The carrying capacity of the seas and oceans for future sustainable food production: Current scientific knowledge gaps

Abstract

The expected increase in global food demand, as a consequence of a rising and wealthier world population, and an awareness of the limits and drawbacks of modern agriculture, has resulted in a growing attention to the potential of the seas and oceans to produce more food. The capture production of presently exploited marine fish stocks and other species has more or less reached its maximum and can only be slightly improved by better management. This leaves four alternative options open to increase marine food production: (1) manipulating the entire food web structure via removal of high trophic level species to allow an increasing exploitation of low trophic level species, (2) harvesting so far unexploited stocks, such as various fish species from the mesopelagic zone of the ocean or the larger zooplankton species from polar regions, (3) low-trophic mariculture of seaweeds and herbivorous animals, and (4) restoration of impoverished coastal ecosystems or artificially increasing productivity by ecological engineering. In this paper, we discuss these four options and pay attention to missing scientific knowledge needed to assess their sustainability. To assess sustainability, it is a prerequisite to establish robust definitions and assessments of the biological carrying capacity of the systems, but it is also necessary to evaluate broader socio-economic and governance sustainability.

Growth and natural mortality of Maurolicus muelleri and Benthosema glaciale in the Northeast Atlantic Ocean

“…The high mesopelagic biomass estimates (e.g., Irigoien et al, 2014) and potentially large catches make M. muelleri and B. glaciale attractive target species for a commercial fishery; however, high costs and technological challenges have prevented the commencement of a fishery to date (Prellezo, 2019;Grimaldo et al, 2020;Standal and Grimaldo, 2020;Paoletti et al, 2021;Kourantidou and Jin, 2022;Albrektsen et al, 2023). Additionally, gaps in our knowledge remain regarding the global biomass, distribution patterns, and composition of mesopelagic diversity, as well as the function of the mesopelagic community in the marine ecosystem and its importance for ecosystem services (St. John et al, 2016;Hidalgo and Browman, 2019;Wright et al, 2020;van der Meer et al, 2023). The mesopelagic community has a significant role in the sequestration of atmospheric carbon into the deep ocean (Anderson et al, 2019;Buesseler et al, 2022), and exploitation could alter the capture and cycling of carbon (Cavan and Hill, 2022).…”

“…Many mesopelagic species also act as a key resource for higher trophic levels, such as marine mammals (the elephant seal, Mirounga angustirostris, and the common dolphin Delphinus delphis), yellowfin tuna (Thunnus albacares), saithe, and blue whiting (Bergstad, 1991;Potier et al, 2007;Brophy et al, 2009;Naito et al, 2013). To ensure the sustainability of potential mesopelagic exploitation, it is necessary to understand and quantify the population dynamics and resilience of mesopelagic target species such as M. muelleri and B. glaciale, as well as potential subpopulation structures, their trophic links, ecosystem function, and links to biological, physical, and chemical processes and interactions (St. John et al, 2016;Wright et al, 2020;Caiger et al, 2021;van der Meer et al, 2023). An essential step in this process is the estimation of appropriate life-history parameters related to growth and mortality, and their associated uncertainty, for the potential target species.…”

“…Global estimates of the mesopelagic fish biomass are large but remain variable, with estimates ranging between 1 and 15 Gt (Gjösaeter and Kawaguchi, 1980;Irigoien et al, 2014;Anderson et al, 2019;Proud et al, 2019;Hill Cruz et al, 2023). These high biomass estimates have revived interest in the potential exploitation of mesopelagic species, mainly for the production of fish meal, fish oil, and nutraceuticals (Valinassab et al, 2007;FAO, 2011;FAO, 2016;St. John et al, 2016;Prellezo, 2019;Alvheim et al, 2020;Grimaldo et al, 2020;Olsen et al, 2020;Paoletti et al, 2021).…”

“…John et al, 2016;Prellezo, 2019;Alvheim et al, 2020;Grimaldo et al, 2020;Olsen et al, 2020;Paoletti et al, 2021). While the potential for exploitation and the economic viability are already being investigated, the ecological sustainability of a potential mesopelagic fishery remains uncertain (Hidalgo and Browman, 2019;Prellezo, 2019;Paoletti et al, 2021;Dowd et al, 2022;Elsler et al, 2022;Kourantidou and Jin, 2022;van der Meer et al, 2023). Nonetheless, potential management strategies should aim for exploitation according to the stock-specific maximum sustainable yield following a precautionary and ecosystem-based approach (UN, 1982;FAO, 1995;UN, 1995;UN, 2002).…”

Validation of a debiasing addition to Analytical Hieratical Process tools to increase the effects of side-stream utilization and the choice of the filtration system in the European mussel aquaculture and processing industry

“…In addition, one of the main objectives of the new directive is to convert wastewater treatment into a resource center for water, energy, and the recovery of by-products. Securing affordable and sustainable food sources for the rising world population is one of the current challenges that most societies are facing worldwide (Schubel and Thompson, 2019;Costello et al, 2020;Van der Meer, 2020;Farmery et al, 2021;Van der Meer et al, 2023).…”