New aquaculture production systems are evolving for prolong of Atlantic salmon smolts or post-smolts before stocking in traditional net pens, such as semi-closed containment (S-CCS) sea (Fig. 1) and recirculating (RAS) on land. The microbiota these can potentially have great impact the robustness health fish. These two types likely to different challenges regarding pathogenic invasion due water management, e.g. treatment intake turnover water. In this study, we investigated bacterial both...

With increasing freshwater scarcity and greater use of seawater, fluctuating salinities are becoming common in water treatment systems. This can be challenging for salinity-sensitive processes like nitrification, especially recirculating aquaculture systems (RAS), where maintaining nitrification efficiency is crucial fish health. study was undertaken to determine if prior exposure seawater (priming) could improve moving bed biofilm reactors (MBBR) under salinity increase from seawater. The...

Abstract Periods of fasting occur for a multitude reasons in Atlantic salmon aquaculture. Feed withdrawal is widely used prior to transport, parasite treatments, preslaughter and depuration purposes recirculating aquaculture systems. Voluntary coping response when fish have poor health or are exposed farm environments. Owing increased attention animal welfare aquaculture, concerns been raised regarding ethical issues farmed subjected fasting. However, thorough science‐based recommendations...

High carbon dioxide (CO2) concentrations negatively impact fish, which makes data on its tolerance especially relevant for production systems that can accumulate CO2 such as recirculating aquaculture system (RAS). The current study evaluates the effect of growth performance, welfare, and health Atlantic salmon post-smolts in RAS. This consisted two phases. first was a exposure phase, where eighteen tanks were used with six treatments triplicate: 5, 12, 19, 26, 33 40 mg/L during 12 weeks ppt...

When operating water recirculating systems (RAS) with high make-up flushing rates in locations that have low alkalinity the raw water, such as Norway, knowledge about required RAS concentration is important. Flushing containing washes out valuable base added to (as bicarbonate, hydroxide, or carbonate), which increases farm costs when concentrations are maintained; however, must not be so it interferes nitrification pH stability. For these reasons, a study was designed evaluate effects of on...

Abstract Producing a larger post‐smolt in recirculating aquaculture systems (RAS) could shorten the production time sea cages and potentially reduce mortality. Knowledge of biological requirements post‐smolts closed‐containment is however lacking. In present study, effects salinity water velocity on growth, survival, health, welfare Atlantic salmon reared RAS were examined. Salmon smolts stocked three separate with salinities 12, 22, 32‰ subjected to high (1.0 body lengths per s −1 ) or low...

The multiplicity or loss of the vitellogenin (vtg) gene family in vertebrates has been argued to have broad implications for mode reproduction (placental non-placental), cleavage pattern (meroblastic holoblastic) and character egg (pelagic benthic). Earlier proposals existence three forms vertebrate vtgs present conflicting models their origin subsequent duplication. By integrating phylogenetics novel vtg transcripts from old modern teleosts with syntenic analyses all available genomic...

Recirculating aquaculture systems (RAS) are increasingly being used for Atlantic salmon smolt production. However, knowledge of how the RAS environment affects welfare and performance is limited. For instance, safe limits chronic exposure to typical compounds in RAS, such as NH3-N, NO2-N, CO2 should be established salmon, well their interactions with nutrition, other water compounds, microbiota. These questions can best answered a research facility that providing environment. In addition,...

The objective of this study was to determine the long-term effects ambient unionized ammonia nitrogen (NH3-N) combined with different feeding regimes on Atlantic salmon Salmo salar L parr growth, welfare and smoltification. Previous studies stage have mostly focused acute exposure, or at low temperatures. were exposed for 105 days (at 12°C, pH 6.8) four sublethal concentrations ranging from 0.1 35 μg L−1 NH3-N (0.1–25 mg TAN) two levels: full feed strength (+20% overfeeding) 1/3 strength....

Abstract Production of Atlantic salmon smolts in recirculation aquaculture systems (RAS) is growing, and novel production protocols using continuous light RAS are being implemented the industry. In present study, Salmon parr were exposed to either a traditional protocol (short‐day winter signal [12:12 L:D] for 6 weeks) or light. Both photoperiods applied freshwater (FW) brackish water RAS. from all treatments transferred seawater pens at 200 600 g grown until slaughter size. A control group...

The objective of this study was to determine the underlying physiological and molecular responses long-term sublethal ammonia exposure in Atlantic salmon (Salmo salar) parr. Previous studies have predominately focused on mechanisms during acute, short-term exposure. For that purpose parr were exposed four concentrations between 4 1800 μmol l−1 total nitrogen (TAN), subjected two feeding regimes for 15 weeks. Elevated environmental full strength caused an initial increase plasma levels...

Ozone is a strong oxidant, and its use in aquaculture has been shown to improve water quality fish health. At present, it predominantly used freshwater systems due the high risk of toxic residual oxidant exposure brackish seawater. Here, we report effects ozone on Atlantic salmon (Salmo salar) post-smolts (~100 g), (12 ppt) flow-through system. Salmon were exposed oxidation reduction potential concentrations 250 mV (control), 280 (low), 350 (medium), 425 (high) 500 (very high). The...

Nitrifying biofilms developed in brackish water are reported to be more robust salinity changes than freshwater biofilms. This makes them a promising strategy for treatment systems with variable salinity, such as recirculating aquaculture Atlantic salmon. However, little is known about the time required nitrification start-up or microbial community dynamics. To investigate development of nitrifying at intermediate we compared startup moving bed biofilm reactors virgin carriers brackish- (12‰...

Fish encounter oxidative stress several times during their lifetime, and it has a pervasive influence on health welfare. One of the triggers in fish farming is use disinfectants to improve rearing conditions, especially production systems employing recirculation technology. Here we report physiological morphological adaptive responses Atlantic salmon (Salmo salar L.) post-smolts intermittent exposure potent agent peracetic acid (PAA). reared semi-commercial scale brackish water recirculating...

Previous research and experience has linked elevated dissolved carbon dioxide (CO2) to reduced growth performance, poor feed conversion, a variety of health issues in farm-raised fish, including Atlantic salmon Salmo salar. Supplemental control measures water recirculation aquaculture systems (RAS) reduce CO2 accumulation, however, such as increased pumping decrease tank hydraulic retention time, can represent significant costs for operators. We exposed post-smolt S0 (197 ± 2 g, 423 days...

Recirculating aquaculture systems (RAS) are a new alternative to traditional approaches, allowing full control over the fish production conditions, while reducing water demand. The reduction of exchange leads an accumulation dissolved organic matter (DOM) that can have potential effects on quality, welfare and system performance. Despite growing awareness DOM in aquaculture, scarce scientific information exists for understanding composition transformation RAS. In this study, non-targeted...

The skin barrier consists of mucus, primarily comprising highly glycosylated mucins, and the epithelium. Host mucin glycosylation governs interactions with pathogens stress is associated impaired epithelial function. We characterized Atlantic salmon function during chronic (high density) O-glycosylation changes in response to acute stress. Fish held at low (LD: 14–30 kg/m3) high densities (HD: 50-80 were subjected 24 h before sampling 17 21 weeks after start experiment. Blood parameters...

Behavioral parameters are reliable and useful operational welfare indicators that yield information on fish health status in aquaculture. However, aquatic environment is still constraining for some solutions based underwater cameras or echo sounder transmitters. Thus, the use of bio-loggers internally externally attached to sentinel emerges as a solution monitoring tanks- sea cages-rearing systems. This review focused recently developed AEFishBIT, small light data storage tag designed be...

Behavioural monitoring can provide crucial information on welfare and feeding in aquaculture. Passive acoustic of behaviour be particularly useful recirculating aquaculture systems (RAS), as they often have turbid water that impairs visual monitoring. Currently, little is known about the sounds make up soundscapes RAS tanks holding Atlantic salmon (Salmo salar). In this study, hydrophones were used to continuously record soundscape eight single tank parr for 15 days, with fish four being...