The depth and unique characteristics of the Mesopelagic ecosystem (between 200 to 1000 metres depth), which is barely reached by light, have made it essential to combine several innovative technologies to estimate the mesopelagic fish biomass.

The SUMMER project is using 4 different methods that provide data to measure the number of fish:

  • FISHING & Daily Egg Production Method (DEPM)
  • Environmental DNA (eDNA)

Why is the twilight zone so important?

Fish residing in the mesopelagic zone are essential parts of the food chain, providing food for tuna, octopus, squid and many other fish we eat. While the exact magnitude is still unknown, they also play an important role in climate change.

Every night they swim up to the surface to feed and then swim back down, transporting a huge amount of CO2. The mesopelagic zone is therefore the home to the largest animal vertical migration of the world.

It is the biggest, almost unexploited ecosystem on the planet.