A nautical research ship is on an essential mission off the coast of Norway. A group of researchers on the ship is waiting with bated breath as a massive steel wire with a fine-mesh seine net at the tip is rolled out. The trawl net is dropped further and deeper into the water with each revolution until the wire fully expands and reaches its target anywhere between 200 and 1,000 meters beneath the surface in what is referred to as the mesopelagic twilight zone.
It sifts the ocean for live species like a giant fishing net in pursuit of knowledge about an area of the planet that people know much less about than outer space. This deep-water fishing trip in the North Atlantic is part of a research study supported by the European Commission. The project's goal is to see if the fisheries sector can focus on some of the thousands of species prevalent in the mesopelagic zone without recreating the many tragedies that have occurred in the past: bad management leading to overfishing, ecosystem degradation, and biodiversity collapse.
Professor J. Rasmus Nielsen of the National Institute of Aquatic Resources at DTU Aqua is one of the project researchers seeking solutions, and he and his colleagues analyze some of the data acquired by the marine research vessels, as stated by DTU's official press statement.
Massive Quantity of Biomass
These DTU Aqua researchers' study focuses on two tiny fish species, the glacier lantern fish and Mueller's pearl side, which appeal to the industrial fishing sector because of their high oil levels of 20 to 30%. Several species have the potential to be employed in the production of fish oil, fish, medication, as well as a source of food.
As per J. Rasmus Nielsen, they know "absolutely nothing," about the effects of trawling for these species on the food chain or the function they play in the broader environment. He has spent his whole professional life researching, advising, and teaching about fishery resources and the efficient use of marine resources, yet the mesopelagic region is a relatively unexplored area.
The mesopelagic zone is known as the twilight zone since this begins at a depth where sunlight cannot penetrate. The epipelagic zone at the surface lies above it, where sunlight promotes photosynthesis and development. Yet, the levels of light in the twilight zone have become so weak that photosynthesis is almost nonexistent; therefore, scientists have long been curious about what happens down there.
When the Allies utilized echo sounders to identify and locate German submarines and mines throughout World War II, exceptionally strong hits to the echo signals suggested that an undetermined amount of biomass remained hidden in the deep water.
The authors hypothesize that the mesopelagic zone contains approximately 10 and 20 billion tonnes of shellfish and fish based on worldwide mapping. This volume is ten times bigger than earlier estimates, and it amounts to 90% of total fish biomass on Earth or around 1.3 tonnes of fish biomass for every human on Earth at the research time.
The Light in Twilight
Although the study's results were and continue to be subject to considerable ambiguity, they created a gold rush mentality, notably among some fishing, medical, and food businesses, who saw the potential for a new economic initiative.
The creatures and organisms that live in the twilight zone have a significant influence on the earth's natural carbon balance, as they assist the transfer of between 2 to 6 billion tons of carbon from the sea's surface to the ocean's depths, where it is preserved for hundreds of years, as reported by Phys.
This is also regarded as a biological carbon pump, so the danger of badly altering this natural mechanism by continuously trawling for the creatures that are a part of it is high. As a result, the researchers urged for worldwide study on the ecology and sustainability of twilight zone animals, and this was a critical aspect in the research that J. Rasmus Nielsen, alongside his colleagues, is working on in the present times.
The researchers send a trawl like this 200-1.000 meters into the sea to fish for species and plankton that can make them more aware of the ecosystem in the ocean's twilight zone.
Knowledge of Stocks is Essential
When fresh information about the glacial lantern fish or Mueller's pearl side arrives on J. Rasmus Nielsen's desk, one component, in particular, piques his and his collaborators' interest: species stocks and stock dynamics.
J. Rasmus Nielsen clarified that when they comprehend the dynamics of a biological supply, they also understand the surplus amount created and, as a result, how much they can extract from the stock sustainably. He and his colleagues, in particular, examine the dispersion of dimension, weight, and life stages of fish arriving from study sites in Spain, Norway, including Iceland. They utilize data from each place to determine a fish's growth and many life phases.
This provides a comprehensive picture of how the fish develop and spawn. Using statistical stock models, researchers may use this information to determine the stock volume and its reproductive capability. Furthermore, discrepancies in growth and death rates can assist in determining whether the fish in various places originate from the same breed.
According to early findings from the continuing study, the rates fluctuate between research fishing areas, implying that the fishes are also most likely from separate populations. The next phase is determining which stocks can withstand sustainable fishing and which cannot.
Future-Proof Food Resources
So far, it appears that he was correct in his prognosis. The research has already piqued the curiosity of the industrial fishing sector.
SINTEF, a Norwegian nonprofit research institute, has already made strides toward designing effective commercial fishing equipment for harvesting glacier lantern fish and Mueller's pearl side. Nofima, the Norwegian Food Institute, is working with ways to make Mueller's pearl side a desirable food item in the upcoming years.
Enzymatic hydrolysis is a biochemical procedure that involves mixing equal quantities of fish and water before adding enzymes. After roughly an hour, the enzymes are deactivated with heat, and the liquid is filtered away, leaving only the protein. They are then dried and consumed as a protein-rich meal.
Experiments with Mueller's pearl side have demonstrated that it is feasible to infuse the fish with diverse flavors; therefore, the next step is to determine whether the twilight zone snack offers commercial potential. J. Rasmus Nielsen becomes less hopeful, but it does not imply he is opposed to using these sources.
Overfishing Devastates Ocean Environments
According to J. Rasmus Nielsen, the UN appears to lack appropriate regional management organizations to handle mesopelagic fisheries, and there are no restrictions regulating fishing from specific stocks in a report from Messo.
As a result, J. Rasmus Nielsen, as well as other academics, are striving to educate managers and authorities on this importance, for example, through their involvement in the EU project. Over his numerous years of studies and advising on fisheries management, he has experienced the hazards and instances of overfishing in the fishing sector. As a result of bad management, we often lose huge fishing and economic possibilities while severely impacting marine ecosystems.
J. Rasmus Nielsen's research with the mesopelagic zone is more than a job. It is an opportunity to lay the groundwork for a more sustainable fishing sector in the future.
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