Once widespread in the coastal and outer continental parts of the Northeast Atlantic, Mediterranean and Black Seas, the Angelshark (Squatina squatina) is now listed as Critically Endangered on the IUCN Red List of Threatened Species. This is a result of several factors including the increase in demersal or bottom fishing these regions, subjecting the species to accidental bycatch. In combination with limiting biological traits, such as being a slow-growing and late-maturing species, this has led to a dramatic decline in Angelshark range in the last century.
Fig.1 Angelshark (Squatina squatina) former range.
The Canary Islands are a unique stronghold for Angelsharks, which are sighted in much greater numbers here than any other region.
Although they are protected under local legislation, much work is needed to ensure their survival and preservation as a species. With a common goal to secure Angelshark survival, a collaborative project was set up in 2014 – Angel Shark Project: Canary Islands (i).
The project is a collaborative initiative led by LIB, Museum Koenig Bonn (Leibniz Institute for the Analysis of Biodivsersity Change), The University of Las Palmas in Gran Canaria (ULPGC), and the Zoological Society of London (ZSL). Along with many research and stakeholder engagement projects across the Canary Islands, there has also been ongoing acoustic tracking research in La Graciosa Marine Reserve, an MPA and the largest Marine Reserve in Spain.
To understand a bit more about the acoustic tracking side of the project, we spoke with Lucy Mead, a PhD student and part of the ZSL research team. Lucy is using a combination of Innovasea acoustic receivers, VR2AR for deeper sites, VR2Tx/VR2W for shallower sites, and implanted V9 and V13 tags for the sharks.
Utilising the precise identification from Innovasea’s acoustic telemetry, Lucy is obtaining essential presence/absence data for specified areas in La Graciosa Marine Reserve. So far, 104 Angelsharks have been tagged, with Lucy commenting:
“Angelsharks are a unique species as they are ‘ray-like’ sharks (dorsoventrally flattened) and ambush predators, usually found resting or hiding in or on benthic sediments – this behaviour makes them really interesting and tricky to study with acoustic telemetry!”
Findings from the acoustic research have highlighted a seasonal pattern in species presence, with high abundance in November. In addition, preliminary data suggest that there are sex differences in seasonal space use, utilisation of deep offshore habitat, and diurnal activity patterns.
Further research into the topic is necessary, with plans for site fidelity research being the next step as well as understanding environmental variability around the site and environmental drivers of movement.
We look forward to new updates from the project as we continue to support their research objective.
(i) Further information on the project can be found on https://angelsharkproject.com/canaryislands/. The project is funded by Shark Conservation Fund, Oceanário de Lisboa, Gobierno de Canarias, Loro Parque Fundación, Save our Seas Foundation, Ocean Tracking Network, WWF Netherlands and Natural Environment Research Council UKRI.
Images Credit: Mike Sealey