Mixed-sex Nile tilapia can perform competitively with mono-sex fish in cage culture

In this episode, Dave Little talks with Reed Ozretich who specialises in a One Health approach to aquaculture in the context of a changing climate. He's been working on a Belmont-funded project in Brazil and Ivory Coast coordinated by Giulio de Leo, at Stanford University, but working with local partners focusing on understanding the dynamics of snails as vectors for schistosomiasis; what, if any, is the role of farmed fish in controlling them? Reed talks here about his recent work in Ivory Coast with Professor Eliezer N’Goran. at UFHB in Abidjan.

Researchers discuss a comparative production trial between mixed-sex and conventional all-male stocks of tilapia farmed in cages in Thailand. This showed that males can perform as well in mixed-sex culture and that smaller females can boost total cage production. Financial analysis demonstrated why this is not current practice, but indicated that if a market premium could be obtained for non-sex-reversed fish, and/or smaller fish sold into markets where these command a higher price, this could become a more attractive strategy with wider social benefits.

In this podcast, Professor David Little talks with Associate Professor Abdullah-Al Mamun from the Department of Fisheries and Marine Science at Noakhali Science and technology University, Bangladesh, about the findings of his research among shrimp farming communities in South West Bangladesh which was carried out in collaboration with the Universities of Stirling and Aberdeen. This large-scale study found that the export-driven culture of shrimp supports local livelihoods with positive contributions to public health and prosperity, whilst being climate-resilient, contrary to its reputation. The study was conducted over four years, collecting quantitative and qualitative data from 240 households and 160 shrimp-prawn farms in four different communities.The study found that a relatively small amount of the total production was exported and that local sales of shrimp as well as co-production of other species provided important income for communities, had a low impact on the environment, whilst providing crucial nutrition.The research found that only 20-40 per cent of all the fish produced – the shrimp and prawn - was destined for export, with a high diversity of other fish being produced, sold and consumed locally in mainly small-scale enterprises.

Freshwater aquaculture dominates global aquaculture production, but its importance is often overlooked in global food-policy agenda and research. In a new study published in Nature, Dave Little and Richard Newton at the Institute of Aquaculture, University of Stirling and external colleagues led by Dr Wenbo Zhang of Shanghai Ocean University argue that recent research underestimates the production potential for freshwater aquaculture and inflates the importance of mariculture, or saltwater aquaculture. In this podcast, Professor David Little talks with Dr Wenbo Zhang about the study and the paper that prompted it.

In this episode Dave Little is interviewing Dr. Richard Newton, who discusses his work on the idea of ecologically responsible intensification of fish farming through improvements in farming efficiency and the reuse or repurposing of waste products throughout our supply chains.Intensification in aquaculture generally means producing more from a specific limited or expensive resource - e.g. land area or tank space. However, this approach can too easily have negative consequences when viewed through a broader lens of sustainability. The EU GAIN Project therefore adopted the concept of “eco-intensification”, to indicate that intensification would be more multi-dimensional in terms of parameters considered and solutions developed. A key approach was to consider not just the aquaculture production activity, but the whole value chain, particularly opportunities for integrating elements into circular economies. This essentially means finding ways of utilising and generating value from waste or by-products either into or out of the aquaculture value chain. This for instance includes better utilisation of fish processing waste e.g. by transforming them into a material that can be used as a feed ingredient for another species, or for fine chemical extraction or input to new biomaterials.

Wesley Malcorps explains how a large proportion of the fish farmed in Europe is discarded, sometimes up to 50% of the whole fish. However, this is dependent on the consumption habits, generally speaking, the north of Europe prefers fillets, while the south of Europe prefers the purchase of whole or gutted fish. This has an impact on the availability of by-products at the processing stage. Reducing waste reduces environmental impacts in a number of ways but sustainability analyses of aquaculture has typically ignored the fate and value of processing by-products. Because of the nutrient content, fish by-products have applications in human food, livestock and pet food. However, there are also some barriers to overcome, including consumer acceptance of different product forms.

As part of the EU GAIN Project, Wesley Malcorps and other project partners visited seafood trade exhibitor booth messaging strategies in China, which is the largest seafood producer in the world by volume. They also observed trading booths in Europe and America. These are considered the major seafood consuming regions in terms of value. They observed logos and word use on booths in Brussels, Boston and at three shows in China (Guangzhou, Qingdao and Shanghai) to determine the key messages communicated by seafood sellers to their buyers.European and American seafood traders showed a high interest in “sustainability” messaging, which is driven by consumer demand for ecolabels and sustainable production practices, while Chinese traders showed a relatively higher interest in messaging around “safety” and “quality”.The use of “safety” messaging can be traced back to concerns around food safety and efforts to address public concerns related to public health scandals.The use of “quality” messaging is strongly associated with signalling about the natural characteristics and health benefits of seafood consumption in the Chinese market.

Professor Dave Little talks with early career researcher and GAA Innovation Award Winner Dr Simao Zacarias about his work on developing higher welfare practices for producing white-legged shrimp and on developments within the shrimp industry to reduce environmental impacts and contributions to greenhouse gas emissions.Some of the key points raised in the discussions are how:improvements in feed quality, source and management have been key approaches to reduce the impact of feed in shrimp farming GHG emissions. the adoption of annual mangroves forestation programs is reducing the impact of mangrove clearance on GHG emissions.the shift to intensive systems enables minimal use of land and water, and reduces the environmental impacts.adopting high welfare farming practices improve shrimp wellbeing and robustness.

In this episode, Professor Dave Little speaks with researcher Alexandra Pounds about her work studying the evolution of decentralised rice-fish fingerling production in North West Bangladesh; its importance for income generation, nutrition and community health, and how this is being affected by climate change. Alex’s research focuses on livelihood and health outcomes of aquaculture.

Professor Dave Little talks to researcher Stephanie Horn about her work in Bangladesh. This involves looking at the nutritional and environmental impacts of different culture technologies, including the introduction of GIFT tilapia. The aim is to identify the most resilient and sustainable farming systems that can provide food and nutrition security for low-income producers and consumers as they face the risks of climate change.