The UN warns that invasive species could cost the world at least $423 billion each year as climate change worsens. Although some wild introductions are benign, many pose serious risks to biodiversity and ecosystem health around the world.
Armed with unique adaptive advantages, a species introduced too rapidly in a new habitat can easily outcompete existing wildlife. Without natural limits on their reproduction, they can reach numbers that strain the environment’s carrying capacity and reduce other wildlife, including species that human livelihoods depend on.
The bioeconomy can play an important role in managing the problem. Invasive species offer not just high volumes of biomass but are among the most sustainable feedstocks available for bio-based industry.
Often only a careful life-cycle assessment can reveal whether a bio-based product is better for the environment overall than an equivalent fossil product. What makes biomass from invasive species such a rare opportunity for the bioeconomy is that they present an instance where large-scale harvesting is almost guaranteed to bring a net environmental benefit.
Although businesses that draw on invasive biomass are still relatively niche, numerous startups in the US are now turning these natural surpluses into high-demand consumer and industrial products, helping to restore afflicted habitats in the process.
The great Zebra Mussel invasion
Zebra Mussels’ native homes are the lakes of southern Russia and Ukraine. Since arriving in North America in the eighties as stowaways on European trade ships, their populations have exploded in the Great Lakes of east-central North America and across the Mississippi River watershed.
Zebra Mussels only reach 3-4 cm in length but their large populations are having outsized impacts on these grand aquatic ecosystems. They have become so numerous that they are depleting stocks of the wild algae which many other species rely on.
AntiMussel is a Wisconsin startup that has found a commercial outlet for this troublesome mollusc. Their objective is to turn large volumes of their shells into renewable, low-impact feedstock for calcium carbonate, an ingredient used by the paint and plastic industries.
Right now, calcium carbonate mainly comes from limestone – a mined mineral that is contributing to the environmental harms attached to today’s solvents industry.
Mined resources like limestone take millions of years to form and just a few decades to deplete. Not only is it a limited store of resources, but mining is also extremely damaging to the ecosystems that sit on top of deposits.
The company nabbed $20, 000 in January 2023 for a pilot programme to start removing the Zebra Mussel from Lake Michigan. It is now on the hunt for a corporate partner keen to cut emissions with a lower-impact input.
Former pets become pet feed
Around North and South America, there is another aquatic invader that presents the bioeconomy with a large potential feedstock source: the armoured catfish.
It is believed that today’s wild armoured catfish populations are descended from escapees of the pet aquarium trade in the 1950s. In a serendipitous turn of events, US B-Corporation Pezzy Pets is now turning them into dog and cat food.
Co-founder Mike Mitchell first came upon the idea of commercialising the species in Mexico, where he encountered small fishing communities being devastated by the animal’s impact on aquatic ecosystems.
So far the company estimates it has removed 100 tonnes of armoured catfish in Southern Mexico.
Pezzy Pets has also expanded into using silver carp and lionfish, two other invasive fish that are widespread across the Americas. The company now employs around 100 fishermen to collect the animals individually through spearfishing and scuba diving.
Ordinarily, fish is a precious and over-drawn resource. Around the globe, high-value species are on the decline with populations weakened by a century or more of over-exploitation. Drawing on pockets of invasive fish in particular ecosystems, however, lets us tap the nutritional benefits of aquatic organisms without unbalancing habitats.
Invasive resources demand creativity
Research conducted in the Caribbean and Mediterranean also suggests that targeted removals do work to reduce invasive species’ population sizes, meaning that commercialising hazardous biomass can be a viable form of environmental management.
Yet actually finding commercial uses for new ecological arrivals can be a challenge, often requiring companies to be creative in identifying applications where invasive species could seamlessly replace more environmentally harmful feedstocks.
In the US, for example, the silver carp used in Pezzy Pets feed is classified as an invasive fish with no commercial value. Researchers and culinary professionals have wracked their brains for marketing the species as a palatable culinary adventure for human consumers. Pezzy however recognised that other mammals are not so picky about where their platters come from.
Apart from the ecological remediation work that its harvesting offers, Pezzy is also presenting a sustainable model for the rest of its industry. The carbon and land footprint of nutritionally rich pet food is high and invasive species offer an alternative stock of biomass to deliver sustainable health for companion animals.
Pezzy’s leap of faith into the sustainable pet food market shows how a formerly under-valued and ecologically problematic resource can find unexpected new markets.
Inversa is another company drawing down harmful lionfish populations by putting them to use as a substitute for mammal hide leather.
Leather has proved among the most difficult apparel fabrics to replicate using renewable materials. Startups now abound offering fungi and cacti-based versions and Inversa has added invasive fish to the mix.
Inversa says their catfish leathers revive ecosystems around the world, drawing their feedstock from the Mississippi River and the Gulf of Mexico, where populations are scarring sensitive reef ecosystems by killing huge numbers of young reef fish.
Invasive python raises ethical questions
In 2022 Inversa turned to a more controversial species for its leather goods: the Burmese python. This particular species inhabits the Florida Everglades in large numbers but are a highly destructive recent introduction that grew from a few pet escapees from the 1980s and 1990s.
Counting how many Burmese pythons now live in the Everglades is difficult but ecologists know they have been extremely successful in taking over the ecosystem. One sign is that there have been large declines in mammal populations in areas where the python has resided longest. A 2012 study showed racoon populations in the remote southern regions of the park had dropped 99.3% since 1997.
Commercialising the Everglades’ Burmese python population could bring this particular ecosystem back into balance. Yet in some parts of the world, the leather trade is driving endangered reptile species to extinction.
This brings an important principle of bio-based feedstock to the fore: what is a highly ecologically destructive industrial feedstock in one context may be an ecologically beneficial one in another. This becomes starker when we consider that invasive feedstocks could either be plants or animals, upsetting the standard association between plant-based products and sustainability.
This means that invasive species feedstock can sometimes pose a conundrum for vegan consumers. If sentient species are destroying habitats, and drawing on them can divert demand away from industrially slaughtered animals or endangered species, is the use of invasive animals preferable to using plant-based feedstock?
Some would argue that from an animal rights perspective, plant-based products are always superior no matter what the conservation status of the animal in question. Another argument could be that using invasive pythons for fashion could have the unintended effect of increasing wider demand for reptile skin, encouraging illegal poaching for endangered reptiles.
The idea that the skins of wild python could count as a sustainable raw material is more likely to prompt ethical objections than killing invasive fish perhaps because they more closely fit the image of what an endangered species looks like.
Yet from an environmental health perspective, aany species in the wrong ecological context can be harmful, meaning there is little separating the use of knotweed, catfish, or python for industrial uses. From this angle, deciding whether using sentient invasive species as feedstock is ethical will largely come down to whether they are killed humanely and sustainably – something that applies to fish or vertebrates.
A growing problem and a growing resource pool
Finding strategic uses for invasive biomass will become important as climate change rapidly alters the boundaries between longstanding ecological zones. This will accelerate the number of invasive species around the world, posing a growing problem and a growing resource pool for the bioeconomy at the same time.
Monitoring efforts by governments is crucial for helping actors in the bioeconomy devise new ways to valorise this stock. Regularly updated public lists of invasive feedstock could spur more enterprises to specialise in exploiting ecological hazards. More partnerships between businesses and authorities responsible for ecological management could also spur new demand for products that remediate unbalanced ecosystems and displace fossil materials in the process.