Bjørn-Steinar Sæther

• Dr. Scient. / PhD
• Professor at UiT The Arctic University of Norway

Coastal aquaculture and local fisheries interact in shared marine environments, influencing each other synergistically and/or antagonistically. Salmon farming, notably with open-net sea cages along the Norwegian coast, attracts wild fish due to increased food availability from uneaten feed, but it also exposes wild fish to farm emissions like waste...

Aquaculture provides an important and expanding source of protein rich and healthy food to the world. However, to minimize environmental harm from aquaculture, interactions with wild fish communities need to be thoroughly assessed. Here, we characterize the existing knowledge pertaining to such interactions, exemplified with Atlantic salmon ( Salmo...

Pollock Pollachius virens modify their feeding habits when including in their diet uneaten feed pellets from salmon aquaculture sea cages. To determine the influence of salmon farms on Pollock, multivariate and univariate analyses were conducted on the trace element signatures from muscle and liver tissues. Sample fish were caught in the vicinity o...

In the present study, nutritional profiling of the alternative main protein sources (AMPs) such as shellfish waste, fish offal and by-catch were carried out to evaluate the possible role to replace the fishmeal in the diet. Five diets were prepared with 40% (by weight) dried filtrate of autolyzed prawn and crab wastes (Diet A), dried fish offal (Di...

There is a growing interest in cod farming, this time with a domesticated farmed cod that will have characteristics that differ from wild cod. There is a need for an updated knowledge base on the risk of impact on wild cod, especially genetic and ecological interactions and localization in relation to spawning and on-growing areas. This report, whi...

Capture-based aquaculture (CBA) combines aquaculture practices with capture fisheries to keep the catch alive for either short or long periods of time, for feeding or for live storage. CBA enables us to market numerous species ranging from molluscs, scallops and crustaceans to fish such as tuna, cod, eel and groupers. In CBA, handling and adaptatio...

When fish are reared for food production in aquaculture, they can be held in different types of rearing systems and subjected to various husbandry routines and operations. Each of these systems or operations can present different welfare risks to the fish, which in turn are dependent upon both the species and its life stage. In this chapter, we add...

Salmon farms attract large amounts of wild fish, which prey on uneaten feed pellets. The modified diet of the wild fish aggregating at salmon farms may reduce the flesh quality of the fish, influencing the local fisheries. We compared the quality of saithe (Pollachius virens) captured near (farm associated—FA) or more than 5 km away (un‐associated—...

The snow crab (Chionoecetes opilio) is an invasive species new to the Barents Sea that expands its geographic range by larval drift and adult migration. To evaluate the potential spreading of the species in the Barents Sea, we investigated temperature selection and the final thermal preferendum (FTP) of nine adult males in a free choice horizontal...

Mean lengths of newly hatched cod larvae from egg incubation at 4 °C (Low-L) and 9.5 °C (High-H) were similar, and only minor differences were observed in larval histomorphology. However, growth performance of larvae reared at 4 °C (T1-LL) and 9.5 °C (T2-LH) from the 4 °C egg incubation and 4 °C (T3-HL) and 9.5 °C (T4-HH) from the 9.5 °C incubation...

In a study between October and November 2015 in northern Norway, bait prepared from the by-product of the shrimp and snow crab industry was employed in the pot fishery to capture cod and saithe. Frozen natural herring was used as control bait. Pots with the three bait types were placed 1,000 m apart in order to eliminate the risk of interaction bet...

This study investigates the effects of temperature on the survival, food intake, oxygen consumption and growth during long-term live holding of captive male snow crab (Chionoecetes opilio) (average = 0.7 kg). The crabs were held at three different temperatures, 3, 6 and 9°C. The trials were done using groups of snow crabs held in nine land-based ho...

In this study, we investigated the behaviour of Atlantic cod (Gadus morhua) toward three commercially available protein hydrolysates made from shrimp (Pandalus borealis), blue mussels (Mytilus edulis) and capelin (Mallotus villosus), and used blank (seawater) as control. The shrimp and blue mussel attractants were based on industrial waste products...

The Arctic charr (Salvelinus alpinus) is a relatively stenothermal fish that displays a high degree of biological plasticity. Although primarily a freshwater fish, there are anadromous populations at the northernmost limits of the distributional range. Developmental plasticity has both advantages and disadvantages for establishment in culture, with...

Forprosjektet er et oppdrag fra FHF som hadde til hensikt å belyse bruken av not som redskap for fangst av torsk (og hyse) levende til fangstbasert akvakultur (FBA). Rapporten oppsummerer næring- og forskningserfaring med notfangst av torsk og hyse fra 1950-tallet og frem til i dag. Snurpenot og ringnot er skånsomme redskap, men torsk og hyse gjenn...

Forprosjektet er et oppdrag fra FHF som hadde til hensikt å belyse bruken av not som redskap for fangst av torsk (og hyse) levende til fangstbasert akvakultur (FBA). Rapporten oppsummerer næring- og forskningserfaring med notfangst av torsk og hyse fra 1950-tallet og frem til i dag. Snurpenot og ringnot er skånsomme redskap, men torsk og hyse gjenn...

Forprosjektet er et oppdrag fra FHF som hadde til hensikt å belyse bruken av not som redskap for fangst av torsk (og hyse) levende til fangstbasert akvakultur (FBA). Rapporten oppsummerer næring- og forskningserfaring med notfangst av torsk og hyse fra 1950-tallet og frem til i dag. Snurpenot og ringnot er skånsomme redskap, men torsk og hyse gjenn...

A metabolomics approach was used to analyze effects of salmon farming on wild saithe (Pollachius virens) populations. Saithe fish were captured at two salmon farms and at two control locations around the island Hitra, Norway. At each location the fish were captured with either benthic gillnets and automatic jigging machines. Changes in diet seem to...

As increasing amounts of novel raw materials are used in aquafeed production, it is important to measure their quality against existing ingredients and their effects upon production strategies. A first step to achieving this goal begins with an improved understanding of the underlying growth potential of each farmed species across a range of dietar...

Seasonal growth patterns have been investigated in juveniles of two reproductively isolated Arctic charr [Salvelinus alpinus (L.)] morphs, which coexist in distinct ecological niches (upper-water and deep-water environments) in a subarctic lake. Offspring (F1-generation) of each of the littoral spawning charr (LO) and the profundal spawning charr (...

AimA focal task for invasion biology is to identify the environmental variables and biological traits that set and underpin realised and potential habitats of invasive species. Ecophysiology provides powerful empirical knowledge that connects theory with natural phenomena and may improve the accuracy of species distribution modelling. We used the i...

Saithe Pollachius virens are attracted to uneaten salmon feed underneath cages at open‐cage salmon farms in Norway. The aggregated Saithe have modified their feeding habits as they have switched from wild prey to uneaten food pellets, which could lead to physiological and biochemical changes in the Saithe. Variations in profiles of total lipids, fa...

Salmonid farming affects both the environment and other industries, with impacts of wild fish attracted to fish farms being a major concern. Here, we summarized existing knowledge on the impacts of such aggregations around open-cage salmonid farms in Norway on the environment and human activities and on the interactions of these impacts. Waste fish...

Temperature preference of juvenile (age 1+) Arctic charr (Salvelinus alpinus L.) originating from four arctic and sub-arctic populations (Svalbard and mainland northern Norway), representing a range of habitats with different temperature conditions, was studied by use of a shuttle-box system which allowed individual fish to control their environmen...

Juvenile green sea urchins, Strongylocentrotus droebachiensis, with an initial mean test diameter of 9.5 mm (±1.2 SD) were held in the laboratory, in individual compartments and at constant temperatures (8.5 C) (n = 90) for a period of 99 wk. The animals were supplied with flow-through sea water, and fed the Nofima sea urchin manufactured feed ad l...

This article describes the status of the Arctic charr (Salvelinus alpinus L.) aquaculture industry in Iceland, Norway and Sweden. The purpose of the work was to give an update on the status of Arctic charr farming in these countries based on information obtained from the industry itself. The data were collected using questionnaires designed for the...

The effects of three different temperatures on the growth and maturation of the offspring of cultured versus wild populations of juvenile arctic charr (Salvelinus alpinus L.) were investigated. The fish (start weight 17 g) were reared for 5 months at constant temperatures of 12, 14 and 16°C under a continuous light regime (LD24:0). Growth performan...

The effect of three different temperatures on growth in a first progeny generation, hatchery reared, subarctic population of European whitefish (Coregonus lavaretus L.) were investigated. The whitefish (start weight 444 g, ±SD 125 g) were reared for 60 days at three constant temperatures; 15, 18 and 21°C and under ambient light regimes for 70°N lat...

Juvenile green sea urchins, Strongylocentrotus droebachiensis ranging in size from 0.1 to 30 g were held in individual compartments at four constant temperatures (6, 10, 12 and 14 °C) (n = 54 per temperature treatment) for a period of 100 days. Growth, survival, feed intake and feed conversion ratio (FCR) of the urchins were monitored during this p...

During rapid decompression in the course of fish capture, cod (Gadus morhua L.) is unable to reabsorb excess gas in the swimbladder sufficiently rapidly, and the bladder ruptures as the gas expands. In capture-based aquaculture (CBA), knowledge of the severity of the rupture stress is required. The objective of this study was to describe the swimbl...

The ACE inhibitory activity of a desalted protein hydrolysate from Northern shrimp (Pandalus borealis) was studied. Measurements by two independent methods both revealed higher in vitro ACE inhibitory activity, IC50=0.075 and 0.035mg/ml, respectively, than earlier reported in comparable hydrolysates. Two novel ACE inhibitory tri-peptides, Phe-Thr-T...

Recirculating aquaculture systems (RAS) are increasingly being used in salmon producing countries such as Norway and Chile (Del Campo et al, 2010). In well-functioning RAS, nitrite (NO2-) is converted to nitrate relatively quickly in biofilters. However, when biofilters are operated outside optimal ranges of e.g. pH, alkalinity, or feed loading, th...

Fish can be the recipients of numerous injuries that are potentially deleterious to aquacultural production performance and welfare. This review will employ a systematic approach that classifies injuries in relation to specific anatomical areas of the fish and will evaluate the effects of injury upon production and welfare. The selected areas inclu...

Growth, feed intake and maturation were monitored in a fast-growing benthivore morph of European whitefish [Coregonus lavaretus (L.)] held under constant light (LD 24:0) and temperature conditions (10°C) for 415 days. Their growth was best described by polynomial regression model and no indication of seasonal patterns (e.g. winter depression) in gr...

POSTER PRESENTATION. The SmartTag (ST) is a miniature acoustical electronic fish tag which by means of a 3 mm outer diameter plastic tube extending from the tag and into the fish buccal cavity, provides measurements of pressure changes associated with breathing (gill ventilation) in free-swimming fish independent of fish swimming depth. Two version...

In Norwegian. English and Norwegian summary.

Use of coldwater recirculating aquaculture systems (RAS) are still very rare in Norway, and only two farms are producing Arctic charr. This project took place in one of these commercial Arctic charr farms; Villmarksfisk AS in Bardu, Northern Norway.The farm gets its make-up water from ground water that holds 5 °C year around. Temperature in the rea...

The growth performance of Arctic charr of wild (W) and hatchery (H) origin was compared in a commercial coldwater recirculation system (Villmarksfisk, Bardu, 68°N, 19°E, Norway). The initial individual body mass was 115g and similar between groups. The rearing temperature was 9.2°C and the fish were held under continuous light (24:0 L:D). At the en...

This study investigates how simulation of condensed winter light conditions effects the growth of wild caught Arctic charr (Salvelinus alpinus L.) held in culture. After capturing from Altevatn, Northern Norway, juvenile Arctic charr were cultivated and subsequently individually divided into two groups. The fish were held under identical conditions...

In several areas along the Norwegian coast local fishermen claim that wild migrating Atlantic cod (Gadus morhua L.) have changed their spawning migratory behaviour following establishment of salmon farms, and no longer enter their natural spawning grounds in the fjords. This has created a heated debate in Norway and, in some areas, passed down a mo...

The influence of dietary fish and plant oils on fatty acid compositions of Atlantic cod tissues was examined to test whether modulation of fatty acid profile following a dietary change differs between lipid-poor (fillet) and lipid-rich (liver) tissues. A dilution model [Robin, J.H., Regost, C., Arzel, J., Kaushik, S.J., 2003. Fatty acid profile of...

This study aimed to investigate the effect of different feeding regime in relation to constant light regime on growth and feed intake among juvenile Atlantic cod. Three experimental groups (duplicated) were held under LD12:12 photo period and constant water temperature (12 °C) for six months. All groups were fed daily in excess using three differen...

Feed intake, body growth, and gonad growth of adult green sea urchin Strongylocentrotus droebachiensis were investigated at a constant temperature (10 °C) and a simulated natural photoperiod (70 °N) for 848 days. Three size groups of sea urchins with an initial test diameter of 30–40 mm (small, S, N=32), 40–50 mm (medium, M, N=36), and 50–60 mm (la...

Local fishermen in several areas of Norway assert that salmon farms have caused the wild migrating cod to change their migratory behaviour, so that they no longer enter their natural spawning grounds in the fjords. If the asserted changes in behaviour of wild cod populations can be linked to establishment of salmon farms, water-soluble odorants are...

The effects of nitrite concentration on growth and feed intake in juvenile cod, Gadus morhua, were examined. In the experiment, juvenile cod with a mean (S.D.) live weight of 7.0 (1.9) g were exposed to four concentrations of nitrite [0, (control), 1.0 (low), 2.5 (medium) and 5 mg NO2–N l− 1 (high)] for 96 days at 8.0 °C, salinity 33 ppt and pH 8.0...

Immature male and female and maturing male Arctic charr Salvelinus alpinus were held at constant temperature (4° C) under either simulated natural photoperiod (nLD) or constant photoperiod (12:12 LD) conditions, and feed intake and growth were monitored at monthly intervals over 13 months. Food was supplied in excess during a 5-h period each day, a...

The effects of chronic un-ionised ammonia (UIA-N) exposure on growth and food conversion efficiency in juvenile Atlantic cod, Gadus morhua, were examined. Fish with a mean (SD) initial weight 16.7 (3.4) g were exposed to four concentrations of UIA-N, ranging from 0.0005 mg l−1 (control) to 0.17 mg l−1, for 96 days at 13 °C. Compared to the control,...

Abstract The influences of dietary fat concentration on growth and energy deposition were studied in two replicated groups of turbot, Scophthalmus maximus (L.). Individually tagged turbot (202.3 g) held at 15.6 °C were offered dry pellets in excess. These contained either high-fat (25.4%) or low-fat (16.6%) concentration and identical protein (43.2...

Effects of photoperiod manipulation on the development of seawater tolerance were studied in Arctic charr. Three groups of fish, previously reared under natural photoperiod and ambient water temperature conditions, were subjected to a constant short daylength, 4L:20D, from 21 December to 30 January, followed by exposure to either 4L:20D, continuous...

Gastrointestinal evacuation of inert particles was monitored in the polar cod Boreogadus saida (Lepechin), held at a temperature of 0.5 degrees C. Fish (31.8 g +/- 0.8 SD) were fed a moist diet, based on natural prey items, containing a particulate marker. Evacuation of marker from the gastrointestinal tract started 48 h after ingestion of a meal....

Abstract Feed intake and growth were studied in groups of turbot fed daily rations of 0.25%, 0.38% and 1% of body weight day–1 for 41 days. Then, all groups were fed 1% of body weight day–1 for the next 34 days. The two restricted rations resulted in reduced growth rates (30% and 60% of fully fed controls), and there was a tendency for increased gr...

Gastrointestinal evacuation of inert X-ray dense marker by turbot, Psetta maxima, was followed by use of radiography. Groups of individually tagged turbot aged 1 + years (136.5 g), were held at 16 degrees C and acclimatized to a feeding period of 4 hours per day. Fish were fed on pelleted feed in excess. The experimental design allowed a test of th...