Contact person: Carsten Hvingel (carsten.hvingel@hi.no)
Northern shrimp in the Barents Sea constitute a commercially and ecologically important stock that isassessed through the NAFO/ICES Pandalus Assessment Working Group. Although the current assessment model is assumed to perform well and the state of the stock is good, many questions remain around the stock dynamics, the data used as input for the stock assessment, and the assessment model itself. IMR aims to improve the current stock assessment of Barents Sea shrimp by 1) analyzing the spatial dynamics over time, 2) evaluating the estimation methods of key input indices from the commercial fleet and IMR’s ecosystem survey and their effects on assessment estimates, and 3) develop a recruitment index based on time series of length composition. The candidate will contribute by working on one of these questions depending on preference and quantitative skills, providing the basis for improving the assessment of Barents Sea shrimp and our advice. There will be possibilities for participating in relevant fieldwork.
Contact persons: Carsten Hvingel (carsten.hvingel@hi.no), Fabian Zimmermann (fabian.zimmermann@hi.no)
Almost thirty years after a failed fishery that resulted in the collapse of the Iceland scallop stock in the Svalbard area, recent research of IMR shows that the stock has recovered. This provides the opportunity to monitor the unfished stock and establish a basis for future management before a potential reopening of a fishery. Currently, our work focuses on testing and evaluating survey methods and methods for abundance estimation, especially the use of video recordings for determining scallop density. IMR plans to improve the robustness and efficiency of the current approaches to establish routines for surveying and a knowledge base for future stock assessment. The candidate will contribute by evaluating video analysis methods, comparing video and dredge measurements, test approaches to derive shell size from images, and explore effects of survey design on stock estimates. There will be possibilities for participating in relevant fieldwork.
Contact person: Fabian Zimmermann (fabian.zimmermann@hi.no)
The blue mussel (M. edulis) has external fertilization where eggs and sperms are shed directly from the genital ducts into the water column. The fertilized egg undergoes several different larval stages before metamorphosis ends the pelagic life. The larvae growth is affected by temperature, salinity and food ration, and the duration of the pelagic phase is normally between 3 to 5 weeks. Mortality during the larval phase is high, primarily due to predation, but extremes in temperature and salinity and food shortage also contribute. Most bivalve larvae are able to settle when they reach 250 to 300 µm in shell length, yet final settlement may not occur until the post larva reach 2 mm. The larvae show different behavior to different substrates and are understood to be able to discriminate between habitats. Settlement is difficult to measure in the field and is normally inferred from recruitment data post settlement (days to weeks). Little is known on the mortality and growth of post settled mussel in natural habitat. The IMR has started to monitor the abundance of mussels over a fjord to coast salinity gradient. These observations indicate recruitment of mussels to the full gradient, yet adult mussels are mainly observed in the less saline inner and mid-section of the gradient. This point to high mortality of the early life stages of mussels in coastal areas. In this MS thesis we aim to investigate: The colonization, growth and mortality of mussel larva (on natural and artificial substrate?) over a salinity gradient in the intertidal zone, by testing the overall hypothesis:
a. There are no differences in the colonization, growth and mortality of mussel larva (on natural and artificial substrate) over a salinity gradient in the intertidal zone
The master thesis will comprise experimental design, field experiments and data analysis. The following parameters can be collected: Temperature, salinity, seston?, mussel metrics, predators and photos (abundance, size distribution and predators).
The field work will be conducted in two periods with an overall duration of approx. 12-16 weeks:
The MS requires basic marine biological and ecological knowledge.
Contact persons at the HI/IMR: Tore Strohmeier (mob 90720754 / tore.strohmeier@hi.no), Antonio Aguera (mob 94880039)
Mussels are osmoconformers and reside in salinities ranging from 4 psu to fully marine conditions. Mussel feeding rate may be similar for populations living under different salinities, but when transferred to a marked change in salinity the feeding rate drop. The time to acclimate feeding rate (and to recover respiration rate) to control values is dependent on the extent of the salinity change and may exceed several weeks. There is currently a lack of knowledge on the acclimatization of mussel feeding physiology to the natural variation in salinity encountered in estuaries and fjords.
In this MS study we aim to investigate the mussel feeding and respiration rate in a natural environment (e.g. in situ) that inhabit short term fluctuations in salinity. As this experimental approach do not control other environmental factors known to impact mussel physiology (e.g temperature and food) it requires frequent measures of physiological rates and environmental stimuli over several events of stimulus.
The master thesis will comprise experimental design, field experiments and data analysis. The following parameters can be collected: Temperature, salinity, food/seston, physiological rates and mussels.
The field work will be conducted in the inner part of the Hardangerfjord during spring and summer (approx. 10-12 weeks) using the IMR mobile physiological laboratory and instrumentation.
The MS requires statistical background and basic marine biological- and physiological knowledge.
Contact persons at the HI/IMR: Tore Strohmeier (mob 90720754 / tore.strohmeier@hi.no), Antonio Aguera (mob 94880039)
There is a raising interest in understanding the distribution of mussels along the Norwegian coast and assessing the impact of their culture in fjord ecosystems. Modelling the spatial and temporal distribution of adult mussel and their larvae is key to understand the impact of blue mussels in fjord ecosystem. To obtain realistic models we need to understand mussel larval physiology, how long the larvae stays in the water column, how are the natural low seston conditions and physicochemical temporal and spatial gradients affecting the larval development and their potential distribution and competition with other important zooplankton species.
We have some knowledge already on mussel larval development, the role of food, and other environmental conditions. However, this information is not sufficient, it is based on laboratory experiments under controlled conditions that limit our understanding of the larvae feeding physiology and development.
This experiment will aim to develop a system to successfully culture larvae in a flow through setup using natural seston as food and exposing larvae to natural variations of food and physicochemical seawater parameters (temperature, salinity and pH) during a full mussel reproductive season. Other factors such as maternal provisioning and how it changes during the reproductive season may be considered.
The master thesis will comprise the formulation of specific hypothesis related to larval developmentof blue mussels, experimental design, take of measurements, data processing and statistical analyses. Experiments lasts from 3-6 weeks plus analyses, several experiments to focus on different hypothesis can be run during the reproductive season between May-August.
The MS requires basic marine biological- and physiological knowledge, life history of marine invertebrates and basic statistical skills
Contact persons at HI/IMR: Tore Strohmeier (mob 90720754; tore.strohmeier@hi.no) / Antonio Aguera (mob 94880039)
The IMR has started to monitor the abundance of mussels over a fjord to coast gradient. These observations indicate recruitment of mussels may be happening along the whole shoreline, however stablished populations with several year classes are patchy. The monitoring effort initiated by IMR already comprises the assessment of presence/absence of mussels, cohort presence and other qualitative metrics of abundance at randomly selected stations along the fjord shoreline. An effort that will be continued during the coming year.
Species distribution models (SDM) has proven a valuable tool to describe, predict and find drivers of species distributions. These models use of the concept of fundamental niche to assess the ranges and combinations of environmental (biotic and abiotic) that drives the observed patterns to predict the potential distribution of the species within the area of study.
In this MS, the student will analyze and develop SDMs for the blue mussels in Hardangerfjord, using the data gathered during the mussel monitoring program and diverse sources of spatial information on the Hardangerfjord environmental conditions (physical: depth, slope, temperature, salinity and biotic: primary production) The MS requires basic GIS skills and statistical analyses of spatial data using R.
Contact persons at HI/IMR: Tore Strohmeier (mob 90720754; tore.strohmeier@hi.no) / Antonio Aguera (mob 94880039)
Kontaktperson: Jane Godiksen (jane.godiksen@hi.no)
Fish populations respond to food availability, but it can be difficult to evaluate exactly what the food available to any given species is without detailed ecosystem modelling. Food limitation is often modelled using “Density Dependence”, where food availability declines as predator biomass increases, but this makes a highly simplistic assumption that the food availability is constant. Simply adding up the biomasses of all the available food species is not sufficient to represent food availability, because some food is preferred to others and the fraction of the available prey that is eaten is highly variable between food species. This project will therefore construct a proposed simplified “Available Food Index” for a number of major fish stocks in the Barents and Norwegian Seas, and investigate if this index is useful index for tracking the development of the predator fish.
Ideally one would construct such an index using the annual biomass of each prey and the annually varying preference for each prey. However this annually varying prey preference data is rarely available, although long term averages can be obtained. The simplified available food index will therefore be constructed using the time series of biomass for the different food sources from stock assessment and survey data. This will then be modified by a time averaged prey preference in order to weight the different prey species appropriately. The project will then compare the Available Food Index with the development of the stocks, both in terms of overall population biomass and the individual size and condition of the fish, in order to test if this has potential to be a useful index. If time allows the work could be extended in several ways. Information to construct such an index is available from the existing Atlantis ecosystem model in the Barents and Norwegian seas, and it would be valuable to compare the data- and model- derived indices. There is also a possibility for international collaboration, with data available to construct similar indices in United States fisheries.
Data to construct such indices are available in many ecosystems, but such indices are not currently in use. It could therefore be expected that if the index does track some features of stock development then this would form the basis of a scientific publication. The aim would be to present the project at the annual ICES annual science conference (held in September each year), and funding will be available to support this.
The project would primarily require an interest in fisheries biology and ecology, detailed statistical or modelling knowledge is not required.
IMR supervisor: Dr. Daniel Howell (daniel.howell@hi.no) .
UIB supervisor: TBD
Contact person: Frithjof Moy (frithjof.moy@hi.no)
The MAREANO programme has been collecting video of the offshore seabed since 2006, identifying species and habitats, and recording the occurrence of juvenile species along the way (invertebrates and fish). However, the records of juveniles remain unused in our analyses, offering an opportunity to explore this data for the first time. There are habitats, abiotic variables and species data offering a chance to identify associations using multivariate statistics/modelling approaches. Nursery habitats are of particular conservation relevance and are therefore important to identify and flag to marine managers nationally and internationally.
Location: Suits Bergen-based Masters students.
Are you interested - contact: Rebecca Ross (Rebecca.Ross@hi.no)
The MAREANO programme develops offshore benthic habitat maps relevant to Norwegian offshore marine management needs. With records of invertebrate taxa, fish taxa, associated habitats, and abiotic conditions, there is a lot of room for the exploration of fish/habitat associations which could provide useful knowledge to marine managers interested in supporting the fishing industry whilst balancing conservation needs.
Location: Suits Bergen-based Masters students.
Are you interested - contact: Rebecca Ross (Rebecca.Ross@hi.no)
The mapping of vulnerable benthic habitats (e.g. coral reefs, sponge aggregations, sea pen fields) is of particular interest to marine managers who are responsible for ensuring appropriate conservation actions are taken. However, observation records are not always enough to judge how big a patch is likely to exist. While modelling methods are already used in MAREANO to offer best guesses as to offshore vulnerable habitat extent, the MAREANO video database offers a wealth of data to further explore the drivers of patch size and to estimate the natural range of patch sizes that occur for each vulnerable habitat in Norwegian offshore waters. This would help temper national advice and inform international discussions on standards for vulnerable habitat surveys.
Location: Suits Bergen-based Masters students.
Are you interested - contact: Rebecca Ross (Rebecca.Ross@hi.no)
Contact person: Svein Løkkeborg (svein.loekkeborg@hi.no)
Knowledge of fish stock sizes is a key element in sustainable fisheries management. The knowledge is needed to assess the state of the stock, investigate the effects of fisheries and to set future harvest levels. A common way of estimating fish stock size is by acoustic trawl surveys where acoustic energy is converted to fish abundance, with the help of samples of species composition and size distributions from trawl hauls. When schools or aggregations of fish are registered on the vessel mounted echosounder a sample of the fish is usually obtained by trawling. However, it can be difficult to catch the fish with the trawl several hundred meters behind the vessel, especially when fast swimming fish are targeted. Missed catches result in wasted effort and uncertainty in the trawl samples. In this project the aim is to investigate whether catch success can be improved by better control of the trawl position relative to the targeted fish. Fish abundance estimated from acoustic data will be compared with catch size and related to trawl position. For better temporal and spatial resolution catch data will be obtained from a stereo-camera system mounted inside the trawl. The aim is also to investigate whether catch success is affected by species or school specific behaviour. The project is part of a research-based innovation center, CRIMAC (www.crimac.no) financed by the Norwegian Research council. The student will collaborate with other MSc and PhD students in the center. Data for the project were collected in the Norwegian sea ecosystem survey in May 2022 and there will be an opportunity to participate in a future survey for further data collection and for better understanding of the fishing operation and the monitoring methods.
Are you interested - contact: Maria Tenningen (maria.tenningen@hi.no) and/or Nils Olav Handegard (nilsolav@hi.no).
Contact person: Rune Waagbø (Rune.Waagbo@hi.no)
In principle, all our running research projects in the research program can be available for master student studies.
IMR-supervisor: Øystein Sæle (oystein.saele@hi.no)
IMR-supervisor: Øystein Sæle (oystein.saele@hi.no)
IMR-supervisor: Øystein Sæle (oystein.saele@hi.no)
Contact person: Jon Helge Vølstad (jon.helge.voelstad@hi.no)
The IMR run several sampling programs to collect data from commercial fisheries, and provide estimates using a Bayesian modelling framework dependent on several use choices, such as categorization of fishing gears and post-stratification of spatial and temporal covariates. We wish to analyse the roboustness of estimates to user choices and sampling variation. The candidate will analyse results from different model configurations and assess the robustness of estimates and implications for interpretation. Some familiarity with Bayesian statistics and R will be required.
IMR-supervisor: Edvin Fuglebakk (edvin.fuglebakk@hi.no).
Practical constraints commonly lead to deviation from probabilistic approaches in sampling. This can be addressed with explicit modelling approaches, or with post-stratification and assumptive applications of traditional design-based estimators. These approaches come with different formulations of assumptions and different technical implications for estimation support systems. We would be interested in do a comparative study of such estimators for evaluating their practical utility and interpretability for non-probabilistic sampling of biological parameters from commercial fisheries.
IMR-supervisor: Edvin Fuglebakk (edvin.fuglebakk@hi.no).
Different biological variables very different time-cost and monetary cost. Length-measurements are for example very cheap and can be done in field, while age-determination and genetic analysis require the logistics, expertise and material cost associated with post-fieldwork analyses. When estimates are to be delivered on a deadline, time-cost may prohibit complete analysis of the collected data. In these cases, it is a challenge to do post-collection prioritization of which of the collected material to analyze, and ad-hoc solutions may introduce bias in estimates. An ideal procedure would preserve or improve upon the statistical properties of the original sampling while at the same time be implemented within practical logistical constraints. The candidate would analyze sampling designs, workflows and proxy indicators of fishing activity in order to propose a solution for rigorous post-collection subsampling of age-materials.
IMR-supervisor: Edvin Fuglebakk (edvin.fuglebakk@hi.no).
The survey estimates are traditionally used as input to assessment models, but there could be simpler models serving as alternatives to the assessment models, which are worth pursuing.
Suggested contact: Jon Helge Vølstad (jon.helge.voelstad@hi.no)
Kontaktperson: FG-leder Monica Sanden (Monica.Sanden@hi.no)
Want to do your master’s thesis on antibiotic resistance? In collaboration between Institute of Marine Research (IMR) and University of Bergen (UiB).
We have a master’s project in microbiology connected to the Res-Marine project funded by the Norwegian Research Council (NRC) funded (https://www.tv2.no/a/11567134/; https://prosjektbanken.forskningsradet.no/project/FORISS/315266?Kilde=FORISS&distribution=Ar&chart=bar&calcType=funding&Sprak=no&sortBy=date&sortOrder=desc&resultCount=30&offset=0&Fritekst=Res-Marine), that aims at understanding the role of the marine environment in dissemination and emergence of antimicrobial resistance (AMR). The student will carry out isolation of bacterial
pathogens from waste water, marine sediments and water samples, and carry out antibiotic susceptibility testing. The tasks would also include learning DNA sequencing and analysis of whole
genome sequences (bioinformatic analysis). If interested contact Nachiket Marathe (nachiket.marathe@hi.no).
Plastic pollution is a global environmental problem that is projected to increase in upcoming decades because of the upward trend in global production and consumption. MPs provide surficial substrates for the microorganisms to attach and form biofilms. Fish pathogens such as Aeromonas spp., Vibrio spp. and opportunistic human pathogens like E. coli are present in biofilms from marine plastics. Recently, previous master student on the project has characterized multidrug resistant pathogens and environmental bacteria present on marine plastics from western Norway, using whole genome sequencing. This work has led to 2 publications (Radisic et al., 2020; Radisic et al., 2021). The master’s project will focus on the role of microplastics in dissemination of antibiotic resistance genes and resistant pathogens in the marine environment. The student will carry out isolation of pathogens, DNA extraction and Whole genome sequence analysis. If interested contact Nachiket Marathe (nachiket.marathe@hi.no).
Contact person: forskningssjef Robin Ørnsrud (Robin.Ornsrud@hi.no, tel. 913 43 345)
In recent years, in the global food market fraud and adulteration is increased violating consumers' safety. The food products available in the market are highly processed; therefore, difficult to identify the species or tissue origin by visual inspection. Molecular tools, i.e., PCR, genome sequencing, barcoding, and proteomics can be used to identify species from highly processed samples. Among the established methods, DNA methods are accurate and precise but unable to identify the tissue origin of the food sample. Our present study will implement an untargeted shotgun proteomics approach for species and tissue authentication from food and feed samples with the spectral library method. The approach is independent of any genomic information and is easy to implement on non-model species lacking such information. To implement this method for routine analyses across various laboratories, we want to create a spectral library database with bioinformatics tools and would like to involve a student with bioinformatics or biotechnology expertise. This database will use a tool to match any given food or feed spectra to all the available libraries and help to identify the origin of the sample. All the required proteomic data is collected by us (Institute of Marine research); libraries were built for sample matching and testing food and feed samples of interest. Making these libraries available online as a database will benefit regulatory agencies to use this approach for routine analyses. Besides authentication, the spectra data from the database can be used to establish a phylogenetic relationship between species by using a direct spectra comparison tool called ‘compareMS2’.
References:
Belghit, I., Varunjikar, M., Lecrenier, M.C., Steinhilber, A., Niedzwiecka, A., Wang, Y.V., Dieu, M., Azzollini, D., Lie, K., Lock, E.J. and Berntssen, M.H.G., 2021. Future feed control–Tracing banned bovine material in insect meal. Food Control, 128, p.108183. https://www.sciencedirect.com/science/article/pii/S0956713521003212
Varunjikar, M.S., Moreno-Ibarguen, C., Andrade-Martinez, J.S., Tung, H.S., Belghit, I., Palmblad, M., Olsvik, P.A., Reyes, A., Rasinger, J.D. and Lie, K.K., 2022. Comparing novel shotgun DNA sequencing and state-of-the-art proteomics approaches for authentication of fish species in mixed samples. Food Control, p.108417. https://www.sciencedirect.com/science/article/pii/S0956713521005557?via%3Dihub
Varunjikar, M. S., Belghit, I., Gjerde, J., Palmblad, M., Oveland, E., & Rasinger, J. D. (2022). Shotgun proteomics approaches for authentication, biological analyses, and allergen detection in feed and food-grade insect species. Food Control, 108888. https://www.sciencedirect.com/science/article/pii/S0956713522000810
Are you interested - contact: Madhushri Shrikant Varunjikar (madhushri.shrikant.varunjikar@hi.no)
Contact person: Rolf Korneliussen (rolf.korneliussen@hi.no)
Anthropogenic noise in the sea is increasing and has been recognized as a pollutant of the sea e.g. under the European Marine Strategy Framework Directive (MSFD). Among the most widespread and long-range sources of underwater sound are seismic air guns, routinely used in the search for, and during exportation of oil and gas reserves. The intense sound exposure at very close range of the air gun can lead to physical injury and death. Beyond such close range, but within hearing range, it can mask important biological sounds such as communication between individuals or sound from an approaching predator or prey. Continuous noise, such as noise from boat engines and oil and windfarm industry may be even more harmful, because it leaves fewer silent periods that could be used for communication. Cod, like other gadoids, produce sounds and use them in a variety of behaviours. They use the sounds for communication, including mating and territorial behaviors. Cod make sounds using striated drumming muscles that attach to the swim bladder. The sound /grunts are made singly, or in a short series, and are produced over the year by females and males, but during spawning mainly by males. In ongoing project at IMR, SpawnSeis, we are looking at the effect of seismic on spawning cod. We additionally have ongoing and planed projects looking at effects of anthropogenic noise from vessels and windfarm industry.
This MSc project will look at data from the SpawnSeis project, where we have recorded the behaviour (sound and video) of spawning cod in a fish-net-pan when exposed to a seismic airgun. In this setup
the cod was also periodically exposed to boat noise between more silent periods. A recent study hypothesis that cod prolong their grunts when exposed to boat noise.
Task:
Method: Analysing vocalisation and behaviour of cod from audio and video recordings, during their exposure to seismic air gun, boat noise and silent periods.
UiB supervisor: Beatriz Diaz Pauli (Beatriz.Diaz-Pauli@uib.no)
Are you interested contact: Karen de Jong (karen.de.jong@hi.no), Anne Christine Utne Palm (annecu@hi.no) or Lise Doksæter Sivle (lise.doksaeter.sivle@hi.no),
Variance estimation of acoustic-trawl and swept-area survey estimates has received increasing attention with the on-going REDUS project (Reduced Uncertainty in Stock Assessment) at the IMR. Using the StoX software, the variance of the survey estimates can be estimated by bootstrapping echosounder and trawl data. This routine has however not been intensively tested with regards to number of bootstrap replicates, number of data points available and the stochastic nature of the data. Evaluating these bootstrap routines and suggesting alternatives would be a valuable contribution to the assessment of fish stocks.
Suggested contact: Espen Johnsen (espen.johnsen@hi.no).
Machine learning initiatives have been initiated at the IMR for categorizing images of fish, seals and other organisms, and similar approaches are intended for acoustic data. Alternatively, traditional image analysis can be applied.
Suggested contact: Nils Olav Handegard (nilsolav@hi.no).
Waves in the ocean does not only occur at the surface. They are also commonly observed in the ocean interior as internal waves and are considered important features for vertical mixing of water masses. For internal waves to exist, the ocean must be stratified. As such, the density must change with depth due to changes in temperature and/or salinity. If the density changes over a small vertical distance (as in the case of the thermocline) the waves propagate horizontally like surface waves, although at slower speeds due to the density difference across the thermocline interface. If the density changes continuously, the waves can also propagate vertically as well as horizontally through the ocean.
Uniformly scattered organisms and particles in the water column can be observed using scientific echosounders. If these scatters are located where internal waves occur, the wave patterns become visible on the echograms. Conversely, if no waves are present, the scatterers will be evenly distributed. The scatterers can then be used to detect internal waves in the water column. The objective of the project is to develop a data mining algorithm that automatically locate the presence of internal waves from acoustic data. The One Ocean expedition are collecting acoustic data around the world, and this data set will be used as test case. IMR has also a large database of historical acoustic data that also can be mined for these features and can be used as a complementary option. The project is associated with the One Ocean expedition (https://oneoceanexpedition.com/), the Center for Research-based Innovation in Marine Acoustic Abundance Estimation and Backscatter Classification (https://crimac.no/) and the Nansen Environmental and Remote Sensing Center.
Are you interested - contact: Nils Olav Handegard (nilsolav@hi.no) and/or Johnny A. Johannessen (johnny.johannessen@nersc.no).
Contact person: Jan Erik Stiansen (jan.erik.stiansen@hi.no)
As part of the international Antarctic krill survey, krill trawls were carried out across the entire Scotia Sea. Sensor mounted on the krill trawls collected temperature and salinity data. Combined with regular CTD casts from research vessels involved in the survey, analysis of this dataset will provide valuable information of the hydrographic conditions during the krill survey, and an update to a similar survey conducted in 2000
Contact person: Angelika Renner (angelika.renner@hi.no)
Working place: Tromsø
During January-February 2019, several combined current profilers/echosounders were deployed for ~1 month in Bransfield Strait. Analysis of this unique dataset will provide insight into dynamic processes contributing to water mass exchange and krill swarming mechanisms in this hotspot for Antarctic krill fisheries.
Contact person: Angelika Renner (angelika.renner@hi.no)
Working place: Tromsø
The Oceanography & Climate Research team at IMR has designed a new regional ocean model based on the NEMO Ocean Engine, a community Ocean Model publicly available (check links below), that represents the thermo-haline dynamics of the Arctic Ocean. This ocean model permits to conduct cool experiments, such as for example study what happens if one increases the river inflow to the Arctic basin. Figure 1 shows what happens if one increases the river inflow to the Arctic basin by 4% over a period of 50 years: the surface salinity of the Arctic Ocean becomes lower in most places, but actually becomes higher in the central region of the Arctic. Why is this possible? How can putting more freshwater lead to areas of higher salinity? What are the implications for the Arctic Ocean in a changing climate? If you like to brainstorm on non-linear problems you can help us answer these questions!!
Links: The NEMO Ocean Engine, an Open Source Ocean Model anyone can download https://www.nemoocean.eu/. An article with detailed results on our Arctic Ocean simulations using the NEMO Ocean Engine https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021JC017270
Reference:
Hordoir, R., Skagseth, R. B. Ingvaldsen, A. B. Sandø, U. L¨optien, H. Dietze, A. M. U. Gierisch, K. M. Assmann, Lundesgaard, and S. Lind (2022), Changes in Arctic stratification and mixed layer depth cycle: A modeling analysis, Journal of Geophysical Research: Oceans, 127 (1), doi:https://doi.org/10. 1029/2021JC017270.
Contact person: Robinson Hordoir (robinson.hordoir@hi.no)
Contact person: Aril Slotte (aril.slotte@hi.no)
Calcified structures such as otoliths and scales are usually used for age reading of fish. Both structures are also used for back-calculations of length-at-age. In Atlantic herring (Clupea harengus), scale size is clearly related to fish length (Smoliński and Berg, 2022). However, this scale size – fish length relationship varies over time and is dependent on environmental factors. For Norwegian spring spawning herring, both structures are used for age reading, but the otolith size – fish length relationship has historically not been used. Since 2021 herring otoliths and scales have been sampled routinely from the same individuals. This will allow us to investigate and compare the growth of both otoliths and scales. The aim is to validate if both calcified structures show similar growth trajectories between years and cohorts.
During this project, you will learn how to apply growth measurements of otoliths and scales typically used for age reading and apply basic back-calculation of growth using both structures (Francis, 1990). This includes both, technical methods like photographing and measuring of growth increments as well as statistical analysis. You might have the possibility to sample your own material during a survey in the Norwegian Sea during summer.
Keywords: herring, growth trajectories, Norwegian Sea, otoliths, scales
References:
Francis, RICC 1990. Back-calculation of fish length: a critical review. J Fish Biol, 36: 883-902.
Smoliński, S, and Berg, F 2022. Varying relationships between fish length and scale size under changing environmental conditions – Multidecadal perspective in Atlantic herring. Ecol Indic, 134: 108494.
Supervisor IMR: Florian Berg, Institute of Marine Research (IMR), Bergen, Norway; telephone: +47 94209887; e-mail: florian.berg@hi.no
Co-supervisor: Arild Folkvord, Department of biological science, University Bergen, Norway; e-mail: arild.folkvord@uib.no
Kontaktperson: FG-leder Kjell Gundersen (kjell.gundersen@hi.no)
Zooplankton data finnes ofte bare oppgitt som fordelt på størrelsesfraksjon 180-1000um, 1000-2000 um og >2000um, og ikke fordelt på art og evt stadie. Om vi feks ønsker å estimere C. finmarchicus biomasse i et datasett, er vi avhengige av mer eller mindre velbegrunnede antagelser om at C. finmarchicus utgjør en gitt fraksjon av zooplankton biomassen i hver størrelsesfraksjon, f.eks. 50, 70 og 0 % i de tre nevnte klassene. Gitt den viktige rollen C. finmarchicus har i økosystemet, og behovet vi modellører har for et estimat av C. finmarchicus biomasse til modellvalidering, har vi et ønske om å forbedre den estimerte C. finmarchicus fraksjonen i hver klasse.
Dette tenkte vi kunne gjøres slik:
Contact: Solfrid Sætre Hjøllo (solfrid.hjollo@hi.no) og Cecilie Thorsen Broms (cecilie.thorsen.broms@hi.no).
Kontaktperson: FG-leder Anna Troedsson Wargelius (annaw@hi.no).
The aim of this MSc project is to understand the signaling pathways that will lead to flatfish swimming behaviour prior eye migration and pigmentation formation under influence of light. The student will use imaging and video analyses for recording fish behaviour and morphological defects (eye and pigmentation) under light regime. He/she will also examine molecular markers involved in eye migration modulation.
Contact: Torstein Harboe (torsteinh@hi.no), Prescilla Perrichon (prescilla perrichon@hi.no), Birgitta Norberg (birgittan@hi.no)
Atlantic halibut oocytes undergo extraordinary hydration during maturation, and halibut eggs exhibit highly variable buoyancy. Egg buoyancy is an important parameter representing egg quality in most marine fishes. The objective of this MSc project is to 1) investigate the involvement of multiple vitellogenins (Vtgs) and the functionality of certain cathepsins (CTS) in the process of maturational yolk proteolysis and oocyte hydration in the Atlantic halibut, and 2) relate them to egg quality. The candidate will utilize molecular, biochemical and immunochemical tools for detection of multiple Vtgs in prehydrated and mature oocytes leading to eggs of different buoyancy grades.
Contact: Birgitta Norberg (birgittan@hi.no); Özlem Yilmaz (ozlem.yilmaz@hi.no)
Contact person: Tore Haug (tore.haug@hi.no)
Kontaktperson: Nils Øien (nils.oien@hi.no).
Contact person: Mette Mauritzen (mette.mauritzen@hi.no).
Innsamlet materiale, men studenten kan bli med på tokt. To oppgaver.
HI-veileder: Tore Johannessen (tore.johannessen@hi.no).
HI-veileder: Anders Jelmert (anders.jelmert@hi.no)
I dette prosjektet kan det bli aktuelt med masterstudenter i flere arbeidspakker.
HI-veiledere: Guldborg Søvik, guldborg.soevik@hi.no, Kjell Nedreaas, kjelln@hi.no; Bérengère Husson, brengere.husson@hi.no og Lis Lindal Jørgensen (lislin@hi.no).
Regime shifts have been reported in many marine ecological systems and appear to be ubiquitous features (Blenckner and Niiranen, 2013; Möllmann et al., 2015). They consist in an abrupt and persistent shift between configurations of the system (i.e. the regimes). Beyond this general definition of regime shift, there are however limited agreement on what regime shifts are and the methods for detection of regime shifts from observations are not always appropriately grounded to the mathematical theory of complex systems. Some argue that apparent regime shifts may simply emerge from systems with non-stationary dynamics or when the dynamics are dominated by coloured noise, without actual shifts occurring (Doney and Sailley, 2013; Overland et al., 2008, 2006). In addition, the evidence for regime shifts in marine ecological systems may be weakened by uncertain data and short time-series.
One challenge is therefore to establish the robustness of regime shift detections for real systems, for which theoretical (mathematical) models rarely exist, and for which data availability is restrained (in time and precision). When working with real world examples of marine ecosystem regime shifts, one can ask: What is the ‘class’ of an apparent regime shift? What is the evidence to support it? Could it have emerged by chance and possibly reflect a non-stationary / coloured noise process?
In the Norwegian Sea, it has been argued that an ecological regime shift occurred in the mid-2000, connecting changes in oceanography, plankton and fish (Vollset et al., 2022). This will be used as a test case to evaluate the evidence for regime shift.
The aim of this master project is to:
The student will have to:
The student should:
Additional knowledge on the Norwegian Sea ecosystem, multivariate analysis, hypothesis testing and non-linear dynamics is advantageous.
Location: The project will take place at the Institute of Marine Research in Tromsø, Norway.
IMR supervisors: Lucie Buttay and Benjamin Planque
Contact persons: Lucie Buttay (lucie.buttay@hi.no), Tel : (+47) 45390464 and Benjamin Planque (benjamin.planque@hi.no), Tel : (+47) 488 93 043
Applicants should send a CV and a letter of application by email to Lucie Buttay and Benjamin Planque
Published: 28.09.2022
