Recent acoustic estimates suggest that the mesopelagic zone might harbour 10,000 million metric tonnes of unexploited fish biomass, far exceeding global fisheries catches in the epipelagic zone. This has attracted renewed attention to the utilisation of mesopelagic resources. With the global demand for food projected to increase by 60% by 2050, the sustainable exploitation of mesopelagic resources represents a potential game changer.
The fundamental biological knowledge needed for sustainable resource management and an understanding of the vital role of mesopelagic communities in global processes, e.g. biogeochemical cycling, is however lacking. Therefore, renewed research efforts on this largely unexplored and unexplained ocean realm are timely.
This theme session provides an opportunity to review and report on the extensive ongoing international activities in mesopelagic research. Empiricists, modelers, experimentalists, and theoreticians are invited to present studies, share findings from recent cruises, and exchange ideas on the structure, function, and change of mesopelagic ecosystems and interactions with other ocean realms.
Contributions are invited that relate to the mesopelagic zone and:
- biomass and biodiversity
- life histories and behaviour
- foodweb interactions
- the biological carbon pump and climate regulation
- technological advances to study the ocean twilight zone
Specific examples of interest include:
- the estimation of mesopelagic biomass
- species composition, population structure, and complex biogeography of mesopelagic communities
- drivers of its biomass and interactions with epipelagic and bathypelagic communities
- physiological measurements of vital rates
- studies of life histories and behaviours
- the importance of midwater species in the diet of oceanic top predators and commercial fish stocks
- the fraction of mesopelagic organisms that migrate and controls on their migration
- consequences of deoxygenation for mesopelagic biota
- implications of harvesting midwater organisms.
