelago. So that’s our fight: we as scientists are supporting, with all the necessary data, the sustainment of this protected, complete and bi-regional marine area.


Sepúlveda, M., Pérez‐Álvarez, M. J., Santos‐Carvallo, M., Pavez, G., Olavarría, C., Moraga, R., & Zerbini, A. N. (2018). From whaling to whale watching: Identifying fin whale critical foraging habitats off the Chilean coast. Aquatic Conservation: Marine and Freshwater Ecosystems, 28(4), 821-829. doi:10.1002/aqc.2899

Heredia‐Azuaje, H., Niklitschek, E. J., & Sepúlveda, M. (2021). Pinnipeds and salmon farming: Threats, conflicts and challenges to co‐existence after 50 years of industrial growth and expansion. Reviews in Aquaculture. doi:10.1111/raq.12611

Sepúlveda, M., Arismendi, I., Soto, D., Jara, F., & Farias, F. (2013). Escaped farmed salmon and trout in Chile: Incidence, impacts, and the need for an ecosystem view. Aquaculture Environment Interactions, 4(3), 273-283. doi:10.3354/aei00089

Banner image of a blue whale (Balaenoptera musculus) by Guido Pavez.

This story was reported by Mongabay’s Latam team and first published here on our Latam site on Oct. 29, 2021.