Tag Archives: seafood

Turning leaked methane into fishmeal would turn a profit while helping the environment

The issue of methane pollution might become an asset in the future, thanks to new technology that can transform this potent greenhouse gas into fish food.

Image credits Sirawich Rungsimanop.

Approaches to converting methane into fishmeal have already been developed, the authors note, but the economic uncertainty during the pandemic has prevented its use to promote food security on any meaningful scale. The new study analyzes the method’s economic viability today. The main takeaway of the research is that methane-to-fishmeal conversion is economically feasible for certain sources of the gas and that other sources can be made profitable with certain improvements.

The approach can also be of quite significant help against climate change, the team adds, and is capable of meeting all the global demand for fishmeal, further reducing the strain we’re placing on natural ecosystems.

Untapped resource

“Industrial sources in the U.S. are emitting a truly staggering amount of methane, which is uneconomical to capture and use with current applications,” said study lead author Sahar El Abbadia, a lecturer in the Civic, Liberal and Global Education program at Stanford.

“Our goal is to flip that paradigm, using biotechnology to create a high-value product.”

Carbon dioxide is the best-known greenhouse gas, and currently the most abundant one in the Earth’s atmosphere. That being said, methane is another important player in our current climate woes. Methane is estimated to have 85 times the global warming potential of CO2 over a 20-year period, and at least 25 times as great a potential over a 100-year period. Methane also represents a direct hazard to public health as concentrations of this gas are increasing in the troposphere (the lower layer of the atmosphere, where people live). An estimated 1 million premature deaths occur worldwide, per year, due to respiratory illnesses associated with methane exposure.

The problem posed by methane is also increasing over time: the relative concentration of this gas in the atmosphere has been increasing twice as fast as that of CO2 since the onset of the Industrial Revolution, the team explains. Although there are natural sources of atmospheric methane, mostly through the decomposition of organic matter and from digestive processes, the lion’s share of that increase is owed to human-driven emissions.

Methanotrophs, bacteria that consume methane, have been explored as a potential solution in the past. If supplied with methane, oxygen, and certain nutrients, these bacteria produce a protein-rich sludge that can be used, among other things, to produce feedstock for fish farms. This process is already in commercial use by some companies; however, they are supplied by methane fed through gas distribution grids.

The authors note that capturing methane emissions — such as those from landfills, wastewater treatment plants, or leaked at oil and gas facilities — would be both cheaper and much more eco-friendly. Besides economic and environmental benefits, the shift from pumped to captured methane in the production of fishmeal would also help ensure humanity’s greater food security. The authors explain that seafood consumption has increased more than four times since the 1960s, with grave consequences for natural fish stocks.

Aquaculture (fish farms) now provide around half of the quantity of animal-sourced seafood consumed globally. Demand for seafood in the form of algae and animals is also estimated to double by 2050, the team adds, which will place increased strain on producers.

Against this backdrop, methane-sourced fish feed can represent an important asset towards food security in the future, and allow us to have the seafood we crave for minimal environmental impact.

Makes economic sense

Unused methane emissions in the U.S. from landfills, wastewater treatment plants and oil and gas facilities. Image credits El Abbadi, et al., (2021), Nature Sustainability.

In order to determine whether such efforts would also be economically-feasible, the team modeled several scenarios, each with a different source of methane used in the production of the fishmeal. These included natural gas purchased from commercial grids, as well as methane captured from relatively large wastewater treatment plants, landfills, and oil and gas facilities. For each scenario, they looked at a range of variables that would factor into a company’s bottom line, including the availability of trained labor and the cost of electricity used to keep the bioreactors running.

In the scenarios that involved methane capture from landfills and oil & gas facilities, the production cost for one ton of fishmeal would be $1,546 and $1,531, respectively. Both are lower than the 10-year average market price of such products, which sits at $1,600. In scenarios in which methane capture was performed at wastewater treatment plants, the cost per ton sat at $1,645, which is just slightly over the market average. However, the highest prices per ton were seen when methane was purchased directly from the commercial grid — $1,783 per ton.

Surprisingly enough, electricity was the single largest expense for all scenarios, representing around 45% of total costs on average. This means that areas with low electricity production costs could see significant decreases. The authors estimate that in states such as Mississippi and Texas, these costs would go down by around 20%, to an average of $1,214 per ton ($386 less than the 10-year average).

With certain improvements, such as bioreactors with more efficient heat transfer to reduce the need for cooling, production costs can be reduced even further. Even in the scenarios where wastewater treatment plants provided the methane, steps can be taken to reduce costs. For example, wastewater itself can be used as a source of nitrogen and phosphorus (key nutrients), as well as for cooling.

The team estimates that if manufacturers can bring the per ton production cost by 20%, there would be profits to be made even if all the supply of fishmeal today was covered using methane-produced materials with gas captured in the U.S. alone. With ever more reductions in cost per ton, such products could out-compete soybean and other crops for animal feed in general.

“Despite decades of trying, the energy industry has had trouble finding a good use for stranded natural gas,” said study co-author Evan David Sherwin, a postdoctoral researcher in energy resources engineering at Stanford. “Once we started looking at the energy and food systems together, it became clear that we could solve at least two long-standing problems at once.”

The paper “Displacing fishmeal with protein derived from stranded methane” has been published in the journal Nature Sustainability.

Mollusks are the most plastic-filled seafood in the world

New research found that marine mollusks such as mussels, oysters, and scallops, contain the highest levels of microplastic contamination of all seafood.

Image credits Pixabay.

The team, led by members from the Hull York Medical School and the University of Hull has analyzed over 50 studies on the topic of microplastic contamination in seafood. These were published between 2014 and 2020 and worked with species ranging from fish to shellfish all around the world.

Food with a little extras

“A critical step in understanding the full impact on human consumption [of plastics] is in first fully establishing what levels of microplastics [MPs] humans are ingesting,” says Evangelos Danopoulos, a postgraduate student at Hull York Medical School and co-author of the paper. “We can start to do this by looking at how much seafood and fish is eaten and measuring the number of MPs in these creatures.”

Microplastics are produced by the breakdown of larger plastic particles as they decompose slowly; some are produced outright, as additives for cleaning or beauty products. Eventually, they make their way into waterways and the ocean through wastewater. Once there, MPs often become ingested by wildlife that confuses it for bits of food. Microplastics resist digestion and build-up in the animals’ bodies.

Whenever we eat seafood, then, we’re also taking in the plastics they ingested over their lifetimes. MP contamination is not limited to seafood, but it is more pronounced here than in any other type of environment. The team found microplastic content ranged between 0-10.5 microplastics per gram (MPs/g) in mollusks, 0.1-8.6 MPs/g in crustaceans, 0-2.9 MPs/g in fish.

“Microplastics have been found in various parts of organisms such as the intestines and the liver,” says Danopoulos. “Seafood species like oysters, mussels, and scallops are consumed whole whereas in larger fish and mammals only parts are consumed. Therefore, understanding the microplastic contamination of specific body parts, and their consumption by humans, is key.”

“No-one yet fully understands the full impact of microplastics on the human body, but early evidence from other studies suggest they do cause harm.”

China, Australia, and Canada are the largest global consumers of mollusks, the team also found, followed by Japan, the US, Europe, and the UK. Those captured off the coasts of Asia tended to see the highest levels of contamination, suggesting these areas are the most heavily polluted with plastics and microplastics.

The findings showcase the sheer extent of the plastic pollution problem facing our planet. Production of such materials is expected to triple by 2060, meaning it will only get worse and worse in the future unless steps are taken soon. For that to happen, however, we need to get a clearer image of the problem, and the team explains that we need standardized methods of measuring microplastic contamination levels, and more on-the-ground data to see how different oceans and waterways are impacted by them.

The paper, “Microplastic contamination of seafood intended for human consumption: a systematic review and meta-analysis” has been published in the journal Environmental Health Perspectives.

Endangered fish species are legally being sold as seafood

We might unwittingly be eating endangered fish species as part of our diet, according to a new study which found that almost 100 endangered species that are being sold as seafood across the globe — legally. The researchers warn that the problem could be even greater than we believe, and called to keep endangered species off the menu.

Credit Flickr Llee_Wu

A team from the University of Queensland looked at records between 2006 and 2014 and found 92 endangered and 11 critically endangered species of seafood where caught and sold, 13 of them internationally. When sold, they aren’t required to be labeled according to species, so consumers don’t know what they are eating.

While the numbers are worrying, they are only a snapshot of the real problem, the researchers warned. In the study, they only looked at reported catch and imports and didn’t look into illegal and unreported fishing. They also excluded groups of fish such as rays or sharks, a popular meal in Australia, Europe, and Asia.

“Species that aren’t cute like whales or sea turtles often don’t end up getting the protection they deserve,” first author Leslie Roberson told ScienceAlert. “Despite national and international commitments to protect threatened species, we actively fish for many of these threatened species.”

The expansion of seafood

Seafood is an important source of protein for billions of people globally, with over 80 million tons of marine animals taken from the ocean annually for consumption. Fishing is the primary driver of declines in marine biodiversity. One-third of fished stocks are exploited at biologically unsustainable levels.

Some populations of threatened fish and invertebrates are closely monitored using fisheries stock assessments. Nevertheless, they are treated differently than other wild animals and are allowed to be caught in industrial fisheries, regardless of the species’ global conservation status.

“While we have yet to fish a widely abundant marine fish or invertebrate species to extinction, we have fished populations or stocks to local or functional extinctions, such as totoaba in Mexico, sturgeons in Europe, and white abalone in California. Many stock collapses have been small, short-lived species, proving that slow-growing and long-lived animals are not the only ones at risk,” the researchers wrote.

The study found European countries play a central role in driving the exploitation of threatened fish and invertebrates. Nevertheless, developed countries with greater monitoring and management capacity tend to have higher resolution catch and import records, which likely leads to more records of threatened species.

Solutions ahead

There are some ways to untangle the mess we’re creating in the world’s oceans, the researchers argued. Consumers should be able to purchase seafood from a well-managed stock that is secure on a global scale. But this would require changing the structure of the seafood supply chain, as its currently very difficult to make informed purchases.

At the same time, the traceability of species across the seafood supply should be improved. The researchers argued it’s possible and cost-effective to identify an animal and trace it to the consumer using emerging technologies such as electronic monitoring, DNA testing, code tags, blockchain, data mining, and artificial intelligence.

“Efforts to preserve marine biodiversity and maintain viable ecosystems will fail if we focus only on charismatic species or individual stocks. We need to treat fish and invertebrates as wild marine animals as well as seafood commodities, better align conservation assessments and fisheries management frameworks, and reduce fishing pressure that is pushing species towards extinction,” the study concluded.

The study was published in the journal Nature Communications.