The use of Algorithm-Assisted Feeding for Innovation and Increased Productivity in Aquaculture

Abstract: The need for innovation in aquaculture has escalated in tandem with the use of advanced production equipment and high-level biological competence. A Norwegian company, NorseAqua A/S, produces sonar equipment that provides both images and data on how the salmon are distributed in the cage. The sonar data provides a basis for calculating algorithms between the depth of salmon in the cage and other key factors used to make decisions about how the salmon should be fed. The first aspect of the project was to investigate how the equipment was working and verify that the sonar data was readable. The second aspect was to analyze the relationships between important variables of significance for the feeding process of the salmon (including the sonar measurements). A third aspect was determining what understanding the feeding operators gained from the information produced. The results show that it is possible to develop algorithms based on the sonar data that improve feeding efficiency.publishedVersio

Submerged cage aquaculture of marine fish: a review of the biological challenges and opportunities

Surface-based cages are the dominant production technology for the marine finfish aquaculture industry. However, issues such as extreme weather events, poor environmental conditions, interactions with parasites, and conflicts with other coastal users are problematic for surface-based aquaculture. Submerged cages may reduce many of these problems and commercial interest in their use has increased. However, a broad synthesis of research into the effects of submerged culture on fish is lacking. Here, we review the current status of submerged fish farming worldwide, outline the biological challenges that fish with fundamentally different buoyancy control physiologies face in submerged culture, and discuss production benefits and problems that might arise from submerged fish farming. Our findings suggest that fish with closed swim bladders, and fish without swim bladders, may be well-suited to submerged culture. However, for fish with open swim bladders, such as salmonids, submergence is more complex as they require access to surface air to refill their swim bladders and maintain buoyancy. Growth and welfare of open swim bladder fish can be compromised by submergence for long periods due to complications with buoyancy regulation, but the recent addition of underwater air domes to submerged cages can alleviate this issue. Despite this advance, a greater understanding of how to couple advantageous environmental conditions with submerged culture to improve fish growth and welfare over the commercial production cycle is required if submerged cages are to become a viable alternative to surface-based cage aquaculture.publishedVersio

Hummer - biologi, fiske og forvaltning

The European lobster (Hornarus gammarus) can become very old and a maximum age of 50 years have been suggested. Compared to crabs and spiny lobsters, the fecundity of lobsters is relatively low per hatching. The eggs hatch into quite large but vulnerable planctonic larvae, which develop through four moults into bottom-living juveniles. The first two or three egg batches seem to be of both lower quantity and quality than later batches. During the larval stages predation probably is high and the larvae are sensitive to unfavourable climatic conditions. Norway is located at the northern border of the geographical distribution area of lobsters and low summer temperature can induce delayed hatching and larval development, resulting in years with considerably reduced recmitment. Thus, it can be anticipated that the lobster stock in Norway is vulnerable for overexploitation, since the recmitment is not stabile. Lobsters have been traded in Europe for more than 300 years, and about 100 years in America. The American lobster is numerous and the fishery is economically viable in coastal comrnunities both in north-eastem USA and along the east coat of Canada. The European lobster landings are only 2.5 % of the American lobster landings. Outside Great Britain, no lobster populations in Europe can support a year round fishery. Some still remember "the good old days" in Norway, when each trap contained at least one lobster even when they were hauled twice a day. Today, one lobster per 10 traps each day is regarded as good. The reduced lobster stock could be a result of long-term overexploitation. The size composition of landed lobster through the history, indicates that intensity and effectivity of the fishery had and has a major impact on the populations. The population is now at a minimum and a restoration through natural reproduction will probably take very long time, irrespective of management strategy. Since the early 1960s and until today there is caught less lobster in Norway per year than ever before, both measured as registered landings and catch per unit effort. The marked value of the yearly landings (app. 30 metric tons (t)) is about 1 000 000 &. If the yearly landings could be increased to 500 t, the marked value would be approximately 15 000 000 £. Obviously, this would lead to a rewarding fishery. The present Norwegian management do not protect the population from overexploitation. The lobster fishery is generally restricted by seasonal protection from 1 June to 1 October, and als0 from 1 January to 1 October on the south-east coast. In addition the minimum legal size generally is set at 25 cm total length, except on the south-east coast where the minimum legal size is 24 cm total length. The only legal fishing gear is lobster pots. The lobster stock might be increased either through releasing cultured juveniles or through an improved management strategy. In Norway several efforts have been made to enhance the lobster stocks through releasing reared larvaeljuveniles, but no increase in abundance has been documented, mainly due to the absence of a reliable tagging procedure. In addition the released lobsters were young and fragile (pelagic lwae and pstlarvae) and the surrvival can thus be expected to be low. The Institute of Marine Research has since 1988 released 6-12 months old, micro-wire-tagged juveniles. It is still too early to evaluate the effect of these releases, but five years after the first large scale release, the landings at the release locations constitute of 30-60% released lobsters. It is, however, unclear if it is possible to produce a sufficient number of juveniles to enhance the total Norwegian lobster stock. The management strategy might be improved considerably, with the main aim towards a legislation that assures a sustainable reasonable exploitation without reducing the recmitment. Primarily, the spring fishery should be closed and a maximum legd size should be introduced. This would lead to an increased protection of large highly reproductive animais. Secondly, restnctions in use and adjustments in design of other bottom fishing gear should be evaluated. In situations with seriously depleted locd stocks a total stop in the fishery als0 should be appraised. Improved public information and biologicd monitoring of the stock would be important elements in any new effort of enhancing the Norwegian lobster population. NORSK SAMMENDRAG:Hummeren kan bli svært gammel, kanskje så mye som 50 år. Den produserer forholdsvis få avkom pr. år, men kan til gjengjeld forplante seg hele livet. Det er uklart om de første kullene har høy overlevelsesevne, siden hunnene ikke er i stand til å produsere egg av topp kvalitet før etter flere gytinger. I tillegg er larvene sårbare for klimaforhold og rovdyr, slik at naturlig overlevelse det første året er lav. Norge ligger helt nord i hummerens utbredelsesområde, og lave sommertemperaturer sannsynliggjør at rekrutteringen kan være særlig lav i år med ugunstige klimaforhold. Derfor kan en for hummer forvente at det på samme måte som for marine fiskearter finnes gode og dårlige år, noe som igjen kan medføre at hummeren langs norskekysten er spesielt sårbar for overfiske siden reproduksjonen ikke er stabil. Eldre fiskere minnes rekordfangster på en hummer pr. teine og teinetrekk to ganger i døgnet. Siden 1960-årene har imidlertid 6n hummer i døgnet pr. 10 teiner vært ansett som et godt utbytte. Til tross for lave fangster, blir mange av de lokale bestandene utsatt for hard beskatning hvert år og en kan anta at fiske er den viktigste bestandsregulerende faktoren. Hummerfisket har endret seg betraktelig i etterkrigstiden. Fra å være et kommersielt deltidsfiske, har økningen i antall motoriserte småbåter og bruken av kysten i fritidsøyemed ført til at andelen ulovlig fiske har tiltatt. Selv om det ulovlige fisket er medvirkende til at hummerbestanden er liten, så bør det heller ikke underslås at det lovlige fisket, slik det er i dag, også er for stort. Det er for eksempel vist at vårfisket tar ut en høy andel av de store og mest reproduktive hunnene. Med dagens forvaltning og fiskepress, vil hummerbestanden bli fisket ned før den har fått utnyttet sitt forplantningspotensial. Historien har lært oss at bestandsøkninger vil bli fulgt av økt fiske, med påfølgende ytterligere bestandsnedganger. Slik hummerfisket foregår i dag, kan en ikke forvente at bestanden kan økes varig. Hummerbestanden er forsøkt styrket på to måter. Enten gjennom utsetting av oppdrettede yngel eller gjennom en bedret forvaltning. Forsøk på styrking av bestander gjennom utsetting av yngel har foregått i over hundre år, men resultatene er umulig å vurdere, hovedsakelig fordi den utsatte yngelen ikke var merket. Havforskningsinstituttet startet imidlertid utsetting av merket yngel i 1988 og foreløpige gjenfangster viser at utsatt hummer utgjør en stor andel av fangstene i utsettings- området. Det er imidlertid for tidlig å vurdere om det er mulig å produsere et tilstrekkelig antall yngel til å kunne styrke bestanden på landsbasis. Forvaltningen kan bedres på flere punkter, og hovedmålsettingen bør være å arbeide mot et regelverk som sikrer en langsiktig beskatning uten å svekke rekrutteringen. Tiltak som i første rekke bør vurderes er vårfredning i hele landet og innføring av et maksimumsmål. Disse tiltakene vil beskytte store reproduktive hunner i større grad enn ved dagens regler. I andre rekke kan redskapsrestriksjoner som hindrer hummer som bifangst i fiske etter andre arter være aktuelle tiltak. En forutsetning for redskapsrestriksjoner er at fisket etter andre arter ikke blir påvirket i vesentlig grad. Som et krisetiltak kan også totalfredning være aktuelt. Utsetting av yngel kan komme i tillegg til andre tiltak for å sikre regelmessig lokal rekruttering i områder med høyt fiskepress. Holdningsendrende informasjon og faglig overvåkning av bestanden må være viktige element for å vurdere effekten av faktorer i framtidig hummerforvaltning

Behavioural indicators of welfare in farmed fish

Behaviour represents a reaction to the environment as fish perceive it and is therefore a key element of fish welfare. This review summarises the main findings on how behavioural changes have been used to assess welfare in farmed fish, using both functional and feeling-based approaches. Changes in foraging behaviour, ventilatory activity, aggression, individual and group swimming behaviour, stereotypic and abnormal behaviour have been linked with acute and chronic stressors in aquaculture and can therefore be regarded as likely indicators of poor welfare. On the contrary, measurements of exploratory behaviour, feed anticipatory activity and reward-related operant behaviour are beginning to be considered as indicators of positive emotions and welfare in fish. Despite the lack of scientific agreement about the existence of sentience in fish, the possibility that they are capable of both positive and negative emotions may contribute to the development of new strategies (e. g. environmental enrichment) to promote good welfare. Numerous studies that use behavioural indicators of welfare show that behavioural changes can be interpreted as either good or poor welfare depending on the fish species. It is therefore essential to understand the species-specific biology before drawing any conclusions in relation to welfare. In addition, different individuals within the same species may exhibit divergent coping strategies towards stressors, and what is tolerated by some individuals may be detrimental to others. Therefore, the assessment of welfare in a few individuals may not represent the average welfare of a group and vice versa. This underlines the need to develop on-farm, operational behavioural welfare indicators that can be easily used to assess not only the individual welfare but also the welfare of the whole group (e. g. spatial distribution). With the ongoing development of video technology and image processing, the on-farm surveillance of behaviour may in the near future represent a low-cost, noninvasive tool to assess the welfare of farmed fish.Fundação para a Ciência e Tecnologia, Portugal [SFRH/BPD/42015/2007]info:eu-repo/semantics/publishedVersio

Biological criteria for submergence of physostome (Atlantic salmon) and physoclist (Atlantic cod) fish in sea-cages

This thesis aims to describe behavioural responses and welfare parameters for the physostome Atlantic salmon and physoclist Atlantic cod when out of neutral buoyancy at different degrees and periods of time. The background for this approach is to improve the culture conditions by fully submergence of the farming installations, as the water below 10 m depth often is more stable in terms of environmental factors such as temperature and current in addition to the lack of waves, which again opens for alternative sites in more exposed oceanic areas. Salmon were submerged in large-scale fully submersible cages at depths between 4 to 15 m for 22 days (Paper I) and 10 to 25 m for 42 days (Paper II) under different light conditions and at various times of year. The behaviour of individual salmon in a school under submerged conditions was studied to reveal whether a range of coping abilities among individuals exists during the new and more challenging conditions (Paper III). Atlantic cod in an experimental submersible cage were raised from five different starting depths (between 30 and 8 m) and lowered from surface position to 10 m, 20 m and 30 m to test a protocol for safe lifting and lowering steps. Based on the behavioural responses, safe acclimation times before the next vertical step at high and low sea temperatures were identified (Paper IV). In Papers I and II, the general patterns of swimming depth and schooling density were studied at group level using echo-sounders in addition to swimming speed and swimming angle based on instantaneous observations with underwater cameras. Welfare parameters were defined as weight gain, feed intake, feed utilisation and fin and vertebral condition during the experimental period. The behaviour of individual salmon was studied by monitoring the swimming depth and body temperature using data storage tags implanted in randomly selected fish. Whether the development of diel vertical migration (DVM) activity during feeding was linked with individual growth rates was analysed to study individual coping styles. The immediate response and recovery time after lifting and lowering of Atlantic cod were estimated through measurements of swimming speed, swimming tail beat rate and swimming angle based on underwater camera recordings, and additionally by echo-sounder data obtained from resting fish on the net-floor (Paper IV). Atlantic salmon submerged without the opportunity to refill their swim bladder lost gas steadily over time, and the bladder was empty after about three weeks (Papers I and II). Swimming speeds were elevated on the first day after submergence and schooling became more structured (more constant speed and a greater distance to neighbouring fish). The diurnal vertical swimming pattern for the salmon in spring was broadly similar to that observed prior to submergence, as the artificial underwater lighting allowed the salmon to keep high swimming speed and lift during night (Paper III). In contrast, about 90% of the salmon submerged below 10 m during the dark winter reversed their diurnal pattern from swimming at shallow depths at night and deeper during the day to swimming deep at night and shallower during the day (reversed DVM) or to swimming with a normal or reversed diurnal pattern on different days (irregular). A separation of faster- and slower-growing salmon also gradually appeared, where the faster-growing individuals occupied the deeper part of the water column. This situation occurred also at night at the end of the experiment among the salmon given continuous light (Paper III). Growth was clearly reduced in the salmon that were submerged during the winter, with more injuries recorded on their fins and snout. Slightly compressed vertebrae in the tail region were also observed, probably due to their tilted head-up tail-down swimming angle during the dark nights (Paper II). Lifting farmed cod from five different start depths, equivalent to a 40% pressure reduction, resulted in strong downwards swimming movements dependent on the water temperature (Paper IV). The depth before cage lifting affected the immediate response, as the fish became more active after lifting events from shallow compared to deeper depths. Appetite decreased after lifting, but loss of behavioural control was never observed. During the subsequent 8-10 hr recovery periods, swimming activity gradually decreased to the same level as before lifting. The overall recovery time did not depend on start depth or temperature. Independent of final depth or temperature, rapid lowering of cod only resulted in a moderate short-term increase in upwards swimming movements, while appetite was less affected than after lifting. A compressed swim bladder after descents from the surface to 10-30 m leads to negative buoyancy, which required 18-90 h to re-fill by gas secretion, which is a temperature-related process (Paper IV). In conclusion, this thesis demonstrates that air gulping is a behavioural need for Atlantic salmon, and that long term denial of surface access will reduce their welfare Atlantic cod cope well in fully submerged cages, but 40% pressure reduction is near the upper limit for lifts of healthy farmed cod. Secondary lifts should not be done until at least 10 h after the first lift. Cage lowering should be done slowly to avoid potentially stressful crowding of negatively buoyant fish on the cage bottom, especially at low temperatures

Idømmelse av samfunnsstraff ved kroppsskade. En analyse av de hensyn som vektlegges i straffutmålingen - aktualisert ved HR-2019-1780-A.

Det ledende utgangspunktet for kroppsskade er at det skal idømmes ubetinget fengsel. I rettspraksis har man i stor grad fulgt dette utgangspunktet, men gjort unntak primært hvor det kunne konstateres en rehabiliteringssituasjon. Dette gir et snevert anvendelsesområdet for samfunnsstraffen, men etter HR-2019-1780-A, hvor det ble idømt samfunnsstraff på bakgrunn av tiltaltes skjøre livssituasjon, kan det stilles spørsmål om ikke anvendelsesområdet nå er utvidet. Oppgaven analyserer betydningen dommen kan få for fremtidig bruk av samfunnsstraff, samt hvilken betydning dommen har fått i underrettspraksis

Imposition of community sentence for bodily harm. An analysis of the considerations emphasized in the sentencing - actualized by HR-2019-1780-A

Det ledende utgangspunktet for kroppsskade er at det skal idømmes ubetinget fengsel. I rettspraksis har man i stor grad fulgt dette utgangspunktet, men gjort unntak primært hvor det kunne konstateres en rehabiliteringssituasjon. Dette gir et snevert anvendelsesområdet for samfunnsstraffen, men etter HR-2019-1780-A, hvor det ble idømt samfunnsstraff på bakgrunn av tiltaltes skjøre livssituasjon, kan det stilles spørsmål om ikke anvendelsesområdet nå er utvidet. Oppgaven analyserer betydningen dommen kan få for fremtidig bruk av samfunnsstraff, samt hvilken betydning dommen har fått i underrettspraksis.MasteroppgaveJUS399MAJURMAJUR-

Torskeoppdrett i nedsenkede merder?

På grunn av torskens forkjærlighet for lavere sommertemperaturer og høyere vintertemperaturer enn det man ofte finner i de øverste lagene i vannsøylen, har både kommersielle aktører og forskere forsøkt med oppdrett av torsk i dype eller nedsenkede nøter. En av utfordringene med dette konseptet er at torskefisk har lukket svømmeblære som skaper problemer ved store og raske trykkendringer. Basert på undersøkelser av torskens egen toleransegrense for trykkreduksjon, har vi forsøkt å etablere prosedyrer for sikker heving og senking av oppdrettstorsk i lukkete, nedsenkbare merder

The use of Algorithm-Assisted Feeding for Innovation and Increased Productivity in Aquaculture

Abstract: The need for innovation in aquaculture has escalated in tandem with the use of advanced production equipment and high-level biological competence. A Norwegian company, NorseAqua A/S, produces sonar equipment that provides both images and data on how the salmon are distributed in the cage. The sonar data provides a basis for calculating algorithms between the depth of salmon in the cage and other key factors used to make decisions about how the salmon should be fed. The first aspect of the project was to investigate how the equipment was working and verify that the sonar data was readable. The second aspect was to analyze the relationships between important variables of significance for the feeding process of the salmon (including the sonar measurements). A third aspect was determining what understanding the feeding operators gained from the information produced. The results show that it is possible to develop algorithms based on the sonar data that improve feeding efficiency

Prisdiskriminering i den amerikanske nybilbransjen : en studie av den amerikanske nybilbransjen, om det eksisterer prisdiskriminering og mulige årsaker til dette

Forhandlinger er en stor del av prosessen rundt det å kjøpe seg ny bil. Det har imidlertid vært diskutert i flere tidligere studier hva som påvirker rabatten man oppnår. Spørsmålene som er stilt er blant annet om det er hvor dyktig kjøperen er til å forhandle eller om det er noe annet som ligger bak. Ulike årsaker som har blitt trukket frem er for eksempel hvilket folkeslag man tilhører eller hvilket kjønn man har. Hovedformålet med denne utredningen er å undersøke om det eksisterer tredjegrads prisdiskriminering på det amerikanske nybilmarkedet, hvilke faktorer som eventuelt kan forklare prisdiskrimineringen, og om konsumentens folkeslag og kjønn er noen av dem. For å gjøre dette har vi tatt utgangspunkt i en amerikansk forbrukerundersøkelse, Consumer Expenditure Survey. Denne blir gjennomført kvartalsvis og respondentene svarer på detaljerte spørsmål knyttet til forbruksdata som blant annet inntekt og bosted, men også informasjon knyttet til bilkjøp som pris og hvilken type bil de har kjøpt. Studien er ment som en oppfølgingsstudie av studien ”Dealer Price Discrimination in New Car Purchases: Evidence from the Consumer Expenditure Survey” som er utført av Pinelopi Koujianou Goldberg i 1996. Hun har i sin studie tatt for seg årene 1983 til 1987, mens vi ønsker å se nærmere på årene 2000 til 2004. I vår studie finner vi at det eksisterer prisdiskriminering på det amerikanske nybilmarkedet, men vi finner ingen konkluderende beviser for at folkeslag og kjønn påvirker rabatten man oppnår i forhandlingene. På den annen side finner vi store variasjoner i prisene konsumentene betaler ved kjøp av de samme bilmodellene. Dette indikerer at det er lønnsomt for bilforhandlerne å bedrive prisdiskriminering ettersom konsumentene har ulike reservasjonspriser og tålmodighet i en forhandlingssituasjon.nhhma