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Lágmörkun á streitu laxfiska við meðhöndlun í eldi getur skipt sköpum í að tryggja velferð, vöxt og viðgang fiskanna, sem og gæði og geymsluþol loka afurða. Streita við meðhöndlun, t.d. gegn lús, getur dregið úr viðnámsþrótti fiska gegn sýkingum og kulda ásamt því að draga úr vexti; því það getur tekið laxinn nokkurn tíma að jafna sig og byrja að taka fóður aftur. Ef dæling á fiski til slátrunar veldur mikilli streitu sem getur haft áhrif á gæði afurða. Einnig er mikilvægt að mæta kröfum um dýravelferð við fiskeldi samhliða auknum þrýstingi frá neytendum. Vitað er að vakúmdælur, sem eru mest notaðar í fiskeldi í dag, valda töluverðri streitu, afföllum og lakari gæðum, enda gengur mikið á við dælingu þar sem loftrými með fiski er lofttæmt og síðan skotið áfram til að dæla fiskinum. Því hafa framleiðendur dælubúnaða verið að leita nýrra leiða við dælingu laxfiska og hefur íslenska fyrirtækið Skaginn 3X verið að þróa svokallaða spíraldælu (Archimedesar dælu) sem lausn á þessu vandamáli. Dælan hefur hlotið nafnið ValuePump. Í þessu verkefni var smíðuð frumgerð af dælunni og svo voru gerðar samanburðartilaunir á henni og hefðbundinni vakúmdælu, þar sem streita í fiski við dælingu var mæld með hjartsláttarnemum, ásamt mælingum á myndun streituhormóna í blóði. Í þessu verkefni var smíðuð frumgerð af dælunni og svo voru gerðar samanburðartilaunir á henni og hefðbundinni vakúmdælu, þar sem streita í fiski við dælingu var mæld með hjartsláttarnemum, ásamt mælingum á myndun streituhormóna í blóði. Niðurstöðurnar sýndu marktækan mun á milli hópa í kjölfar dælingar. Hjartsláttur hækkaði mikið við dælingu en ValuePump hópurinn var fljótari að jafna sig og ná aftur grunngildi. Dæling með vakúmdælu hafði mun meiri langvarandi streituáhrif en tilraun með hámarksáreiti þar sem fiskurinn spriklaði á þurru. Mikill sjónrænn munur var einnig á hópunum eftir dælutegundum, þar sem fiskar sem dælt var með vakúmdælu komu oft slasaðir eða jafnvel dauðir úr dælunni, syntu á hlið eða á hvolfi klukkutímum eftir dælingu. Fiskur sem dælt var með ValuePump varð hins vegar ekki fyrir neinu sjáanlegu hnjaski við dælinguna og virtist vel á sig komin að henni lokinni. Niðurstöður samanburðartilraunanna verða að teljast mjög jákvæðar, en þó er þörf á frekari rannsóknum til að skera endanlega úr um kosti ValuePump umfram hefðbundnar vakúmdælur. Ljóst virðist á niðurstöðum verkefnisins að lax sem dælt er með ValuePump sé fljótari að ná sér eftir dæling og þá byrja aftur að taka fóður. Niðurstöður hvað varðar dælingu til slátrunar eru ekki eins augljósar og þarfnast frekari rannsókna, þá sér í lagi þar sem rannsaka þarf fisk sem kominn er í sláturstærð við raunaðstæður. _____ Minimizing the stress of salmonids during handling and before slaughtering can be extremely important for welfare, survival and growth, as well as to ensure overall quality and shelf-life of the final products. Stress during treatment, e.g., against lice, can reduce the resistance of fish to infections and cold seawater as well as reduce growth which may take the salmon some time to recover from stress and start feeding again. If the pumping of fish for slaughter causes a lot of stress, it can affect the quality of the products. Animal welfare is also becoming more important in aquaculture with increased welfare demands from the consumers. It is known that vacuum pumps, that are most commonly used in the aquaculture industry today, cause considerable stress, loss and poor quality, as pumping causes a lot of discomfort for the fish. Companies have therefore been searching for an alternative to vacuum pumping for some time. The Icelandic company Skaginn 3X has for some time been developing a so-called Archimedes pump to replace vacuum pumps. In this project, a prototype of the Archimedes pump (called ValuePump) was made, and then compared to a conventional vacuum pump. The pumping stress of fish was measured by cardiac sensors along with the measurement of a stress hormone Over a 4-week period, 100 salmons (1 kg average weight) were pumped once weekly with either pump, including 20 salmons implanted with heart rate loggers from Star-Oddi. Experiments were carried out in the facilities of the Marine and Freshwater Research Institute in Reykjanes under supervision of specialists in aquaculture and the use of cardiac sensors. The results showed a significant difference in heart rate recovery between the two groups. There was a large increase in heart rate immediately after pumping but the ValuePump group recovered more quickly to pre-pumping levels. Pumping with the vacuum pump caused a larger and longer stress effect then an applied max stress chase protocol. There was also a considerable visible difference between the two groups, where the vacuum pump fish were injured or even dead after pumping, swimming on the side or upside down for hours after pumping. The ValuePump fish, however, received no visible physical damage from the pumping and seemed fit. The results of the comparative studies indicate very positive results, but further studies are however needed to validate the results. It is apparent that salmon pumped with ValuePump is faster to recover than when pumped with vacume pumps and is as results faster to start feeding again after handling. Results regarding pumping of fish for slaughtering are not as comprehensive and need to be studied further, particularly by analysing fish that has reached slaughter size and preferably in real industry setting., Styrktaraðilar/Funding: Matvælasjóður (ANR 20090620/1210)

The effects of early thermal environment on growth, age at maturity, and sexual size dimorphism in Arctic charr (Salvelinus alpinus) are investigated. This study is a 654-day long rearing trial split into two sequential experimental phases termed EP1 and EP2 and lasting 315 and 339 days, respectively. EP1 started at the end of the yolk sac stage when the experimental fish were divided into three groups and reared at different target temperatures (7, 10 and 12 °C). During EP2, all groups were reared at the same temperature (7–8 °C) until harvest (~1300 g). Growth rates increased with temperature from 7 to 12 °C, and at the end of EP1 the 12C group had 49.0% and 19.2% higher mean weight than groups 7C and 10C, respectively. Elevated early rearing temperatures were, however, found to cause precocious sexual maturation and reduce the long-term growth performance. At the end of EP2, the 7C group had 3.6% and 14.1% higher mean weight than 10C and 12C, respectively. Elevated early rearing temperatures had a much stronger effect on the maturity incidence of females, and while male-biased sexual size dimorphism (SSD) was found in all groups, the magnitude of SSD was positively associated with temperature.

Stable supplies of high quality cod larvae and juveniles are urgently needed for the development of successful cod farming industries in countries around the North Atlantic. The project is a collaboration between key actors from the cod farming industry and the research sector in Iceland, Norway and the Faroe Islands, with involvement of additional key actors and stakeholders within the Nordic countries and Canada