Publication - Research and analysis

MGSA Science & Research Working Group - Aquaculture Science & Research Strategy

Published: 15 Jul 2014
Part of:
Marine and fisheries
ISBN:
9781784126636

MGSA S&RWG was tasked to produce a comprehensive research strategy prioritised on respective contribution to informing the sustainable growth of the Scottish aquaculture industry and potential impacts of the 2020 sustainable production targets as detailed

143 page PDF

2.6 MB

143 page PDF

2.6 MB

Contents
MGSA Science & Research Working Group - Aquaculture Science & Research Strategy
05 Table Technology & Engineering

143 page PDF

2.6 MB

05 Table Technology & Engineering

General Topic
Priority Ranking (1-8)

Objectives

Relevance to 2020 target

Potential deficiencies in Infrastructure/Resource Requirements

1) Non-chemical treatment of sea lice

(1) To investigate non-intrusive methods of counting (see Topic 3 also) and removing sea lice on affected finfish. Optical delousing has been investigated in Norway [1], [2], using short burst lasers but the practicality of this technique for full scale conditions has not been demonstrated. This technique should be investigated further, as should the use of light (and/or colour, motion and chemicals) as an attractant to trap sea lice (presently being investigated in Canada [3] ).

(2) To investigate through feasibility studies and consultation the use of acoustic and electric field methods to delouse finfish. Such methods have advanced considerably in recent years (particularly in the field of imaging) and they offer, in principle, advantages of being non-intrusive and durable.

(3) To investigate improvements in methods of mechanical removal of lice (including the use of thermal methods [4] ) that minimise stress and overcome deficiencies in filtering of stripped lice due to requirement of large volumes of water and insufficiently fine filters to retain egg strings and lice.

(4) To investigate design innovations to nets and cages to prevent ingress of sealice, including those presently under investigation in Norway [5], [6] using plankton nets, lice skirts, underwater feeding, snorkels, electric fields.

Significant reduction in losses of fish to sea lice infestation and resultant increases in fish health, without recourse to expensive or ineffective chemical treatments, is essential if the industry is (i) to achieve the 2020 targets in increased finfish production and (ii) to do so in a sustainable manner without damage to the marine environment.

Many non-chemical methods of removing lice from fish or preventing the attachment of lice to the fish are already being pursued within the industry or at a pilot laboratory scale, albeit at an early stage.

There is scepticism within the industry over the practicability of some of the innovations proposed or being investigated and some of the suggested techniques ( e.g. acoustic and electric fields techniques) have not been tried yet or the results of early tests are not clear or unavailable.

A great opportunity exists to collaborate with Norwegian researchers in this area. Much of the key innovative work on non-chemical removal and treatment of sea lice is underway in Norway [4], [5], [6], [7], even at an early stage. Agreement has been reached to enhance joint working and information sharing under the Scotland-Norway MoU on aquaculture that helps bring both countries up-to-date with current industry developments and enables the further sustainable growth of Scottish salmon farming to achieve 2020 targets [8] . Of relevance to this Task Force is the agreement to collaborate on (i) tackling sea lice and (ii) improving containment to reduce escapes.

HIGH PRIORITY

2) Anchors & Moorings

(1) Define hydrodynamic loading regime on pen/mooring line systems for future exposed offshore locations and the resulting mudline loads that the anchors must support [9] , [10]. This should include study of increases in these loads due to subsequent fouling [9] .

(2) Reduce seabed footprint of moorings [10] . Use of taut line rather than catenary moorings allows potential for vertical mooring lines (tension leg arrangement). This would include potential for anchor sharing to improve efficiencies while avoiding progressive failure. This will maximise density of production for a given site and reduce damage to seabed environment from chain scour.

(3) Develop new, more efficient anchoring systems [10] . Design of taut leg moorings from Obj. 2 is controlled by anchor capacity [11] . Anchor efficiency defined in terms of: static holding capacity per unit dry anchor weight, resistance to cyclic loading, cheaper/quicker/more efficient installation [9] , no requirement for specialist vessels. Such anchors will need to perform closer to their limiting states ( i.e. at lower factors of safety), requiring more accurate loading information from Obj. 1. Moorings and anchors to be considered as a combined system, e.g. use of elastic dampers [12], [13] in the lines could be used to reduce line tensions and therefore allow smaller anchors due to reduced mudline loads.

(4) Development of aquaculture specific engineering standards [10] . Required to support design of moorings/anchors (and cages) in exposed locations (offshore). To incorporate guidance based on Obj. 1 and be applicable to systems developed in Obj. 2 & 3.

Subject to other biological, environmental and regulatory considerations, anchoring and mooring is a key technical hurdle to allowing expansion into offshore/exposed locations to significantly increase production (see Topic 6). Use of such locations also opens possibilities for co-locating with other offshore facilities (renewables/oil & gas).

Reduction in footprint & use of efficient anchors additionally allows greater density of production in inshore/existing sites.

Improvements in moorings and anchors [14] will contribute to improvements in containment, with resulting increases in production.

(1) Little/no field or tank test data on mooring line forces or mudline (anchor) loads for aquaculture-specific problems; Potential for use of existing modelling infrastructure used for offshore renewables (wave tanks etc.). HIGH PRIORITY

(2-4) Transfer potential of technology from offshore oil & gas industry [11], [15] is high, but has hugely different design requirements (fewer, larger over-designed anchors). Fundamental development and validation of new design methodologies required for more efficient use in aquaculture.

MEDIUM-HIGH PRIORITY

3) Sensors, automatic monitoring and intelligent systems

(1) Undertake survey of manually intensive work in aquaculture work-tasks ( e.g. cleaning, feeding, sampling of stock) to determine those which show opportunities for automation. Many of the sensors required are already in commercial production. Others are at various stages of TRL (technology readiness level). Many sensors are physically large (esp. chemical sensors) and could be miniaturised to good effect.

(2) Develop a vision of an aquaculture facility that uses a range of sensors for monitoring various parameters, under computer control. Parameters could include water quality (dissolved oxygen, pH, conductivity, ORP (oxidation/reduction potential), TDS (total dissolved solids), turbidity, salinity, temperature, prescribed chemicals), meteorological/marine properties (currents, waves), mooring behaviour/performance, net tension and net deformation. ( EU Project WARMER [16] demonstrated progress with chemical sensors, networking, satellite/in-situ data integration for estuaries, inland water bodies). Intelligent mooring sensor systems could sense changing weather and sea conditions and control moorings automatically. Data sent by wireless communications to the base station, where software measures, correlates and interprets trends in the data. Robotic machines could be used for various manually- intensive tasks.

(3) Develop sensors for monitoring of fish feeding and behaviour (fish weight, quality, condition, mortality, net condition, optical/thermal imaging, fish health monitoring and miniaturised devices attached to fish [17] (measure temperature, pressure, physiological parameters, speed).

(4) Investigate sensor networks and communications. Wireless Sensor Networking is developing rapidly; many aspects of the technology could be adapted for underwater networks. So there could be an array of sensors, networked together wirelessly. The array gives fault tolerance and resilience, dynamic re-configurability and the ability to make correlated sets of measurements. Low power consumption is achieved through: low-power hardware, software (controlling processor sleep modes), optimised communication protocols. Energy scavenging ( e.g. light, vibration). Wireless communications offered by (i) mobile phones, 2.9 GHz standards, various serial telemetry options, SatCom, etc. and (ii) WSN technologies, IEEE 802.15.4, above water, under water, RF, acoustic.

(5) Investigate standards: There is a need to make sensors plug and play, with standard interfaces. Hardware interface standards: IEEE1451, I2C, 1-Wire. Software standards: Open Geospatial Consortium Sensor Web Enablement. Permits sensors to be part of the Internet of Things. OGC SWE includes Sensor ML (MarkupLanguage), Transducer ML, Sensor Observation Service, Sensor Planning Service, etc..

(6) Exploitation of computer vision has been applied experimentally to a range of monitoring tasks, and in some cases has resulted in commercially available devices. Opportunities are (i) counting (eggs, larvae, fry, fish), Dimensions and shape of fish (sometimes using stereo camera pair), hence mass, (ii) gender identification, (iii) quality assessment - mainly with dead fish, but there have been a few trials with live fish (mainly colour, gender and sizing), (iv) species & stock identification, (v) monitoring fish behaviour and (vi) monitoring fish welfare. Little has been done so far on sea lice detection and counting by computer vision; difficulties arise due to the relatively small size: <1mm (juvenile), up to 5 (male) or 10 mm (female) adults. Could CV be used for automated monitoring of fouling?

Incorporation of sensors into aquaculture operations has been recognised by industry [14] as offering opportunities to monitor fish health more efficiently than at present, contributing to the increased production required by 2020 targets.

Satisfying such 2020 targets depends on improving containment; deployment of sensors to monitor automatically the nets, cages, fish and water conditions, together with the development of associated control systems, provides an important contribution to prevent escapes, particularly when aquaculture installations are unattended.

In the general sensor market, over the last 5-10 years there has been an explosion in the number of devices. Market growth is driven by lower cost and lower power (of sensors themselves and the associated microelectronics), chip-level integration ( e.g. lab on a chip technology) and increasing availability of wireless connectivity.

With fish farms growing in size and number and with their imminent move further offshore, there is a growing need to automate much aquaculture. There is a need for water quality monitoring in real time to feed into estimates of carrying capacity of coastal waters.

Comparisons should be made with 'The field of the future', in which the Oil & Gas industry is forward looking (5-10 years) to plan for extensive automation, remote working, and communications (largely wireless). The aquaculture industry could do likewise - 'The farm of the future'.

HIGH PRIORITY

4) Anti-predator developments

(1) Development of 'burglar alarm'-type intelligent systems that initiate sound when fish panic detected [18] .

(2) Investigate use of other anti-predator (seal) techniques (non-acoustic?), including (i) electric field deterrents [19], [20], (ii) robotic deterrent devices operating outside nets.

3) Investigate structural analysis of net design [21], [23], [24] and automated net tension devices to determine optimal tension to prevent seal exerting pressure on slack net to obtain fish. Include investigations of smart designs of nets to detect holes and activate self-sealing measures [10] .

(4) Investigate the benefits and disadvantages of using predator nets [25] , including considerations of hydrodynamic drag.

Predator behaviour (in particular seal attacks) remains an important threat to containment and thereby is a significant consideration in assessing the industry's capability to attain 2020 increases in finfish production.

Though the effective deterrence and control of seals remains an important concern, there is evidence from within the industry that the number of seals being shot has decreased significantly and that bigger, tenser nets help (as does removal of dead fish) in this regard. Intelligent 'burglar alarm'-type systems [18] for seal scaring are on the market but there are opportunities for further research in this.

Deterrence and control of predators by non-acoustic methods are attractive, not least because of the need to overcome seal familiarity and adjusted behaviour with present scarer systems.

MEDIUM PRIORITY

5) Location to open water sites

(1) To intensify reviews of all engineering and technological aspects of location to 'more exposed'/'less sheltered', 'open water' sites [10], [26]. There is a view within the industry that such location will present sets of problems that need to be tackled primarily by engineering solutions. The types of engineering problems of relevance here are associated primarily with the hostile wave climates [27] in which the open water farms are to be situated and the upscaling in spatial extent of the farms. These factors have consequences for the design of (i) innovative moorings and anchors matching the local ground conditions and achieving reduced plan area, (ii) large, accessible feeding structures (and perhaps accommodation structures) and (iii) submerged cages.

(2) To re-visit and improve the hydrodynamic dispersion models [28] (particle tracking) and AUTODEPOMOD regulatory software packages [29], [30] presently in use in UK industry for predicting the fate of waste from cages. Such models and software packages are currently suited to sheltered sites. Improved models are required in order to obtain predictive estimates of the fate of waste materials and the environmental impact of large installations in water conditions dominated by wave forcing.

Strategic considerations of moving aquaculture production to open sea sites are associated with the horizon beyond 2020 though there are implications for 2020 targets.

Open water aquaculture developments are inevitably linked to issues of co-location (Topic 6) and to the improvements needed for moorings and anchors (Topic 2).

Work is already underway ( SARF Project SARFSP009 - Technology for the Development of Aquaculture in More Exposed Locations in Scotland) within the industry to look comprehensively at strategic issues associated with expansion of the industry to open water locations. This industry-led project will provide (in late 2014) important guidance on technology, engineering and management research requirements associated with open water aquaculture.

In addition, experience from existing and planned aquaculture installations in UK waters [31] will inform strategic plans involving engineering and technology innovation development.

HIGH-MEDIUM PRIORITY

6) Co-location with and multi-use of existing and new marine structures

(1) Identify matches between requirements of energy converters and species. Promising initial results have been achieved through use of shallow water blue mussels within a shallow water wind farm at North Hoyle [32] . However, even in these shallow conditions, the currents were challenging for the mussels. As the Scottish marine environment is more extreme, the limits of endurance of proposed species should be evaluated in order to provide better focus for proposed pairings. This should be extended beyond shellfish. General approaches using criteria scoring matrices have been adopted for similar studies elsewhere [33], [34], and whilst this may be helpful to begin with, it would be anticipated that these need supporting scientific evidence to ensure confidence.

(2) Commercial scale field trials. The conclusions of the North Hoyle work, and the subsequent report to the Shellfish Association of Great Britain [32] , identified a tentative success with the need to adopt a larger scale field trial.

(3) Scottish environment, shallow water: Partnership strategy for integrating aquaculture into offshore energy farms. The output of Obj. 1 is to identify species that may be suitably cultivated in the environments into which renewable energy farms are located. Whilst the EU projects [34] are focussing on new structure design, many of the energy installations around Scotland are already sufficiently advanced in the planning that a redesign to accommodate aquaculture is unlikely. Therefore, this project must identify how the species identified in Obj. 1 may be suitably integrated into the existing fields. This requires consideration of the aquaculture science, the legal and logistic framework for ownership and operation, and the structural integrity under these new, non-designed loading.

(4) A modular platform suitable for use in the Scottish environment: deep water. The shallow water/near shore cultivation of shellfish is promising, but with offshore energy being increasingly driven into deeper waters and into open ocean, there exists significant scope for a different combination of activities. These deeper water solutions would require significant improvement in current engineering knowledge of the structural and foundation design, and as such projects are not at an engineering planning stage then a novel platform design may be considered. This would require a significant amount of interaction between engineers (electrical and civil), marine scientists and potential stakeholders in order to achieve a priority-balanced design and accompanying usage guidelines.

The crowding of the marine environment is a key theme for future planning [33], [36], [37], [38] and by investing over 10M euros in multiple research projects, the EU have clearly prioritised this too.

The 2020 target is to increase shellfish production (especially mussels) significantly. Co-location offers opportunities to contribute to this increase in production.

For Offshore Renewable installations ( ORIs), the co-location of aquaculture activity offers opportunities (i) to use aquaculture production to offset the loss of commercial fishing within the exclusion zone around the ORI and (ii) to provide a zone within which commercial fish and shellfish can recover from overfishing. This contributes to the sustainability objectives within the 2020 targets.

Co-location will demonstrate good custodianship of the zone and provide nutrients to restore indigenous shellfish populations and increase productivity (scallops).

Co-location is relevant also to Scotland's first National Marine Plan [39] which will provide a single framework to manage all activity in Scottish waters and guide development of a sustainable and successful offshore renewable energy industry.

(1) There are probably sufficient data available for high-level consideration of species suitability. Some further exploration may be necessary for more detailed consideration of the most promising activities.

HIGH PRIORITY

(2) Few options for undertaking large-scale co-location trials in suitable conditions.

MEDIUM PRIORITY

(3) An appropriate selection of species on which to concentrate is required (Obj. 1) as well as an initiation of debate between stakeholders to identify barriers to success in Scottish waters.

MEDIUM-HIGH PRIORITY

(4) There are many uncertainties in all areas of deeper water offshore energy even without considering the additional shared-use element. As such, this remains a long-term goal, although one for which debate should be initiated now.

LOW-MEDIUM PRIORITY

7) Seaweed and algae cultivation

The key engineering challenges of seaweed (macroalgae) aquaculture in coastal and/or open-sea areas relate to cultivation of seaweeds at special 'farms', seaweed harvesting, and transportation [40], [41]. Among them, the knowledge base, underpinning the design of optimal cultivation devices/structures, is the weakest point of seaweed aquaculture engineering and technology. To develop optimal seaweed growth structures that maximise the rate of biomass production and minimise adverse deployment effects ( e.g. instability/destruction at high waves/flow velocities) at given hydrodynamic conditions, nutrient supply, and sea-bed composition, the following research objectives are to be achieved:

(1) To identify key mechanisms and develop process-based models of seaweed growth and interactions between seaweed farms and combined wave-current environments at all relevant scales (from blade to patch (unit) to the whole farm), including effects of drag forces, mass-transfer processes, and light attenuation.

(2) To develop optimal mooring/anchoring structures, specific to seaweed farms, for a range of typical sea-bed conditions (also as a part of the Anchors, Moorings, Foundations topic above).

(3) To identify key mechanisms and develop modelling capabilities for assessing the multi-scale effects of seaweed farms on the marine environment, particularly associated with effects on wave climate, water currents, sea surface roughness, nutrient depletion, and sea-bed (also as a part of the topic Improved Hydrodynamic Modelling above).

(4) To perform multi-scale pilot deployments to provide data for testing research findings and inform Strategic Environmental Assessment and the development of appropriate Environmental Impact Assessment methods and thresholds.

The research priorities related to biological and biochemical aspects of seaweed farming are outlined in the section Marine/Blue Technology.

The developed knowledge will underpin both optimal seaweed farming as a stand-alone operation and integration of seaweed aquaculture into larger-scale operations involving multiple users of marine resources. This later aspect highlights direct potential contribution to achieving the Scottish Government targets in relation to finfish and shellfish production. Indeed, seaweed operations, as part of the Integrated Multitrophic Aquaculture ( IMTA), may significantly enhance sustainability of fish and shellfish farming and minimise their environmental impacts [40] .

Currently available engineering solutions in seaweed aquaculture world-wide are largely empirical [42], [43] and thus with high level of uncertainties in relation to the structure stability, biomass growth rate, and environmental impacts. The specialised modelling tools are practically absent making any optimal design and operational predictions for particular environmental conditions unrealistic.

MEDIUM-HIGH PRIORITY

8) Closed containment

Application of closed containment technology in the form of either land-based Recirculating Aquaculture Systems ( RAS) or Floating Closed Containment ( FCC) systems represents a potential route for expanding Scottish salmon growout production. Recent international developments have seen increasing interest in completing the production growout cycle to harvest weight or rearing Atlantic salmon to an interim weight, 600 to 1,000 grams, before transfer into seawater pens. (Current Scottish RAS expertise is directed towards early-age culture, smoltification and holding broodstock).

Key challenges in adoption of closed containment technology by the industry are both biological and engineering, together with the comparatively high level of initial capital investment required for an on-land RAS system and building confidence through increasing operational predictability/repeatability and standardising solutions. Research objectives:

(1) To undertake an economic assessment and evaluation of the development of potential revenue generation streams from RAS waste. Options should include aquaponics, algae biomass production and anaerobic digesters. HIGH PRIORITY

(2) To determine the optimal rearing conditions (temperature/salinity/stocking density) re welfare & growth rate when cultured at high densities in RAS systems for Scottish strains of Atlantic salmon. HIGH PRIORITY

(3) To evaluate technological solutions for capturing and thickening waste, e.g. polymer technology, de-salting marine sludge. MEDIUM PRIORITY

(4) To research technologies to deliver energy efficiencies including: low energy/low head gas control systems; application of constant flow technology pump; and combining processes/units, e.g. pumping and oxygenation. MEDIUM PRIORITY

(5) To investigate emerging technology solutions to achieving enhanced water quality including: improving removal of organic matter before it enters the biofilters; use of denitrification reactors and use of use of Anammox systems. MEDIUM PRIORITY

If the research indicates that adoption could be sustainably viable then adoption would provide the potential for shortening the seawater production phase in Scotland, enable the industry to increase its overall production in existing coastal locations and thereby contribute to the industry's strategic growth plan, and in addition would provide the prospect for reducing interactions with populations of wild migratory salmonids.

Work is already underway modelling of the potential for shortening the pen-based phase of the salmon ongrowing Cycle, ( SARF Project SP008). However there is scepticism within the industry over the potential adoption of closed containment technology, particularly on-land RAS, to complete the growout cycle and deliver commercially viable Atlantic salmon. A great opportunity currently exists to collaborate with Norwegian, and North American researchers in this area and economically efficient high value research.

MEDIUM-HIGH PRIORITY


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