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’ll contrast her findings using these two non-invasive methods with those of 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 caught as bycatch by bottom longline and handline fishing around the Azores.
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,...
This project aims to compare the efficiency of two non-invasive methods (eDNA and BRUVs) with deep-sea longline surveys as bio-monitoring tools. We also aim to collect novel information about the biodiversity and spatial distribution of deep-sea elasmobranchs and to identify essential habitats and species hotspots for the sustainable management and conservation of deep-sea fish.
Deep-water elasmobranchs are among the most vulnerable fish species known to date, with nearly half the species in the north-eastern Atlantic listed as at risk by the IUCN. Although fishing for most of the species is prohibited, these elasmobranchs are taken as by-catch in bottom longline fisheries in the Azores. Because current monitoring is carried out mostly by lethal fishing methods, we need to find alternative, non-invasive methods without further compromising the conservation of these vulnerable species.
Many elasmobranchs inhabiting the depths of the ocean live long, reproduce late and produce few pups. All these life-history strategies make them particularly vulnerable to anthropogenic pressures such as fishing, habitat degradation, deep-sea mining and climate change. Knowing the biodiversity of deep-water elasmobranchs, how abundant they are, the habitats that are essential for key stages in their life history, and their spatial ecology and distribution is very important for managing the fishery of these species effectively and sustainably and promoting their conservation. But too little is known. Studying deep-water elasmobranchs is difficult due to their remote habitat and the cost involved and because there is still uncertainty about species identification. Furthermore, traditional bio-monitoring typically relies on fishing methods that are often lethal. To evaluate spatial abundance and biodiversity patterns of deep-water elasmobranchs in the Azores, this project will assess the potential of two non-invasive methods, the innovative environmental DNA (eDNA) sampling and Baited Remote Underwater Video (BRUV), and compare them with a fishing survey. The use of eDNA is especially relevant for monitoring vulnerable species such as deep-water elasmobranchs, as it overcomes many of the limitations of traditional fishing methods and enables species to be identified with high accuracy and resolution from water samples. This methodology has proven its efficiency in tracing elusive species, such as 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 deep-water elasmobranchs. BRUVs is also a promising non-invasive alternative that has been widely used to document the biodiversity, habitat and behaviour of top predators, to detect cryptic species and to estimate local abundances.
Outside the USA, The Bahamas is the only place where Critically Endangered smalltooth sawfish can reliably be found. Tristan wants to ensure that protection measures in The Bahamas are understood and enforced as far as sawfish are concerned to close the current gap between policy and the people. He’ll be using aerial surveys, sonar and BRUVs, combined with interviews that draw on local knowledge, to identify essential sawfish habitats that need protection. Engaging with the community through workshops and by training students and meeting with government, Tristan intends to advocate for smalltooth sawfish protection throughout The Bahamas’ territorial waters.
Steven and Kevin are using genetic techniques to understand how Caribbean reef shark populations are connected across the extent of their range. Populations of this Endangered shark are in decline generally, but where they are managed and there is effective protection, their numbers are stable. With the integration of the correct information, Steven and Kevin are convinced that we can give Caribbean reef sharks a better shot at recovery and population stabilisation. They will also explore any barriers to connectivity, looking to the future recruitment and recovery of these sharks.
With very little information available about Endangered sicklefin devil rays, their seasonal aggregations at sea mounts in the Azores give Sophie an opportunity to learn more about their lives. She will be collecting satellite-tracking data that show how they move in the Azores’ exclusive economic zone. The information she collects will be used to develop maps of how the rays are using the zone and to identify essential areas that multiple species use. With this information at hand, Sophie hopes her work can contribute to a network of marine protected areas.