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Spawning manipulation, broodfish diet feeding and egg production in farmed Atlantic salmon
Full text linkAtlantic salmon aquaculture relies on continuous supply of high quality eggs. Broodfish nutrition and manipulation of ovulation time (photoperiod and temperature) are key factors. The optimum feeding period with broodfish diet has not been investigated before. The present study examined how feeding period with broodfish diet (9 vs. 17 months) interacted with manipulation of ovulation time (early (Nov), normal (Dec), late (Feb)) on broodstock egg production capacity and egg quality in two-sea-winter female Atlantic salmon (∼12 kg). All groups were fed until June 2021 when they were transferred to tanks and starved until ovulation.publishedVersio
The impact of advection on a Subarctic fjord food web dominated by the copepod Calanus finmarchicus
Full text linkpublishedVersio
Genetics in the ocean’s twilight zone: Population structure of the glacier lanternfish across its distribution range
No full textDataset for "Genetics in the ocean’s twilight zone: Population structure of the glacier lanternfish across its distribution range", published in Evolutionary Applications, a Wiley journal
The information deposited consists of two excel files:
1. Benthosema_SNP markers.xlsx. This file contains three spreadsheets:
a. Benthosema_Potential SNPs: A set of 128 potential loci were identified for greater argentine. SNP identification together with flanking sequence is provided for each marker. The SNP to be genotyped is identified within brackets.
b. SNPs distribution in multiplex: Markers were distributed into six multiplex reactions (W1 to W6).
c. Reaction conditions: Primers were developed for the potential SNPs and reaction conditions are specified.
2. Benthosema_ Data.xlsx. This file contains all the available data for the 1288 individuals typed at 121 SNP loci and distributed across 16 sampling sites. Information consists of: Individual identification (ID), Sample (geographic sampling site), habitat (Ocean, Fjord, Mediterranean), coordinates (latitude and longitude), fishing gear, fork length (mm), type of SV (AA, AB, BB), haplotypes, and genotype. Coding of genotypes is as follows: 1 (A), 2 (C), 3 (G), 4 (T) and 0 (missing data). Note that length data was not available for the individuals sampled in the West Mediterranean and it is noted as n.a
Fish investigations in the Barents Sea Winter 2023
Full text linkPreface Annual catch quotas and other regulations of the Barents Sea fisheries are set through negotiations between Norway and Russia. Assessment of the state of the stocks and quota advice are given by the International Council for the Exploration of the Sea (ICES). Their work is based on survey results and international landings statistics. The results from the demersal fish winter surveys in the Barents Sea are an important source of information for the annual stock assessment. The development of the survey started in the early 1970s and focused on acoustic measurements of cod and haddock. Since 1981 it has been designed to produce both acoustic and swept area estimates of fish abundance. Some development has taken place since then, both in area coverage and in methodology. The development is described in detail by Jakobsen et al . (1997), Johannesen et al . (2009) and in Appendix 3, and the current survey design and methods for survey index calculation are presented in Appendix 2. The survey manual is available at the internal IMR quality portal here. At present the survey provides the main data input for several ongoing projects at the Institute of Marine Research, Bergen: monitoring abundance of the Barents Sea demersal fish stocks mapping fish distribution in relation to climate and prey abundance monitoring food consumption and growth estimating predation mortality caused by cod This report presents the main results from the surveys in January-March 2023. The surveys were performed with the Norwegian research vessels “Kronprins Haakon” and “Johan Hjort”, and the Russian research vessel “Vilnyus”. Annual survey reports since 1981 are listed in Appendix 5, and names of scientific participants in 2023 are given in Appendix 4.Fish investigations in the Barents Sea Winter 2023publishedVersio
Dietary electrolyte imbalance alters drinking rate and gastrointestinal tract water fluxes of Atlantic salmon (Salmo salar) smolt in seawater
Full text linkIt was hypothesized that dietary electrolyte balance (dEB) would influence the dynamics of water, ions, and nutrient fluxes in the gastrointestinal tract (GIT) of Atlantic salmon (Salmo salar) smolts differently depending on water salinity. To date, a comparative study on how dEB alters these dynamics in freshwater- and seawater-adapted fish is lacking. The test diets were low versus high dEB (−100 versus 500 mEq kg−1 DM−1) and the test water salinities were 0 versus 30 ppt. Furthermore, the effect of the interaction between dEB and salinity on blood pH and osmolality were investigated. The experiment lasted for 6.5 weeks. Chyme was collected from four GIT segments (stomach, proximal, middle, and distal intestine) and analysed for dry matter (DM), pH, osmolality, crude protein, and ion (Ca2+, Mg2+, Na+, and K+) content. Water, ion, and nutrient fluxes were measured using yttrium oxide (Y2O3) as an inert marker. It was found that there was a diet effect on chyme pH in the stomach, being lower in fish fed the low dEB diet than the high dEB diet. Furthermore, the diet altered ion and nutrient fluxes in the stomach. Water salinity had the largest effect on chyme pH in all the GIT segments and on chyme osmolality in the stomach, which significantly increased in seawater conditions. The interaction between dEB and salinity had an effect on chyme DM, water and ion fluxes in the stomach, proximal and middle intestine. Our results showed that, depending on water salinity, dEB altered water fluxes differently. In freshwater-adapted fish, water influx to the stomach was higher in fish fed the high dEB diet than the low dEB diet, but the difference was neglectable. In contrast, in seawater-adapted fish, water influx into the stomach and proximal intestine was higher in fish fed the low dEB than the high dEB diet, and the amplitude was much larger. Additionally, in seawater conditions, drinking rate was 50% higher in fish fed the low dEB diet (3.07 ml kg−1 h−1) than the high dEB diet (2.04 ml kg−1 h−1). As a result, it was concluded that, in seawater conditions, a diet with a low dEB has a higher flux of water in the stomach and proximal intestine of Atlantic salmon smolts as well as enhanced drinking rate.publishedVersio
Rømt og vill fisk i Etneelva 2023 - Resultat fra Fjord- og Elvelaboratoriet i Etne
Full text linkHovudfokus ved feltstasjonen i Etne er miljøeffektar av havbruk, som genetisk påverknad frå rømt oppdrettslaks, lakselus og virussmitte. I 2023 vart fiskefella i Etneelva sett i drift 11. april og registreringa pågjekk til 8. november. Det var noko redusert fangseffektivitet i løpet av sesongen pga høg vassføring. I tilsaman 9 driftsdøgn (4% av driftstida) var fangsten i fella redusert pga høg vassføring. Tilsvarande reduksjon i fangsteffektivitet har vi også hatt i tidlegare år med 12 driftsdøgn (6% av driftstida) i 2022 og 9% i 2021. Fyrste villaks blei registrert i veke 19 og fyrste rømling i veke 29. I alt vart 2684 fiskar handtert på fella i 2023, mot 4063 i 2022, 3746 i 2021, 5093 i 2020 og 2693 i 2019. Av dei registrerte fiskane var 1095 villaks,1543 sjøaure, 23 pukkellaks og 23 rømte laks. I 2023 hadde 50% av villaksen vandra opp pr. veke 29, ni veker tidlegare enn rømlingane. Som tidlegare år dominerte storlaksen tidleg i oppvandringa medan terten dominerte i slutten av oppvandringsforløpet. For rømlingane registrert på fella varierte storleiken frå 0,59 kg til 6,31 kg, med ei overvekt av individ på 1,0 til 3,0 kg. Skjellkontrollen stadfesta oppdrettsbakgrunn til alle dei registrerte oppdrettslaksane. Av dei 23 registrerte rømlingane på fella, var 39% kjønnsmodne og 61% umodne. Gjennom uttaksfisket om hausten nedstraums fella i sone 1 og 2, vart det fanga 15 oppdrettslaksar. Av dei vart 2 (13%) klassifisert som modne, 13 (87%) vart klassifisert som umodne. Frå sportsfisket blei det rapportert inn 3 oppdrettslaksar nedstraums fella. Av dei 3 rapporterte rømlingane nedstraums, vart to verifisert ved skjellkontroll, og ein vart vurdera som villaks. I dei resterande skjellprøvane frå sportsfisket nedstraums fella, blei det ikkje oppdaga flerie rømlingar. I skjellmaterialet av villaks teke i fiskefella er det heller ikkje funne flerie rømlingar. Basert på registreringane i fiskefella og rapporteringar av sportsfisket i Elveguiden, er andel rømt fisk i 2023 redusert frå 2,1 % til omlag 0 %. Rundt 10 personar var i større eller mindre grad engasjert på fella og Havforskingsinstituttet sitt budsjett for drifta var ca 4 mill kroner med tillegg på 0,5 mill kroner frå OURO. Feltstasjonen i Etneelva framstår no som eit av dei mest nøyaktige målepunkta i Europa for rømt oppdrettsfisk, villaks og sjøaure. Med utgangspunkt i merksemda som feltstasjonen i Etneelva har fått i forskings- og forvaltingsmiljøa, er det etablert ei referansegruppe for Fjord- og elvelaboratoriet for å bidra til kunnskapsdeling og -utvikling og sikra best muleg utnytting av data, materiale og ressursar.Rømt og vill fisk i Etneelva 2023 - Resultat fra Fjord- og Elvelaboratoriet i EtnepublishedVersio
Effects of capture-related stress and pre-freezing holding in refrigerated sea water (RSW) on the muscle quality and storage stability of Atlantic mackerel (Scomber scombrus) during subsequent frozen storage
Full text linkCrowded (stressed) and unstressed Atlantic mackerel with or without pre-freezing holding in refrigerated sea water (RSW) were stored at −19 °C for ∼12 months and analysed for nucleotide degradation (K value), muscle pH, water holding capacity (WHC), fillet firmness, cathepsin B/L like activity, lipid oxidation and fillet colour. The frozen storage showed the largest and most consistent direct effects on the quality metrics leading to increased lipid oxidation, discolouration (yellowing) and reduction on WHC and cathepsin activity. RSW treatment promoted nucleotide degradation and reduced WHC and fillet firmness in interaction with frozen storage and affected fillet colour lightness and saturation. Although showing only marginal main effects, crowding stress modified WHC, cathepsin activity and fillet firmness and colour through significant interactions with the frozen storage and RSW treatment. Further studies with larger sample sizes would be needed to elucidate their complex effects and interactions on the quality and storage stability of mackerel.Effects of capture-related stress and pre-freezing holding in refrigerated sea water (RSW) on the muscle quality and storage stability of Atlantic mackerel (Scomber scombrus) during subsequent frozen storagepublishedVersio
The role of multiple vitellogenins in early development of fishes
Full text linkFunctions of vitellogenins have been in the limelight of fish reproductive physiology research for decades. The Vtg system of acanthomorph teleosts consists of two complete forms of Vtgs (VtgAa and VtgAb) and an incomplete form, VtgC. Insufficient uptake and processing of Vtgs and their yolk proteins lead to inadequate oocyte hydration ensuing failure in acquisition of egg buoyancy and early developmental deficiencies. This review presents a summary of our studies on utilization of multiple Vtgs in species with different egg buoyancy characteristics, as examples. Studies of moronids revealed limited degradation of all three forms of lipovitellin heavy chain derived from their three respective forms of Vtg, by which they contribute to the free amino acid pool driving oocyte hydration during oocyte maturation. In later studies, CRISPR/Cas9 was employed to invalidate zebrafish type I, type II and type III Vtgs, which are orthologs of acanthamorph VtgAa, VtgAb and VtgC, respectively. Results revealed type I Vtg to have essential developmental and nutritional functions in both late embryos and larvae. Genomic disturbance of type II Vtg led to high mortalities during the first 24 h of embryonic development. Despite being a minor form of Vtg in zebrafish and most other species, type III Vtg was also found to contribute essentially to the developmental potential of zebrafish zygotes and early embryos. Apart from severe effects on progeny survival, these studies also disclosed previously unreported regulatory effects of Vtgs on fecundity and fertility, and on embryo hatching. We recently utilized parallel reactions monitoring based liquid chromatography tandem mass spectrometry to assess the processing and utilization of lipovitellins derived from different forms of Vtg in Atlantic halibut and European plaice. Results showed the Lv heavy chain of VtgAa (LvHAa) to be consumed during oocyte maturation and the Lv light chain of VtgAb (LvLAb) to be utilized specifically during late larval stages, while all remaining YPs (LvLAa, LvHAb, LvHC, and LvLC) were utilized during or after hatching up until first feeding in halibut. In plaice, all YPs except LvHAa, which similarly to halibut supports oocyte maturation, are utilized from late embryo to late larval development up until first feeding. The collective findings from these studies affirm substantial disparity in modes of utilization of different types of Vtgs among fish species with various egg buoyancy characteristics, and they reveal previously unknown regulatory functions of Vtgs in maintenance of reproductive assets such as maternal fecundity and fertility, and in embryonic hatching. Despite the progress that has been made over the past two decades by examining multiple Vtgs and their functions, a higher complexity of these systems with much greater diversity between species in modes of Vtg utilization is now evident. Further research is needed to reveal novel ways each species has evolved to utilize these complex multiple Vtg systems and to discover unifying principles for this evolution in fishes of diverse lineages, habitats and life history characteristics.publishedVersio
Long-term climatological trends driving the recent warming along the Angolan and Namibian coasts
Full text linkThe coastal regions off Angola and Namibia are renowned for their highly productive marine ecosystems in the southeast Atlantic. In recent decades, these regions have undergone significant long-term changes. In this study, we investigate the variability of these long-term changes throughout the annual cycle and explore the underlying mechanisms using a 34-year (1982–2015) regional ocean model simulation. The results reveal a clear seasonal dependence of sea surface temperature (SST) trends along the Angolan and Namibian coasts, with alternating positive and negative trends. The long-term warming trend in the Angolan coastal region is mainly explained by a pronounced warming trend in the austral spring and summer (November-January), while the decadal trend off Namibia results from a counterbalance of an austral winter cooling trend and an austral summer warming trend. A heat budget analysis of the mixed-layer temperature variations shows that these changes are explained by a long-term modulation of the coastal currents. The Angolan warming trend is mainly explained by an intensification of the poleward coastal current, which transports more warm equatorial waters towards the Angolan coast. Off Namibia, the warming trend is attributed to a reduction in the northwestward Benguela Current, which advects cooler water from the south to the Namibian coast. These changes in the coastal current are associated with a modulation of the seasonal coastal trapped waves that are remotely-forced along the equatorial waveguide. These long-term changes may have significant implications for local ecosystems and fisheries.publishedVersio
Unlocking the secret life of blue mussels: Exploring connectivity in the Skagerrak through biophysical modeling and population genomics
Full text linkKnowledge of functional dispersal barriers in the marine environment can be used to inform a wide variety of management actions, such as marine spatial planning, restoration efforts, fisheries regulations, and invasive species management. Locations and causes of dispersal barriers can be studied through various methods, including movement tracking, biophysical modeling, demographic models, and genetics. Combining methods illustrating potential dispersal, such as biophysical modeling, with realized dispersal through, e.g., genetic connectivity estimates, provides particularly useful information for teasing apart potential causes of observed barriers. In this study, we focus on blue mussels (Mytilus edulis) in the Skagerrak—a marginal sea connected to the North Sea in Northern Europe—and combine biophysical models of larval dispersal with genomic data to infer locations and causes of dispersal barriers in the area. Results from both methods agree; patterns of ocean currents are a major structuring factor in the area. We find a complex pattern of source-sink dynamics with several dispersal barriers and show that some areas can be isolated despite an overall high dispersal capability. Finally, we translate our finding into management advice that can be used to sustainably manage this ecologically and economically important species in the future.publishedVersio