Framework for Autonomous Navigation for a Permanent Resident Aquaculture Net Grooming Robot

This paper proposes methods to enable autonomous operation, specifically for localization and motion planning, of net grooming robots in aquaculture net pens and validates the proposed methods in both simulations and experimental fieldwork. Moreover, this paper suggests enabling uninterrupted operation by investigating the use of data from an inertial measurements unit that is a common sensor in underwater vehicles, rather than investing and upgrading to costly sensory systems that often require additional installation and calibration. In particular, the presented work consists of a localization method capable of estimating a robotic system's cylindrical position in an aquaculture net pen, a 3~DOF cylindrical robotic model, a method for path planning and collision avoidance, and a heading guidance and control system. The simulations demonstrate successful localization of the robotic system, while simultaneously planning and following collision-free trajectories in an environment obstructed by obstacles. Furthermore, the field trials successfully demonstrate that the system, when applied to net crawling robots, is capable of localization, path planning, and collision avoidance in an aquaculture setting. As follows, the presented work contributes to establishing net grooming robots as competitive candidates for biofouling management.acceptedVersio

Under the sea: How can we use heart rate and accelerometers to remotely assess fish welfare in salmon aquaculture?

Recent advances in bio-sensing technologies open for new possibilities to monitor and safeguard the welfare of fishes in aquaculture. Yet before taken into practice, the applicability of all novel biosensors must be validated, and the breadth of their potential uses must be investigated. Here, we investigated how ECG and accelerometryderived parameters measured using bio-loggers, such as heart rate, acceleration and variance of acceleration, relate to O2 consumption rate (MO2) and blood borne indicators of stress and tissue damage to determine how biologgers may be used to estimate stress and welfare. To do this, we instrumented 13 fish with a biologger and an intravascular catheter and subjected them to a swimming protocol followed by a stress protocol throughout which the physiological parameters were measured and analyzed a posteriori. Additionally, based on the empirical data obtained, we calculated the mathematical relationships between the bio-logger data and the other parameters and tested the relationship between the calculated parameters using the linear regression algorithms and the measured parameters. Our results show that acceleration is a good proxy for swimming activity as it is closely related to tail beat frequency. In addition, we show that heart rate, acceleration and variance of acceleration all can be used as predictors for metabolic rate. Accelerometry based data, especially variance of acceleration, significantly explain some of the variation in venous partial pressure of O2, blood lactate and plasma cortisol concentration. Variance of acceleration also significantly explains some of the variation in pH and mean corpuscular hemoglobin concentration. These relationships are explained by variance of acceleration being a good indicator of the onset of burst-swimming activity, which is often followed by acid-base imbalances and release of catecholamines. The results herein indicate that bio-logger data can be used to extrapolate a range of stress-related physiological events when these are accompanied by increases in activity and highlight the great potential of biosensors for monitoring fish welfare. Biologger Acceleration Heart rate Stress MetabolismpublishedVersio

Towards cost‐effective biofouling management in salmon aquaculture: a strategic outlook

Biofouling is an ongoing challenge for marine salmon aquaculture, impacting farming operations, fish health and welfare. Current mitigation strategies employed in Norway and Scotland rely mainly on the use of antifouling coatings and reactive removal of biofouling. These approaches are not only costly and of limited efficacy, but also pose active risks and likely contribute to mortality of fish during grow-out at sea. Given the inefficiencies of current biofouling management approaches and the industry’s objectives for growth and sustainability, a strategic assessment of future avenues for biofouling management is needed. We here present such an assessment and outline three novel biofouling management strategies that, once implemented, could facilitate improved fish health and welfare, reduced environmental impacts and benefits to the public perception of fish farming. These strategies are based on: (i) efficient antifouling coatings; (ii) antifouling combined with intermittent cleaning; and (iii) grooming of nets. We discuss the advantages, challenges and research and development needs associated with the realisation of these strategies. Drawing on experiences from agricultural systems and invasive species management, we show how the costs involved in the implementation of new strategies will over time be offset by the direct and indirect benefits arising from a reduction in environmental and fish health impacts and an increase in the industry’s social licence to operate.publishedVersio

Efficacy testing of novel antifouling systems for marine sensors

Marine sensors are widely employed tools for remotely providing a representation of their environment. The primary factor limiting measurement accuracy and deployment longevity is biofouling. For prevention, copper is the most widely applied biocide, often in form of adhesive copper tapes. However, for complex shapes these tapes are challenging to apply. Furthermore, sensor operating life frequently exceeds the antifouling protective period of the tape and the exchange of antifouling systems can be prohibitively time consuming and expensive. Alternative antifouling systems are needed to improve the cost-effectiveness of marine monitoring. This study tested a novel adhesive antifouling film based on copper cold spray technology in two concentrations (586 g m−2 and 306 g m−2) against a commercial copper tape (367 g m−2) and an uncoated control. After ten months of immersion, the lower concentration adhesive film performed equal to the commercial copper tape while achieving higher durability and better leaching control. In contrast, the antifouling performance of the high-concentration film was at times lower than that of the commercial copper tape, likely due to high embedment depth of copper particles. Customizable, cold spray metallised adhesive films may offer an advantage compared to ‘traditional’ tapes, including the potential to reduce copper emissions.publishedVersio

Seatonomy applied in operational analysis of an autonomous net cleaning robot - NetClean 24/7 report for work package H1.1: Operational analysis and overall system design

This report presents an analysis of the autonomous cleaning operations handled in the NetClean 24/7 project. The analysis was conducted using the Autonomous Job Analysis (AJA) concept introduced in the Seatonomy method. This includes the identification of the autonomous capabilities that a tetherless cleaning robot needs to conduct simultaneous net cleaning and inspection, as well as system design requirements and specifications related to equipment, sensors, actuators, architecture, error management and safe modes.Seatonomy applied in operational analysis of an autonomous net cleaning robot - NetClean 24/7 report for work package H1.1: Operational analysis and overall system designpublishedVersio

Towards cost‐effective biofouling management in salmon aquaculture: a strategic outlook

Biofouling is an ongoing challenge for marine salmon aquaculture, impacting farming operations, fish health and welfare. Current mitigation strategies employed in Norway and Scotland rely mainly on the use of antifouling coatings and reactive removal of biofouling. These approaches are not only costly and of limited efficacy, but also pose active risks and likely contribute to mortality of fish during grow-out at sea. Given the inefficiencies of current biofouling management approaches and the industry’s objectives for growth and sustainability, a strategic assessment of future avenues for biofouling management is needed. We here present such an assessment and outline three novel biofouling management strategies that, once implemented, could facilitate improved fish health and welfare, reduced environmental impacts and benefits to the public perception of fish farming. These strategies are based on: (i) efficient antifouling coatings; (ii) antifouling combined with intermittent cleaning; and (iii) grooming of nets. We discuss the advantages, challenges and research and development needs associated with the realisation of these strategies. Drawing on experiences from agricultural systems and invasive species management, we show how the costs involved in the implementation of new strategies will over time be offset by the direct and indirect benefits arising from a reduction in environmental and fish health impacts and an increase in the industry’s social licence to operate

Efficacy testing of novel antifouling coatings for pen nets in aquaculture: How good are alternatives to traditional copper coatings?

Biofouling is a challenge in global sea-based salmon farming. Norway's salmon-growing industry relies primarily on copper-based antifouling coatings. However, copper is an increasingly recognised environmental hazard, and there is a need to develop alternative antifouling products to prevent biofouling in marine aquaculture. Using field experiments, this study compared the efficacy of six novel antifouling coatings for fish farm nets (two with reduced copper content, three with alternative biocides and one biocide-free coating) against a popular commercial copper coating and uncoated samples. The performance of one of the new coatings with lower copper content was more similar to the commercial copper control while the rest were colonised by biofouling faster and/or at higher abundances. However, none of the tested products were able to prevent biofouling entirely, underlining the importance of the search for alternative and improved antifouling technologies

Effekter av organisk utslipp fra havbruk i Norge – en kunnskapsoppsummering

Uglem I, Järnegren J, Bloecher N. 2020. Effekter av organisk utslipp fra havbruk i Norge – en kunnskapsoppsummering. NINA Rapport 1884. Norsk institutt for naturforskning. Denne rapporten er en del av prosjektet «Kunnskaps- og erfaringskartegging om effekter av og muligheter for utnyttelse av utslipp av organisk materiale og næringssalter fra havbruk». Rapporten er en oppsummering av kunnskapen om miljøpåvirkninger fra utslipp av organisk materiale og næringssalter fra lakseanlegg. Organiske utslipp fra lakseoppdrett påvirker mange arter og ulike naturtyper på en rekke måter i likhet med andre naturbaserte næringer. For mange av artene eller naturtypene som påvirkes vil den totale effekten være begrenset og det er på bakgrunn av det som finnes av kunnskap liten grunn til å tro at effektene vil være så store at mange arter påvirkes på bestandsnivå eller at truede eller sårbare naturtyper påvirkes i så stort omfang at det er en risiko for at naturtypen går tapt i Norge. Ut fra det vi vet om ulike påvirkninger vil effekten av organiske utslipp i første rekke være lokal, men det er samtidig viktig å poengtere at mangel på kunnskap generelt ikke betyr at det ikke er negative påvirkninger. Organiske utslipp påvirker miljøet rundt oppdrettsanlegg på flere måter. Utslipp av begroingsorganismer fra oppdrettsanlegg kan teoretisk sett påvirke fisk som oppholder seg i nærheten av anleggene når notspyling foregår, og på lengre sikt bunnforholdene under anleggene ved at organismene sedimenterer. Det er imidlertid vanskelig å kvantifisere effekten av denne påvirkningen og mangelfull kunnskap gjør det ikke mulig å gjennomføre en grundig evaluering av potensielle effekter. Utslipp av løst organisk og uorganisk materiale fra havbruk er antatt å være den største menneskeskapte utslippskilden for løste næringssalter i Norge, men utslippet er beskjedent i forhold til den naturlige tilførselen. Utslipp av løst organisk materiale representerer en mindre andel av utslippene, har en lang omsetningstid i næringsnettet og anses ikke som særlig viktige for miljøforholdene rundt oppdrettsanlegget. Utslippet av løst uorganisk materiale er mye større, men vil med dagens produksjonsvolum ikke medføre økt risiko for redusert miljøtilstand på regional skala, selv om lokale effekter trolig kan forekomme. Kunnskapen om sammenhengen mellom utslipp av næringssalter og påvirkning på arter og økosystem er mangelfull og det er usikkert om og i hvilken grad negativ påvirkning forekommer per i dag eller vil oppstå ved økt framtidig produksjon. Partikulære organiske utslipp kan påvirke en lang rekke arter, både pelagiske og bentiske, samt ulike naturtyper. Påvirkningen skjer i hovedsak ved at de ulike artene inntar spillfôr, eller at spillfôr og fekalier sedimenteres på bunnen under oppdrettsanleggene. Påvirkning på bunnlevende organismer er vurdert i Havforskningsinstituttet sin risikorapport for Norsk havbruk for 2019 (Grefsrud mfl). Konklusjonen er det er lav risiko for ytterligere uakseptable miljøpåvirkninger på bunn-forhold som følge av partikulært organisk utslipp i alle produksjonsområder. Risiko for uakseptable miljøpåvirkninger på hardbunn vurderes som moderat, mens risikoen for bløtbunn er satt til lav. Selv om risikoen totalt sett vurderes som lav, kan imidlertid påvirkningen for enkelte individuelle lokaliteter være vesentlig. Det er vist at fisk og andre organismer som inntar spillfôr kan påvirkes negativt fordi spillfôr ikke er en naturlig diett for slike organismer eller fordi spillfôret inneholder medisiner som er skadelige for enkelte organismer. Det er ennå ikke dokumentert at slik påvirkning vil ha vesentlige negative miljøeffekter på bestandsnivå eller over større geografiske områder. Det er imidlertid utfordrende å undersøke denne typen problemstillinger siden undersøkelsene er ressurskrevende og man er avhengig av lange tidsserier for å kunne skille eventuelle effekter av organiske utslipp fra andre påvirkningsfaktorer. Dette betyr at selv om effekter på bestandsnivå ikke er dokumentert så vil ikke dette bety at det ikke er effekter. Spillfôr kan påvirke lokale fiskerier ved at fisk oppholder seg ved lakseanlegg og ikke på tradisjonelle fiskeplasser, samt at fisk som har spist spillfôr kan være av dårligere kvalitet enn fisk som har hatt en naturlig diett. Mulig kvalitetsforringelse hos villfisk på grunn av spillfôr i dietten er undersøkt i flere studier. Det er ikke funnet vesentlige gjennomsnittlige forskjeller i smak eller kvalitet mellom fisk som har spist spillfôr og fisk som har hatt en naturlig diett, men enkelte undersøkelser tyder på at en andel av seien som har spist spillfôr har redusert kvalitet. Miljøeffekter fra utslipp av organisk materiale fra landbasert settefiskanlegg er lite undersøkt, og denne kunnskapsoppsummeringen fokuserer derfor primært på effekter fra sjøbasert oppdrett. Selv om utslipp av organisk materiale fra oppdrettsanlegg fører til miljøpåvirkninger tas dette kun delvis hensyn til i dagens forvaltningssystem og i nasjonale bærekraftsvurderinger. Det er derfor behov for et mer helhetlig system for vurdering av miljømessig bærekraft i havbruksnæringen, som også tar hensyn til organiske utslipp, og som vil gi et mer fullstendig bilde av effektene slike påvirkninger kan ha på kystøkosystemene.Uglem I, Järnegren J, Bloecher N. 2020. Effects of organic waste from aquaculture in Norway – a knowledge summary. NINA Report 1884. Norwegian institute for nature research. This report is a part of the project “Mapping of knowledge and experiences on effects of, and opportunities for, utilisation of discharge of organic material and nutrients from aquaculture”. The report provides a knowledge summary regarding environmental effects caused by discharge of organic material and nutrients from salmon aquaculture. Organic discharge from salmon aquaculture affects many species and habitats in a variety of ways, as do all industries based on natural resources. The total effect will be minor for many species and based on existing knowledge, there is little reason to believe that the effects will be large enough to affect most species on population level, or that threatened or vulnerable ecosystems will be lost in Norway. From what we know of different stressors, the effect of organic discharge will mainly be local, but it is also important to point out that a lack of knowledge in general does not mean that there are no negative effects. Organic discharge affects the environment around a fish farm in many ways. Discharge of biofouling from fish farm equipment can theoretically affect resident fish when the cages are cleaned, and in the long run also the benthic environment underneath the farms by sedimentation of the biomass. It is difficult to quantify these effects and the lack of knowledge makes it challenging to thoroughly evaluate the potential effects. Discharge of dissolved organic compounds (DOC) and dissolved inorganic compounds (DIC) from aquaculture is presumed to be the largest human source of aquatic emission of dissolved nutrients in Norway, but the emission is modest in comparison to naturally occurring levels. Discharge of DOC represents a smaller part of the emission, it has a long life cycle and is not presumed to be of much importance for the environmental conditions around the farm. Discharge of DIC is much larger, but with the present production volume it will not increase the risk of reducing the environmental conditions on a regional scale, even if local effects likely may occur. The knowledge about how discharge of nutrients is connected to effects on species and ecosystems is lacking and it is uncertain if, and to what degree, a negative effect exists today or will occur in an increased production level in the future. Discharge of particulate organic matter (POM) may affect a range of species, both benthic and pelagic, as well as different nature types. The effect occurs mainly by consumption of waste feed or that waste feed and faeces settle on the bottom underneath the fish farm. The effects on benthic organisms are assessed in the risk-report for Norwegian aquaculture 2019 from the Institute of Marine Research (Grefsrud et al.). The conclusion is that there is a low risk for further unacceptable effects on the bottom conditions due to POM discharge in all production areas. The risk for unacceptable environmental effects on hard bottoms is assessed as moderate, while the risk for soft bottoms are considered as low. Even if the total risk is considered low, the effect on some individual locations may be substantial. It has been shown that fish and other organisms that utilises waste feed may be negatively effected as this is not their natural diet or because the waste feed contains medicines that are harmful for some organisms. It has so far not been documented that such effects will have substantial negative environmental effects on population level or over larger geographical areas. However, it is challenging to investigate this type of issues as it would require large efforts and long time series of data to be able to separate effects of organic discharge from other factors. This means that even if effects at population level is not documented, it does not mean that there are no effects. Waste feed can affect local fisheries by attracting wild fish to fish farms rather than staying at the traditional fishing grounds. Fish eating waste feed may also have reduced meat quality compared to fish on a natural diet. The potential for reduced quality in wild fish due to a waste-feed diet has been investigated in several studies. No substantial average differences have been detected in taste or quality between fish that has been eating waste feed and fish on a natural diet, but a few studies imply reduced quality in some of the saithe feeding on waste feed. The environmental effects of organic matter from land based fish farms has been very sparingly investigated and this knowledge summary has therefore focused on the effects of ocean based farming. Even if discharge of organic matter from fish farms leads to environmental effects, this is only partly taken into consideration in the present national management system and sustainability assessments. Therefore, there is a need for a more comprehensive system to evaluate environmental sustainability in aquaculture that also considers organic discharge and that will give a more complete picture of the effects such stressors might have on the coastal ecosystems

Efficacy testing of novel antifouling systems for marine sensors

Marine sensors are widely employed tools for remotely providing a representation of their environment. The primary factor limiting measurement accuracy and deployment longevity is biofouling. For prevention, copper is the most widely applied biocide, often in form of adhesive copper tapes. However, for complex shapes these tapes are challenging to apply. Furthermore, sensor operating life frequently exceeds the antifouling protective period of the tape and the exchange of antifouling systems can be prohibitively time consuming and expensive. Alternative antifouling systems are needed to improve the cost-effectiveness of marine monitoring. This study tested a novel adhesive antifouling film based on copper cold spray technology in two concentrations (586 g m−2 and 306 g m−2) against a commercial copper tape (367 g m−2) and an uncoated control. After ten months of immersion, the lower concentration adhesive film performed equal to the commercial copper tape while achieving higher durability and better leaching control. In contrast, the antifouling performance of the high-concentration film was at times lower than that of the commercial copper tape, likely due to high embedment depth of copper particles. Customizable, cold spray metallised adhesive films may offer an advantage compared to ‘traditional’ tapes, including the potential to reduce copper emissions

Biofouling in marine aquaculture: a review of recent research and developments

Biofouling in marine aquaculture is one of the main barriers to efficient and sustainable production. Owing to the growth of aquaculture globally, it is pertinent to update previous reviews to inform management and guide future research. Here, the authors highlight recent research and developments on the impacts, prevention and control of biofouling in shellfish, finfish and seaweed aquaculture, and the significant gaps that still exist in aquaculturalists’ capacity to manage it. Antifouling methods are being explored and developed; these are centred on harnessing naturally occurring antifouling properties, culturing fouling-resistant genotypes, and improving farming strategies by adopting more sensitive and informative monitoring and modelling capabilities together with novel cleaning equipment. While no simple, quick-fix solutions to biofouling management in existing aquaculture industry situations have been developed, the expectation is that effective methods are likely to evolve as aquaculture develops into emerging culture scenarios, which will undoubtedly influence the path for future solutions