Page 15 - Vol.39-No.6

FISHERIES

TRACKING TUNA SIDE-STREAMS –

STEPS TOWARDS A MORE CIRCULAR

TUNA FARMING INDUSTRY IN MALTA

The PROFIUS project and its Malta-based preservation status prior to processing. To address challenges in the supply chain related
partner AquaBioTech Group (ABT) are making accomplish this, ABT researchers collected to lumpfish and tuna side-streams by devel-
significant advancements towards valorising tuna side-stream materials in Malta, placed oping preservation solutions for maintaining
previously discarded tuna side-stream ma- temperature probes inside the materials at the quality and improving utilization of the entire
terial and addressing logistic and technical moment of harvest, and logged the temper- biomass. The consortium involves different
challenges to transform these materials into ature of the samples as they travelled to the institutes such as Technical University of Den-
valuable products. shore and were frozen at -20 degrees Celsius. mark, the Norwegian University of Science and
The farming of Atlantic bluefin tuna (Thun- From harvest boat to on-land freezer, this Technology, and the University of Akureyri
nus thynnus) is a significant contributor to journey lasted between 3 to 6 hours. The re- working along with industries including Royal
the local economy in Malta. The Maltese tuna sulting temperature profiles from the duration Greenland, AquaBioTech Group (Malta) and
farming industry generated approximately 190 of the journey were used to evaluate potential BioPol (Iceland).
million euros in 2021, sustains nearly 1,000 histamine formation and spoilage through a
local full time employment opportunities, and predictive model developed by PROFIUS part-
provides a high-end fresh or frozen product for ner Technical University of Denmark (DTU).
markets in Japan and other regions across Asia. AquaBioTech Group also assessed the nu-
Although tuna aquaculture is a net positive for tritional properties and preservation quality of
the community, there is room for the industry the tuna side-stream materials to determine
to embrace sustainability and circular economy their suitability for the extraction of com-
approaches more fully, ultimately benefitting mercially relevant biochemicals. Collagen, en-
farmers and the environment. zymes, fish meal, and fish oil are all potential
In Malta, adult and juvenile wild bluefin by-products of the tuna farming industry and
tuna are caught offshore in the summer and can contribute to human health and the pro- Malta-based PROFIUS project partners
transferred to floating sea cages where they duction of feed for other aquaculture species. are currently investigating the potential
are intensively fed and grown to market size. General tuna side-stream preservation status for valorisation of tuna side-stream
Harvesting occurs from October to January was evaluated by the degree of oxidation, biomass.
in a process that generates by-product bio- and compositional analysis was performed to
mass. Whole fish are typically filleted on board investigate the nutritional properties of the
purpose-built vessels where prime cuts are side-streams. The results are promising, and
stored in freezers, and the product is then tuna side-stream material has been verified
directly shipped to the appropriate market. as a potentially highly valuable product.
Off-cuts including the head, tail, fins, viscera, As part of the PROFIUS project, ABT re-
and bone material have historically been dis- searchers are interested in the circular ap-
carded during the harvesting process. proach of extracting fish meal and fish oil
AquaBioTech Group, a private aquaculture, from local tuna side streams to incorporate
fisheries, biotechnology, and environmental into sustainable and functional aquafeeds. As
consultancy company, is making headway into a natural next step of the project, ABT will The main objective for PROFIUS in Malta
research that is necessary for tuna side-stream conduct tuna-incorporated feed trials with is to determine the suitability of tuna
product development. Researchers of the shrimp and European sea bass at their on- side-streams for use in aquafeeds. One
company hosted interviews with local stake- site recirculating wet lab facilities. These feed of the next steps for ABT researchers is
holders to identify which operational factors trials will allow researchers to determine the to conduct feed trials incorporating tuna
could limit the capacity for implementing cir- suitability of tuna fish oil and tuna fish meal fish meal and fish oil.
cular practices into daily harvesting activities. derived from side-streams as an alternative
The interviews highlighted that a lack of space protein source for aquaculture production.
onboard harvesting vessels for the storage Moreover, ABT scientists will also investigate
of side-streams is a major challenge. A sim- the capacity to improve the preservation sta-
ilar side-stream storage challenge was also tus of the side-stream materials using natural
raised for a local tuna processing facility. Due extracts. By doing so, the pre-processing time
to freezer space limitations, raw side-stream can potentially be extended under non-refrig-
biomass at the facility must be processed into erated conditions. Furthermore, ABT is also
fish meal and fish oil within 24 hours. If these in the process of collaborating with scientists
challenges are addressed, the tuna farming from the Norwegian University of Science and
industry in Malta will be able to generate more Technology to develop sustainable method-
opportunities for revenue, reduce waste, and ologies to extract valuable compounds from
reduce environmental impacts. the side-stream biomass. Tuna side-stream biomass is generated
PROFIUS is a three-year ERA-NET project during the harvesting and filleting pro-
To address these challenges, temperature
and chemical profiles of tuna side-stream unlocking the potential of aquatic bioresourc- cess. ABT researchers have conducted
materials were monitored to determine their es. It is a cooperation between Denmark, temperature and compositional analysis
Malta, Norway, Iceland, and Greenland to on locally sourced side-stream biomass.

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