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Interview: Protecting The Angel Shark with Deep-Sea Knowledge

Héctor Toledo-Padilla explains how Ocean Census is providing crucial deep-sea data to support protection of this critically endangered species.

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“Angel Sharks act as umbrella species. By safeguarding the crucial habitats for them, we simultaneously protect other species that rely on the same environments.”

Almost from the moment the sun rises on the Island of Tenerife, tourists and locals alike flock to beaches like Playa de Las Teresitas. While some pass their time sunbathing on the beach, others head for the sea. Most are unaware that they are sharing the water with the young of one of the most critically endangered marine animals in the world – Squatina squatina – more commonly known as Angel Shark.

As their name suggests, Angel Shark are sharks, but you would be forgiven for thinking they weren’t. Rather than sporting the sleek, torpedo shape of many other shark species, they have a more flattened appearance, with large pectoral fins. Feeding at night, they bury themselves in the sand, waiting for the opportunity to ambush an unsuspecting crab, fish, or other prey passing by.

“Angelshark used to be found all the way from the north of Europe, into the Mediterranean Sea, and then down North Africa, but due to fishing, especially trawling, and habitat degradation, their populations have massively decreased”, Héctor Toledo-Padilla, Senior Project Officer at the Angel Shark Project: Canary Islands.


Boasting high numbers of sightings, the Canary Islands are regarded as a stronghold for Angel Shark. They are listed on the IUCN Red List of Threatened Species as Critically Endangered, and as In Danger of Extinction on the Spanish Catalogue of Threatened Species (Catálogo Español de Especies Amenazadas) – the highest category possible.

Introduced in 2019, the Spanish Catalogue listing offers the Canary Island populations the highest possible protection. It prohibits disturbing, capturing, killing, trading, or exchanging any Angel Shark species, as well as mandating the protection of Angel Shark habitat. “That means implementing a recovery plan, including measures for conservation and protection applied in critical areas for recovery of the species,” explains Toledo-Padilla.

Data for Decision-Making

Developing a good recovery plan requires a number of things, among which is understanding what types of habitats Angel Sharks are using, where those habitats are, and when they are in use. For the species, “we’ve been trying to understand if they are resident in, for example, one beach, or if they are moving across the coast, or between islands, or all around the Archipelago. Knowing the residence level and the degree of mobility of the Angel Shark is key to implementing appropriate conservation measures,” says Toledo-Padilla.

Alongside residency patterns, Angel Shark Project: Canary Islands has also been looking at other movement patterns, such as the differences between males and females, in relation to factors such as water temperature, time of year, or even time of day. The data to support their work comes from many sources. At La Graciosa Marine Reserve, the second largest Marine Reserve in Europe, some 125 Angel Shark have been tagged with acoustic tags, which, thanks to the fifteen receiver stations that have been installed at different depths, will reveal the movements of the tagged Angel Shark in the reserve. Visual ID tagging, involving attaching colourful markers, is used to study the movement and degree of residence of both adult and juvenile individuals. When these tagged individuals are spotted again, researchers will know if the individuals are staying in one place or moving around. If they are moving, they will know where they came from. Genetic samples help the researchers understand movement within and between the Islands and beyond. Meanwhile, citizen scientist divers, snorkellers, and others report their Angel Shark sightings online, offering an Archipelago-wide picture of their distributions.

Filling in A Deep-Water Gap

Almost all of the data collected so far comes from relatively shallow waters. Nursery areas are located in shallow waters – some less than one meter in depth. Divers typically don’t dive beyond 40 metres. Many dives are much shallower than that. In La Graciosa Marine Reserve, the acoustic receivers go to a depth of 130 metres. Yet, there have been occasional deeper sightings from technical divers, which may go to depths of 100 metres, as well as the Pisces VI Submersible, a privately operated submersible company based in Tenerife.

“We know they are moving from deep waters to shallow waters, but we don’t have much data from the deep. The La Graciosa Marine Reserve project will help with that, but the Ocean Census expedition will open the window even more.”

Alongside searching for new species, the 21-day Macaronesia – Tenerife Submersible and Diver Expedition is also hoping to give the Angel Shark Project: Canary Islands more of those crucial deep-sea data points that can help researchers better understand Angel Shark and the spaces that they use.

Together with the information gathered in shallow water, deep-sea observations will help improve a comprehensive recovery plan. Exactly what measures will be recommended will depend very much on what the data reveals, but could include marine protected areas in shallower and deeper waters, greater consideration for coastal development, and thinking proactively about what fishing activities could take place, where, and when. “Trawling is a major threat to Angel Shark, but [even before the ban] due to the characteristics of the archipelago, it was not very common in the Canary Islands,” explains Toledo-Padilla. If that were to change, “before fishing gears that have a direct impact on Angel Shark extend their use into deep critical areas, we will have the data needed to make informed decisions about the correct measures to apply.”

Although the focus of the Angel Shark Project: Canary Islands is angel sharks, Toledo-Padilla says that any protections implemented will also benefit other marine life, “Angel Sharks act as umbrella species. By safeguarding the crucial habitats for them, we simultaneously protect other species that rely on the same environments.”

The Macaronesia Expedition is part of the Ocean Census mission to find and protect marine life before it’s too late. Scientists who work in the field of ocean species discovery and protection around the world are being urged to sign up to the Ocean Census Science Network.

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