Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 11:45:0020/09/2023 12:00:00Europe/ViennaAquaculture Europe 2023TECHNICAL, ECONOMIC and ENVIRONMENTAL ASSESSMENT OF BIOBASED AND BIODEGRADABLE ROPES (BIOGEARS) IN LONGLINE MUSSEL Mytilus galloprovincialis PRODUCTIONS: A SHIFT TOWARDS AQUACULTURE DECARBONIZATIONSchubert 4The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


L. A rantzamendi*, M. Andrés , Mª J. Suárez, A. Pocheville, L. Van der Schueren, J. Maher, M. Aguinaga

AZTI, Marine Research, Basque Research and Technolog y Alliance (BRTA).  Herrera Kaia. Portualdea z/g; 20110 Pasaia; Gipuzkoa, Spain



Low trophic aquaculture, such as bivalve species, can be candidate species for the minimization of environmental impact of worldwide growing aquaculture, while providing consumers with high quality and nutritive seafood. Nowadays, mussels are cultured suspended mainly in raft and longline systems, using ropes made of non-biodegradable fossil-based plastics , which use  could  result in  augmenting marine litter and microplastics entering the oceans .  The EU BIOGEARS project  addresses the challenge of minimizing the use of fossil -based  plastics by developing  alternative biobased and compostable ropes , biogears.  The aim of this study is to  assess  and compare  the  sustainability of  two biogears prototypes vs. commercial  fossil-based rope counterparts in  mussel  offshore  longline productions , under technical, economic and environmental perspectives.

 Material and methods

 Two biogears  ropes prototypes (B1 and B2)  were developed based on  compounds  of  commercially available biopolymers and manufactured with industrial processes to be fit-for-purpose , with technical and mechanical properties similar to commercial counterparts, for mussel productions .  For the technical assessment , the  upscaling of their potential implementation by minimizing technical risks at  rope  production and  the  aquaculture performance phases  were studied.  For  aquaculture  validation, a  one-year mussel longline production  was performed using biobased B1 and B2 ropes and commercial fossil-based rope counterparts (GROPE).  In the economic assessment,  the costs and benefits of the use of biogears in mussel aquaculture were analysed  along the value chain , comparing them to fossil-based ropes ( market trends of  raw materials, rope processing costs, aquaculture production, and End of Life (EoL) options).  Additionally, the eco-efficiency indicator of  the ropes was calculated (ISO 14045:2012) .  In the environmental assessment, rope  biodegradation trials and the  environmental profile  via Life Cycle Analysis (LCA) methodology (ISO 14040/14044 ) were studied.

Technical assessment : Biobased ropes  promoted  similar mussel growth but  higher mussel productions per rope linear meter ( 85%  in  B2 and 23%  in B1) with respect to the fossil-based  rope counterpart (4.29 kg/m). Overall, mussel a bundance  per rope linear meter decreased over the experimental period in all types of rope ,  and especially in fossil-based ropes . Mussel quality was not compromised by using biobased ropes , as similar Condition Index, meat yield,  proximal composition and fatty acid profiles  were observed  among  experimental groups. Mechanical properties (Load at Break and elongation)  of biogears  decreased in the first two months of the sea tests, although not compromising rope functionality in  one-year mussel production. T he correlation between total mussel weight held per rope and the Load at Break results demonstrated that a 40% higher mussel weight held by B2 ropes had no significant effect on the variation of their mechanical properties.

Economic assessment :  Currently, the raw materials used in biogears are economically more costly than the raw materials of  fossil-based counterparts. Future trends  envisage increasing biopolymer production s to meet market demand, which could in turn  reduce their price  and make  biogears even more competitive than fossil-based ropes.  Mussel productivity gains in  biobased B2 ropes offset the over-cost of the biogears production, making mussel production more profitable with biogears than with the commercial fossil-based ropes. B2 prototype rope production and use should be encouraged, rather than biobased B1 and fossil-based ropes, due to their best eco-efficiency indicator (environmental impact and economic value of the ropes by kilogram of harvested mussel) (Figure 1).

Environmental assessment : B iodegradability  tests in marine conditions indicate that biogears will not biodegrade in sea water at 20-30 °C or below. Compostability tests  simulated in laboratory conditions  (58±2 ºC) concluded that  industrial composting  of biogears is technically feasible . However, i t should be validated in industrial  composting facilities.  Composting, as EoL option for biobased ropes, w ould reduce by 10% the carbon footprint of their life cycle and the impact on the use of fossil resources, due to the benefits of avoided impact s and the  use  of the produced compost . So, actions for the c ollection, sorting and transport  of biogears  to industrial composting facilities are encouraged for a correct management  at their EoL .  Finally, considering rope aquaculture production (impact/kg mussels produced per rope linear meter), B2 rope shows the best environmental performance, reducing by 34% the carbon footprint of mussel productions compared to conventional fossil-based ropes.

It can be concluded that biogears , and specifically biobased B2 ropes , can be technical, economic and environmentally sustainable alternatives to currently used fossil-based ropes in mussel offshore productions promoting aquaculture decarbonization. 

BIOGEARS is supported by funding from the EU European Maritime and Fisheries Fund (EMFF).