Location: The Mediterranean and Caribbean – We can use data from almost anywhere that is > 500m deep
Berths: One, two or none, depending on the crew’s experience with echo sounders
Duration/timing: Ideally a month or more, but shorter periods may be useful
Necessary equipment: Vessel is fitted with an echosounder transducer in the 40 to 10 kHz
Deep scattering layers (DSLs) exist throughout the world’s oceans, reaching depths of around 500 metres. They contain concentrations of commercially valuable fish and crustaceans, and are prey fields for deep-diving predators (king penguins, elephant seals and mantas). DSLs can be detected by echo sounders as they scatter and reflect sound. Only by understanding their variability can scientists predict future changes caused by fishing, rising temperatures or depleting ocean oxygen. The DSLs in the Mediterranean and Caribbean have not yet been studied and are subject to high levels of human exploitation, so knowledge of their deep-water biogeography is important. A link-up between scientists and superyachts with echo sounders will open a valuable window of observation.
If crew members are already trained in the use of echo sounders, no berths would be required. However, having a scientist on board to deal with unexpected instrument crashes would be ideal – two berths for a few days’ training at the start of the voyage when crew members can be shown how to reboot software in the event of crashes would be even better. Data could then be collected without a scientist on board. Yachts need echo sounders capable of logging water column data. The researchers use Simrad EK60 systems and echo sounder deck units can be provided, but yachts must have transducers already installed in the hull. The equipment is compact – about the size of a hi-fi separate – and requires only mains electricity.
This project will make a real contribution to global ocean biogeography and to understanding the structure of the mesopelagic “twilight zone” in the Mediterranean and Caribbean, helping to maintain and improve the health of both. If sufficient data can be gathered, the team will produce a high-impact publication similar to Current Biology, a global biogeography journal that is already extremely influential.
Professor Brierley has been the scientist-in- charge on four scientific voyages and has published 120 peer-reviewed publications.
“Deep scattering layers are fascinating – they’re almost like an outer-space environment. Extraordinary animals hang there in the twilight or total darkness: lantern fish, for example, with their flashing photophores; wonderful crustaceans and giant shrimp. We want to map global variability in terms of depth and intensity and, so far, we have no data from the Mediterranean and the Caribbean. This research will give us a new window into a component of the ocean that we don’t yet have, and it will allow us to understand future change.”