Angelshark monitoring by natural markings

The populations of angelfish (Squatina squatina) outside the Canary Islands are regionally extinct or are too small and poorly documented to be used to generate biological information that allows the development of measures that prevent the extinction of the species. To date, there is no systematic monitoring in the Canary Islands to identify population trends.

Squatina squatina
Conservation Status: Category CR (Critical Hazard) on the IUCN Red List.
Wild population: Unknown, in decline.
Captive population: Very few.

Objectives
The general objectives are: 1) Describe the structure of the population. 2) Estimate the minimum population size and relative abundance. 3) Determine apparent survival and re-sighting chances. 4) Increase the scientific knowledge base for effective local population management. 5) Raise awareness about conservation and sustainable use.

Strategies
The natural marks of individuals of S. squatina observed during visual underwater censuses will be used for the individual identification that defines the population structure, and to estimate the minimum population size in Gran Canaria. The structure, variations, and minimum size of the population will be used as an indicator of its biological efficacy. To minimize the impact on individuals and not alter their behaviors when swimming, feeding and mating, or to avoid other impacts in angelsharks that have not yet been evaluated, the study uses a specific non-invasive technique.

Actions
Periodic visual censuses will be carried out in 6 different coastal locations of Gran Canaria by the project team, locating and taking data on S. squatina. The locations will cover an area of ​​approximately 27,000 m2 (180m x 150m), in a depth range of 0-30 m each. The data collection will include: total length, sex, depth, temperature and photographs, emphasizing the natural marks that allow identification. The photos will be analyzed, pointing out the distinctive marks to identify the individuals, and will be classified into subgroups for later comparison.

Gran Canaria

Local Contributor:
ElasmoCan

Funding since 2016: 38,390 $
Squatina squatina

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