Binder seeding to improve the economic case of UK macroalgal cultivation (Bindweed)

The emergence of macroalgal cultivation as an aquaculture industry in the UK lags behind many of our neighbours such as Norway, France, Spain and Ireland. Cultivation of macroalgae for food products is profitable and there exists a large unmet market potential, both within the UK and across Europe. Currently, the industry is limited to small-scale cultivators due to the large manual requirement for activities such as outplanting of seedstock. The project Bindweed aims to translate and refine recent research into an innovative new technology that will substantially reduce the cost of macroalgal outplanting for end-users.

The current state of the art involves manually winding twine carrying hatchery reared juveniles around longline ropes. The Bindweed method, embeds juvenile macroalgae within a hydrocolloid matrix which can then be directly applied onto cultivation substrates. Juveniles which would traditionally be maintained in the hatchery for several weeks are held in the binder matrix for long enough to allow attachment directly to the substrate before the binder degrades. The Bindweed method is expected to a) increase the space-efficiency of hatchery cultivation 100 times, b) increase the speed of deployment by at least 3 times and c) could be mechanised/automated for use at larger scales further increasing efficiency. In academic trials, the binder method produces a comparable or higher yield of macroalgae than twine, yet the binder method is unreliable. Success of the binder method appears to be related to the physicochemical conditions during initial outplanting, most notably water motion created by waves and/or tides. In the current formulation, shear from high water motion results in the degradation of the binder before the juveniles are able to attach, causing crop failures or reduced seeding densities.

The Bindweed project will address the current unreliability through four inter-connected work packages (WP) which will develop the binder from Technological Readiness level 6 to 8 by combining laboratory testing, field monitoring and field experimentation to inform a final economic assessment.

WP1 will optimise the binder/material /flow interaction through replicated trials within a controlled flow environment (biological flume). New binder formulations (composition, viscosity and thickness) will be challenged with different flow regimes and combined with novel cultivation substrates aimed at improving retention of juvenile plants.

The selection of the flow regimes trailed within flume studies will be informed by environmental monitoring at four macroalgal cultivation sites with different influences of tidal and wave driven flow in WP2. The flow environment within the surface layers (suitable for cultivation) will be characterised in detail to address limitations in traditional monitoring and modelling tools used to assess site suitability for cultivation projects. Surface flow measurements, along with other measured physicochemical conditions including light, temperature, nutrients, pH, and dissolved oxygen will be used to support existing modelling tools to better inform the site selection process.

In WP3, outplanting trials at the four cultivation sites will be used to confirm the suitability of the proposed optimised binder formulation and substrate (from WP1) in the real-world. Outplanting success and growth rates will be monitored in parallel with WP3.

In WP4, an economic analysis will compare the binder seeding innovation compared to the standard twine seeding method to demonstrate the tangible economic benefits of the project created through the fusion of academic and industrial knowledge. This will be combined with a SWOT analysis, to create a decision tool for UK cultivators.

The emergence of macroalgal cultivation as an aquaculture industry in the UK lags behind many of our European neighbours such as Norway, France, Spain and Ireland. The project Bindweed aims to translate and refine recent research into an innovative new technology that will substantially reduce the cost of macroalgal out-planting for end-users: The current state of the art involves manually winding twine carrying hatchery reared juveniles around longline ropes. The Bindweed method, embeds juvenile macroalgae within a fibrous hydrocolloid matrix which is then mechanically applied to cultivation substrates. Juveniles which would traditionally be maintained in the hatchery for several weeks before out-planting are held in the binder matrix at sea to allow attachment directly to the substrate. In academic trials, the binder method produces a comparable or higher yield of macroalgae than twine, yet in its current formulation the binder method is unreliable due to its susceptibility to water motion created by waves and/or tides in surface waters necessary for cultivating macroalgae.

The Bindweed project will address the current unreliability through four inter-connected work packages. Laboratory flume trials will test several new binder and material formulations to optimise the binder/material/flow interaction for improved seeding success (WP1). The flow characteristics at four cultivation sites will be measured alongside other physiochemical properties to address limitations in traditional monitoring and modelling tools used to assess site suitability for cultivation projects (WP2). Outplanting trials at all four sites will be used to confirm the suitability of the proposed optimised binder formulation and substrate in the real-world (WP3). An economic analysis will compare the binder seeding innovation to the standard twine seeding method to demonstrate the tangible economic benefits of the project created through the fusion of academic and industrial knowledge (WP4).

The successful development of the Bindweed methodology for seeding kelp macroalgae will greatly advance the economic case for macroalgal cultivation in the UK by reducing costs and increasing the automation potential of outplanting. This will be an immediate boon for kelp cultivation companies with the UK and Europe. These companies will be able to apply this technology to decrease their farm gate price, leading to increased profitability and competitiveness in the market.

Bindweed will increase the reliability and simplicity of cultivation methods used by macroalgal cultivators. These improvements will reduce the risk and increase the rate of return on financial investment. This will allow European cultivators to more easily gain loans or investment and encourage the expansion towards widespread macroalgal cultivation across Europe; also potentially re-investing into further innovation. These benefits will not only apply to macroalgal cultivation for food, but to other Blue Bio-economies including cultivation for the extraction of high value products including pigments, health supplements or bioactives.

Bindweed will affect the decision making of UK cultivators, making them more aware of how outplanting success is influenced by climatic fluctuations. This will increase the reliability of outplanting and help to mitigate business risk, allowing greater confidence in yield predictions. This information will also be relevant for future business planning, regarding how climate changes will lead to increase storminess, which may have negative impacts, or change the method used for

The binder seeding method may also be directly applicable, or adaptable, for use with other macroalgal species worldwide. Currently, kelp cultivation in SE Asia counts for a third of the global macroalgal production (8 million ton in 2012). The innovation may also lead to increased automation of outplanting for cultivation of numerous species.

By increasing the profitability of macroalgal cultivation, the innovation may encourage the uptake and investment in integrated multi-trophic aquaculture (IMTA) by existing aquaculture companies in the UK such as salmon producers e.g. Marine Harvest. As extractive organisms, macroalgal cultivation will improve the environmental credentials of fish aquaculture, whilst products marketed from IMTA can attract a higher premium from consumers. Additionally, this will also provide trophic economic diversification, into a product whose price is not correlated with fish.

An increased uptake of macroalgal cultivation in the UK will benefit rural coastal communities by developing a new industry that will bring with it employment opportunities. This will help to reduce depopulation of these areas and encourage more talent young adults to remain in coastal communities.

One of SAMS' goals is to enthuse the next generation of marine researchers by promoting and advertising high quality science which improves our understanding of the natural world around us. Seaweed cultivation is evocative, capturing the public's attention and Bindweed may encourage both entrepreneurship and entry into research. Throughout our impact activities we will reinforce macroalgal cultivation as an environmentally and economically sustainable activity and increase awareness of macroalgal and aquaculture research.