Distribution and Abundance of Coastal Elasmobranchs in Tenerife (Canary Islands, NE Atlantic Ocean) with Emphasis on the Bull Ray, Aetomylaeus bovinus

Abstract

The current status of the elasmobranchs’ populations and distribution in the Canary Islands is uncertain. Here we investigate the abundance and distribution patterns of coastal elasmobranchs of Tenerife, with a special attention on the Aetomylaeus bovinus population using a photo-identification methodology. A total of 35 visual surveys were conducted in 5 coastal areas, in which pictures were taken every time an elasmobranch individual was sighted to conduct further biometry analyses. For A. bovinus sightings, pictures were used to identify each individual. Relative abundances and sex-ratios of the elasmobranchs recorded were calculated. The Western Coastline of the island was more diverse, showing 8 species out of the 9-total observed. The photo-identification technique allowed a preliminary estimation of the population size of A. bovinus in El Palmar area with 10 individuals identified and 10 re-sightings over a period of 12 months. This study provides the first relevant information regarding broad distribution, abundance and diversity of coastal elasmobranchs around Tenerife. The study also provides information regarding site fidelity of 3 mature individuals of Aetomylaeus bovinus in the South West area.