Deep Fishing: Dream or Disaster

Abstract

A team of European scientists recently raised concerns regarding the potential of harvesting biomass from mesopelagic ecosystems to help sustain the growing human population. They cite research showing that there may be up to 10 billion metric tons of pelagic biomass comprised of species in numerous taxonomic groups living at depths typically between 300 and 800 m—resources infrequently harvested commercially but with both benefits and risks to being harvested. They stressed the need for sustainable harvests, partly to avoid compromising the needs of future generations. They also stressed the need for further assessment, a more holistic understanding of the dynamics of deep-sea communities, and the need to consider the consequences of such harvests. In this paper, we join this team of scientists in being precautionary—especially in bringing holism to decision making. We take advantage of holistically normative natural patterns for guidance to avoid abnormal consequences of harvesting mesopelagic biomass—consequences involving systems such as other species, marine ecosystems, the marine environment, and the biosphere to include the sustainability of such systems themselves. This involves addressing questions such as “In comparison to other species, would harvesting mesopelagic resources involve abnormality in the depths at which humans harvest from the marine environment?” or “In comparison to other species, would harvesting mesopelagic resources contribute to abnormality in the total harvest currently taken by humans in the marine environment?” We consider other aspects of the human presence and influence on our planet and address observed abnormality as it would be influenced by mesopelagic harvests. Our approach takes advantage of hodepths greater than observed for most conventional fisheries (e.g., Norse et al., 2012; St. John et al., 2016). The mesopelagic zone (roughly 200–1,000 m in depth) is often characterized by a fish community including many species of Myctophiids (lanternfish) as well as other fish and invertebrates— often small-bodied species (e.g., krill, Meganyctiphanes norvegica). The overall complexity with which we are confronted in their evolutionary and ecological interactions is beyond conventional treatment (e.g., see: Merrie et al., 2018); the lack of holism in conventional approaches to management is pervasive. St. John et al. (2016) cite previous work to indicate that there may be as much as 10 billion metric tons of biomass in mesopelagic communities that could potentially be harvested to help guarantee “sustainable development for our growing human population.” Without considering the lack of listic information important to any aspect of management, and especially harvesting resources. This is information about the participation in complex natural systems by other species. We begin by examining the abnormality that would be involved in taking resources at the depths where mesopelagic communities are observed to occur—to directly address the issue of depth. We then consider both directly and indirectly related dimensions of such harvesting to show how abnormality already observed in human participation in ecosystems and the biosphere would be accentuated. We conclude that it would be a serious mistake to harvest deep-sea resources. Harvesting at such depths would itself be an abnormality in the ways humans participate in marine ecosystems. It would also result in the accentuation or perpetuation of many other forms of abnormality—often already extreme in their magnitude. sustainability for the observed human population, these authors are careful to emphasize the need to bring more holism to any decision. We whole-heartedly agree that holism is imperative, particularly when human participation in ecosystems and the biosphere is in question. We also agree that it is extremely important to bring the best available scientific information to the task—something conventional management fails to do (Fowler et al., 2013). With this in mind, we take advantage of holistic normative information (Fowler, 2003, 2009; Fowler et al., 2013) to show that harvesting mesopelagic biomass, at depths where it is found, would be abnormal (and therefore unsustainable) for mammalian species of our body size. This deals with depth directly. As a large-scale environmental impact assessment, we extend this process by bringing holism, and the best available scientific