Sustainable science in the deep blue sea

  • Sharks
Years funded
  • 2021
  • Active
Project types
  • Conservation
  • Research

Diana is diving deep into the waters of the Azores to find non-harmful ways to document the diversity and abundance of deep-water sharks. Combining environmental DNA (eDNA) samples taken from depths of as much as 1500 m, with deep-sea baited remote underwater video system (BRUVs) records, she will contrast her findings using these two non-invasive methods with those from the existing demersal longline research fishing surveys. Through this project, she hopes to identify the most sustainable ways to monitor the more than 30 deep-sea sharks and rays caught as bycatch by bottom longline and handline fishing around the Azores.

Sustainable science in the deep blue sea

Diana Catarino

Project leader
About the project leader

For as long as I can remember I have had a passion for nature and its inhabitants, and for the sea in particular. I grew up in a small coastal village close to Sintra in Portugal and spent summer holidays playing at the beach. I was always very curious about all the creatures in the rock pools and would dedicate part of the day to checking what the tide had left on the sand, on the rocks, and in the pools – and I still love doing that today! In my teens, I went on a trip to the Azores,...

Project details

Deep-sea elasmobranchs biodiversity and conservation: Assessment and comparison of non-invasive tools for research and monitoring

Key objective

This project aims to compare the efficiency of two non-invasive methods (eDNA, BRUVs) with deep-sea longlines surveys as biomonitoring tools. We also aim to collect novel knowledge on deep-sea elasmobranchs biodiversity and spatial distribution and identify deep-sea essential habitats and species hot-spots for sustainable management and conservation.

Why is this important

Deep-water elasmobranchs (DWE) are among the most vulnerable fish species known to date with nearly half the species in the North-East Atlantic listed as at risk by IUCN. Despite fishing being prohibited for most species, DWE are caught as bycatch in bottom longline fisheries in the Azores, NE Atlantic. Current monitoring is mostly done by lethal fishing methods. Therefore, alternative non-invasive methodologies are needed for monitoring, without further compromising the conservation of this vulnerable biodiversity.


Many elasmobranchs inhabiting the deep sea live long, reproduce late, and produce few pups. All of these make them particularly vulnerable to anthropogenic pressures such as fishing, habitat degradation, deep-sea mining, and climate change. Knowledge of DWE biodiversity, abundances, essential habitats where key life-history steps occur, spatial ecology and distribution is of great importance for effective and sustainable fisheries management and promote species conservation but is still greatly lacking. Studying DWE is difficult due to their remote habitat, costly to assess, and uncertainties still remaining on the species identification. Furthermore, traditional biomonitoring typically relies on fishing methods which are often lethal. This project will assess the potential of two non-invasive methods, the innovative environmental DNA (eDNA) sampling and Baited Remote Underwater Video (BRUV), in comparison with a fishing survey, to evaluate spatial abundance and biodiversity patterns of DWE in the Azores. The use of eDNA is especially relevant for monitoring vulnerable species such as DWE, overcoming many of the limitations of traditional fishing methods allowing species identification with high accuracy and resolution from water samples. This methodology has proven its efficiency in tracing elusive species, like sharks that were thought to be locally extinct, and it can be a powerful tool in detecting cryptic and rare species. It will be the first time this method will be tested on DWE. BRUVs is also a promising non-invasive alternative that has been widely used to document top predators’ biodiversity, habitat and behaviour, that can allow the detection of cryptic species and to estimate local abundances.

Aims & objectives
  • Compare the efficiency of non-invasive methods (eDNA and BRUVs) in assessing DWE diversity and relative abundances with traditional monitoring techniques (longline fishing).
  • Collect novel knowledge on spatial patterns of DWE biodiversity and relative abundance across the Azores EEZ, and compare them between protected and non-protected areas.
  • Identify areas of deep-sea essential fish habitats and species hotspots for sustainable management and conservation.