The fish farmer growing seaweed to feed cows and save the planet

Clean Harvest founder Josh Goldman.
Clean Harvest founder Josh Goldman. Photo: Louise Kennerley

In spite of the growing popularity of veganism and plant-based meat alternatives, humans remain massive consumers of livestock and dairy. The smelly reality of having 1.5 billion heads of cattle on the planet is that cows will always belch, pass gas and emit methane. It's little wonder that livestock (mostly cattle) accounts for between 14.5 per cent and 18 per cent of human-induced greenhouse gas emissions worldwide.

However, emerging research shows a naturally occurring red seaweed called asparagopsis taxiformis has the potential to significantly lower an animal's methane emissions when added to its feed. To date, scientists have had little success reproducing the red algae at scale due its complex life cycle, but that may be about to change.

Josh Goldman is chief executive of Massachusetts-based Australis Aquaculture and the environmentalist is on a mission to become a world leader in growing seaweed for cows. 

Smelly cows: Livestock account for up to 18 per cent of human-induced greenhouse gas emissions worldwide.
Smelly cows: Livestock account for up to 18 per cent of human-induced greenhouse gas emissions worldwide. Photo: Carla Gottgens

"If asparagopsis taxiformis was fed to all the world's cattle, it would have the environmental impact of taking every car of the road," says Goldman, visiting Australia this week to introduce his Clean Harvest branded barramundi to local chefs. 

Farmed in ocean waters off Van Phong Bay, Vietnam, Clean Harvest barramundi has more sustainability certifications than most other seafood products on the market. By using tuna industry byproduct as feed, Goldman says his farmed barramundi (native to the Indo-Pacific region) has an enhanced fat content that makes the fish more delicious and easy to cook with. 

The aquaculturist is most animated when discussing his success at enabling asparagopsis to reproduce with human intervention, however.

"We've recently been successful in getting large numbers of the seaweed spores to stick on ropes," he says. "The next step, which is happening in a few weeks, is transferring those ropes to our barramundi farms and cultivating the seaweed in the ocean."

Goldman says he firmly believes sea-based cultivation is the path to scale asparagopsis production and drive the cost down so it can be used by beef and dairy farmers around the world. 

"The cool thing is that farmers only need less than one per cent of the seaweed in their livestock feed to significantly reduce a cow's methane emissions," he says. "We're not out there trying to replace grass or corn - we're just sprinkling a little bit of salt and pepper on livestock feed to help the planet."

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Some research indicates asparagopsis taxiformis, which takes the gas-causing microbes in cow's gut out of commission, may reduce cattle methane emissions by up to 99 per cent. Goldman became aware of the red algae after reading a 2016 study of the seaweed by scientists at North Queensland's James Cook University and the CSIRO. At the time, he was looking for a seaweed that could not just increase the biodiversity of his barramundi farms and aid coastal regeneration, but take aquaculture's role in a sustainable food future to a whole new level. The red algae fit the bill.

"The ultimate aim is to harvest asparagopsis taxiformis as part of a cyclical farming system, but you don't have to be an existing farmer of barramundi or any other type of seafood to grow it," he says. "Anyone could lease a farm in conditions appropriate for the seaweed and cultivate it."

More research is needed to guarantee the seaweed is safe for human and livestock consumption, but so far trials suggest there's no impact on a cow's health or the taste of its meat and dairy products.

"We're hoping to support broader animal trials across James Cook and universities in the United States and Europe later this year," says Goldman. 

"For this to work we need many scientists and farmers in many places. Climate change is a pressing problem. While turning every car electric may be a 30-year undertaking, this something that could potentially be done a lot quicker."