Sustainable Aquaculture and Food Security: Herbivorous Fish and Algal Feeds

Nov 23, 2020 | 0 comments

Aquaculture is one of the fastest growing food sectors in the world, estimated to be contributing up to two-thirds of global seafood consumption by 2030. With the world’s population set to increase to almost 9.7 billion by 2050, sustainable aquaculture has a vital role to play in contributing towards food and nutrition security and sustainable and healthy diets for all. A key priority for the aquaculture industry must be scaling up the sustainable production of herbivorous species of fish – those fish that eat plants, with a focus on feeds such as algae and insects as an alternative to soya and fishmeal. Sustainable aquaculture must be a key priority for governments, investors, and businesses alike.

Aquaculture – A Growth Industry

Aquaculture is currently the world’s fastest growing food industry, and now accounts for 53% of all fish consumed globally. By 2030, aquaculture could provide up to two-thirds of global seafood consumption according to the Food and Agriculture Organisation (FAO). The UNs latest State of World Fisheries and Aquaculture Report, stated global fish production is estimated to have reached about 179 million tonnes in 2018 with a total first sale value estimated at USD 401 billion. Global food fish consumption has increased at an average annual rate of 3.1 percent from 1961 to 2017, a rate almost twice that of annual world population growth for the same period. Countries in Asia accounted for about 89% of global production in 2016 with some 3 billion people worldwide relying on fish (wild-caught and farmed) as their main source of protein.

Figure 1- Showing the Rapid Growth of Aquaculture Since the 1960’s

Aquaculture is projected to continue grow by 1-2 percent per annum (according to the World Bank) over the next decade as population continues to grow to an estimated 9.7 billion people by 2050. This growth will also be driven by increased consumer demand for fish as a healthy and nutritious alternative to other red and white meats.  

With 3 billion people relying on wild-caught and farmed seafood as a primary source of protein, aquaculture plays a vital role in meeting the worlds future food security needs.  Aquaculture products are a healthy, nutritious, accessible, and affordable source of protein for many people. Under certain circumstances, and with the right choice of species, aquaculture can become the most efficient and sustainable way of producing animal protein and make a significant contribution to the economic prosperity of local communities within some of the poorest countries in the world,

Sustainable Aquaculture

It is my believe that aquaculture done well is key to easing pressure on existing wild fish stocks and to addressing the protein deficit in parts of the developing world (especially in parts of Africa and SE Asia). If the environmental impacts of aquaculture can be addressed, the industry has a vital role to play in providing healthy, nutritious forms of protein without destroying the planet. Compared to other animal proteins, fish have a favourable feed conversion ratio (FCR) which coverts feed to weight; for fish, it’s about 1.8kg of feed to 1 kg fish protein by weight, whereas for beef, it’s about 8:1.

Whilst a number of sustainability impacts from aquaculture need to be addressed ( local pollution of water bodies, parasites contaminating wild fish populations, animal welfare standards and worker conditions to name some of those common issues), the most significant environmental impact of aquaculture is fish feed – feeds based on fishmeal and soya continue to predominate across the sector. 

Fishmeal based feeds use wild-caught forage (pelagic) fish like anchovies, pilchards, mackerel and sardines, millions of tons of which are harvested from our seas each year, result in over 90% of wild fish stocks which are now depleted or degraded( according to WWF). In addition, soya, the other main ingredient used in aquaculture feedstocks, drives deforestation and land conversion in the Amazon which in turn contributes to biodiversity loss, greenhouse gas emissions and soil degradation.

What is needed to scale sustainable aquaculture solutions?

Below I highlight just 3 of the most significant opportunities to scale sustainable aquaculture solutions ( although others are also required):

1) The need to focus on herbivorous fish production – We need to focus our attention on herbivorous fish and move away from the growth in the production of carnivorous fish, such as salmon, seabass and trout, that require significant quantities of more resource intensive and destructive fishmeal and soya.

There are significant opportunities to scale up production of lower impact more herbivorous fish, such as tilapia, pangasius or bivalves such as molluscs or shellfish (those lower tropic level, plant eating species). These tend to be lower in capital intensity and inputs and thus, more accessible, compared with higher-intensity species, such as Salmon, which use higher impact fish meals and fish oils as feed. From a feed perspective, as their name suggests, herbivorous fish only feed on plants and are as a consequence more efficient convertors of protein into fish flesh.

2) Fish feed Innovation on sustainable alternatives to fishmeal and soya:

As discussed above, it is how fish are fed that is the most significant factor contributing to the aquaculture industries environmental footprint. Feed inputs for aquaculture production represent 40–75% of aquaculture production costs and are also a key market driver for aquaculture production. To reduce aquacultures footprint more research and investment needs to focus on fishmeal and soya – These include the likes of algae, bacteria from methane production or microbial proteins from carbon dioxide sequestration.

Recently a group of researchers reported in Nature, that they might have a solution in the form of a new, completely fish-free aquaculture feed, developed from marine algae. They combined two commercially available microalgae, to produce a high-performing fish-free feed for Nile tilapia – the world’s second largest group of farmed fish. The tilapia that were nourished with this new green diet showed a striking 58% gain in weight, compared to the tilapia that received conventional fish feed.

Another example are novel feed proteins for farmed fish produced via gas fermentation  – Recently Calysta, a California-based biotech company has recently created a joint venture with Adisseo, a specialist producer of feed additives for animal nutrition, to produce “Feedkind”.The companies claim that it can be manufactured without using any arable land and almost no water. They are planning to start production in China in 2022, supplying the growing Asian aquaculture markets, aiming to produce 20,000 tonnes of the feed per year initially.

3) Support for Smallholder Fisherfolk Networks – Big is not always best when it comes to aquaculture production. With appropriate support, small scale aquaculture initiatives could expand rapidly in Asia, Africa and South America, as a tool for rural development, creating additional jobs, increasing incomes and providing healthy nutritious protein foods for those communities most in need.  The need to support fisherfolk centred knowledge transfer and support networks are crucial to the success of improving production techniques/practices and to support fisherfolk to distribute, process and market their fish.

There are lots of great examples of fisherfolk networks from around the world NutriFish for example empowers poor, rural women where they live with culturally acceptable livelihood and safe, reliable, diverse and nutritious food for them and their families. They provide reliable, macronutrient-dense food for women and children in their first 1,000 days of life, while keeping women in control of food production. WorldFish is another non-profit that highlights sustainable fishing and aquaculture methods through its research, as a way to reduce poverty and bolster food and nutrition security across Africa, Asia, and the Pacific.

Despite the potential benefits sustainable aquaculture can play in providing affordable, healthy, and nutritious foods for a growing global population, I feel that aquaculture still does not receive the attention it deserves from governments, businesses, and investor organisations. 2021 is a critical year for our food system – We have the food system summit in New York, the Convention on Biological Diversity and COP 21 – and yet aquaculture is often noticeable by its absence in these discussions compared to agriculture more broadly. My hope is that more attention sustainable aquaculture with a focus on innovation, policy and practices which regenerates our oceans and lands whilst building long term resilience and profitability for the sector.

16810cookie-checkSustainable Aquaculture and Food Security: Herbivorous Fish and Algal Feeds

Written By Tasting the Future

Mark Driscoll is a freelance sustainable food systems consultant focussing on food systems transformation initiatives. He works with businesses, funders and civil society organisations on a range of food systems projects. This includes research work, strategy & policy development, project management and media work. He is a passionate advocate and champion of food systems transformation which gives citizens access to healthy and nutritious foods within environmental limits.

Related Posts





  1. Farming omnivorous prawn – it’s what 90% do globally with domesticated pacific white vannamei…. – Prawnmaster's Blog - […] Sustainable Aquaculture and Food Security: Herbivorous Fish and Algal Feeds. farmed vannamei shrimp … […]
  2. Halt extractive fishing fleets in our oceans to restore marine ecosystems #Regeneration #Fishing #auspol #EcologicalCrisis – Climate Action Australia - […] fish like tilapia and catfish take fewer resources from the environment to grow and are thus less wasteful to […]

Leave a Reply

Subscribe to the Blog

Enter your email address to subscribe to this blog and receive notifications of new posts by email.