A gut check on reducing bovine burps
Seafood has long been seen as the healthier option – for diets and for the planet. But the true emissions impact and biodiversity loss of seafood may be much fishier. Last week, a mindblowing report from Nature found that emissions from bottom trawling releases as much carbon dioxide as global aviation!
Seafood has long been seen as the healthier option – for diets and for the planet. But the true emissions impact and biodiversity loss of seafood may be much fishier. Last week, a mindblowing report from Nature found that emissions from bottom trawling releases as much carbon dioxide as global aviation! Said another way, if trawling for fish were a country, it would be the 6th most polluting global industry. For the past 50 years, global demand for fish has doubled the growth rate of the world’s population. Demand is only increasing, meanwhile we’ve exploited 90% of wild fisheries to (or past) their limits. Scientists predict that continued wild fishing will turn our oceans into virtual deserts in less than 35 years.
The finding on emissions from trawling and disappearing wild fish stock add new urgency to the shift away from wild catch fishing and toward improvements like aquaculture and alternatives like plant- and cell-based seafoods, where a bevy of oceantech entrepreneurs are hard at work innovating to protect our blue planet.
As the saying goes, there’s a lot of fish in the sea – but humans consume just four types of seafood species: fish, crustaceans, bivalves, and seaweed. As it turns out, the emissions range of seafood varies incredibly by species and production process.
The four major seafood categories of the seafood industry.
🐟🦐 Fish and crustaceans. Americans eat more shrimp than any other seafood species per year (with salmon a strong second) and demand is growing – production increased 500% over the last 20 years. Shrimp may be small, but their environmental footprint is mighty: farmed prawns emit 3x the GHGs of farmed fish. Shrimp aquaculture is also estimated to have destroyed 11% of mangrove habitat over the last two decades, a biodiversity and storm hazard. Shockingly, the carbon footprint of these farmed shrimp is higher than that of beef! (1603 vs 1440 kg CO2e / kg meat). Wild crustaceans also have a disproportionately high emissions profile (6% of seafood volume vs 20% of wild capture fishing emissions.)
🐚🌿 Bivalves and seaweed. These slippery, less sentient seafood cousins conversely have a mostly positive environmental impact, as shelled mollusks and seaweed don’t require food to grow and provide added water filtration benefits. To boot, seaweed trumps terrestrial plants in its ability to absorb CO2 while helping de-acidify water, supporting other nearby species including – you guessed it – bivalves. Commercially, seaweed is gaining attention for its growth rate which is between 10-30 times faster than terrestrial plants. (The recent market action in seaweed for feed, alternative protein, materials, and as a carbon sink is outside the scope of what we’re focused on here – but may warrant a future feature!)
Half of global seafood consumption is still produced the old way – wild and straight from the source. In developing countries where 97% of fishermen live, wild capture fisheries constitute a higher ratio of production and are an essential part of the economy. With 90% of marine fish stocks now fully exploited, overexploited, or depleted, the industry itself is at risk of collapse. Fuel to travel to and from fishing grounds accounts for the primary source of emissions in wild capture fishing, and as fish stocks wane, fishermen must burn more fuel to travel further from the coast. During the hunt, global fishing fleets dump approximately 10% of the fish they catch back into the ocean as discards.
Novel tools are empowering fishermen with technology to bring down their costs while reducing bycatch waste and capturing data on global fish stocks.
Aquaculture production has tripled in the last two decades, and is expected to continue taking share from wild capture fisheries. Fish farming either takes place in the ocean or freshwater using open-net pens or cages (net-based) which allows for free exchange of waste, chemicals, parasites and disease, or in closed land-based systems which requires significant energy and water to recreate ideal aquatic conditions. Aquaculture’s production emissions are primarily driven by feed and energy use – but vary widely by type of operation (e.g, land-based salmon production has a 28% higher carbon footprint than net-pen salmon farms). “Many of the sustainability issues related to fish farming stem from its scale. A higher density of cages means more waste into the ocean, a higher chance of escapes (which disrupt the wild population), and more pests/disease. This means the potential impact of building a more sustainable aquaculture industry is enormous,” explains Tony Chen, CEO of Manolin. His company and others are improving the sustainability of aquaculture via technology for feed, precision farming, and fish health.
New feed alternatives. Feed contributes 57% of aquaculture emissions through ingredient production, processing, and transportation. Historically 20%-35% of wild fish capture was converted into fishmeal for feed which meant that aquaculture exacerbated rather than relieved pressure on wild fish populations. Fish farms are increasingly transitioning to plant-based feed, meaning “that salmon on your plate might have been vegetarian.” Still, land used to grow the crops to feed the fish accounts for 39% of aquaculture’s GHGs. A school of startups are working to solve the emissions-intensity of fish feed by replacing crop-based feed with insects and even captured carbon dioxide emissions.
Remote fish farm productivity monitoring. Precision farming tools have turned the tide on land and now emerging data tools leveraging IoT and AI/ML are driving more productive and sustainable fish farms. Aquatic farms face unique challenges (e.g., toxic nitrogen levels from fish waste, algae blooms, shifting oceanic temperatures and acidification). Remote monitoring detects farm conditions such as feed consumption or water health, while predictive data analytics optimizes for better conditions to improve yields. Efficiency is the name of the game where fuel-intensive aquaculture maintenance routines by boat constitute ~20% of farm emissions.
Programs to certify responsibly farmed seafood hinge on annual in-person audits and as a result, certification is astonishingly low – there are <2,000 certified shrimp farms today. Likewise, most aquaculture establishments are smallholders, who lack crucial support services such as local feed and equipment suppliers. Sea Warden is improving farmer access to climate smart production resources. “Our platform uses satellite technology to optimize the delivery of critical resources and technicians to at-risk shrimp farms. We also provide shrimp farmers with remote monitoring as an effective, low-cost verification tool to ensure aquaculture production is conducted responsibly and improve farmer access to certification,” CEO Zack Dinh explains.
Fish health is sustainability. Around 20% of fish die during production. Disease and lice can dramatically swing aquaculture’s resource efficiency and emissions – not to mention welfare of the farmed fish, or potential infection of wild populations. Norway’s salmon farming industry boasts the gold standard of fish farming health and sustainability through their mandatory sea lice reporting and the virtual elimination of all antibiotics. Startups are spreading the best practices to fish farmers worldwide through tools to monitor sea lice, detect risk of disease and oxygen levels, and through fish vaccines and oral biotherapeutics that reduce the need for antibiotics and chemicals. Manolin uses machine learning to build fish disease detection models to warn farmers of disease risk with more than 93% accuracy. “During our time in Norway, we found that salmon farmers already collect an enormous amount of data, but it’s inconsistent, incomplete, and sits in silos. We saw this as an enormous opportunity to improve sustainability and collected thousands of data points on farm activity to fuel our disease prevention models,” Tony Chen, CEO of Manolin explained.
“The last frontier” of plant-based meat is in seafood, making up only ~1% ($9.5m) of US plant-based meat sales. “That’s partly because consumer packaged goods have tended to favor burgers, hotdogs, chicken nuggets and other foods. Kuleana goes beyond the fish stick approach. We’re enabling professional chefs and home chefs alike to make sushi rolls and poke bowls that have the right texture, flavor, and appearance” noted Jacek Prus, CEO of Kuleana which makes plant-based sashimi-grade tuna. While soy and peas remain common ingredients, a few plant-based seafood producers have formulated their seafood meat substitutes with environmentally-friendly and nutrient-rich seaweed.
At the frontier of the frontier, cell-based seafood is in even earlier days. The entire cell-based product can be consumed with no by-product waste, and without the need for any plant inputs resources. However, cell-based meat has a longer timeline to production at commercial scale.
Special thanks to Pale Blue Dot, a Sweden-based climate tech venture firm investing in startups that reduce and reverse the climate crisis and help us prepare for a new world, especially Alice Carlson.
A gut check on reducing bovine burps
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