Vill du jobba med marinbiologi, marinekologi, sötvattensbiologi, sötvattensekologi, limnologi eller hållbar utveckling? Genom ditt ex-jobb hos oss gör du en insats för Östersjön, Västerhavet eller för våra sjöar och rinnande vatten.
Som examensarbetare hos oss får du arbeta med verkliga problemställningar inom pågående forskningsprojekt tillsammans med handledare som är Sveriges ledande experter inom området. Du får möjlighet att använda dina teoretiska kunskaper i praktiken och har chans delta i spännande fältjobb.
Våra examensarbeten grundar sig i ett hållbarhetsperspektiv och innefattar allt från akvatiska ekosystem, fisk, fiske och skaldjur till sälar och sjöfågel.
Fish welfare: Physiological responses to anaesthisia in brown trout
Bachelor or Master project in biology, 15-60 hp
This research project aims to explore how brown trout respond to different anaesthetics. When set in water with an anaesthetic agent, fishes initially respond with increased activity. This results in a cascade of physiological processes in the fish. In this project some of these responses will be investigated.
Background
There is a wide array of different teleost species used in scientific research world-wide. These fish are frequently anaesthetised for various procedures and previous studies suggest that there is a divergence in the response to different anaesthetics among species. The use and efficiency, from a practical point of view, of anaesthetics in different species have been studied and reviewed. However, the fish welfare aspect and the in depth understanding of the pharmacological mechanism of action and effect in different species are largely unknown. In view of our increased awareness of animal welfare, also regarding fish, along with an increased use of fish as experimental animals, standardised anaesthetic protocols that are species specific is a necessity to assure best practices with focus on fish welfare.
In earlier experiments we have shown that the stress (cortisol) response in brown trout appear to be higher in more acid water; non-buffered tricaine methanesulfonate lower the pH.
Methods
This project we will attempt to investigate thes further by comparing the response of juvenile brown trout to four treatment (non-buffered tricaine methanesulfonate, buffered tricaine methanesulfonate., river water and river water with pH=3 (using hydrochlorid acid).
Blood sample will be taken from about 80 trout and the blood will late be analyzed.
Depending on the number of credits the student wish to achieve the brains of the trout will also be sampled and analyzed for monamines (such as dopamine and noradrenaline).
Contacts
Erik Petersson
Dept. Aquatic Resouces (SLU)
erik.h.petersson@slu.se 010-4784239
Svante Winberg
Uppsala University
svante.winberg@neuro.uu.se
Dept. Anatomy, Physiology and Biochemistry (SLU)
Svante.winberg@slu.se
Fish welfare: Physiological responses to anaesthisia in zebrafish
Bachelor or Master project in biology, 15-60 hp
This research project aims to explore how zebrafish respond to different anaesthetics. When set in water with an anaesthetic agent, fishes initially respond with increased activity. This, in turn, onset a cascade of physiological processes in the fish. In this project some of these responses will be investigated.
Background
There is a wide array of different teleost species used in scientific research world-wide. These fish are frequently anaesthetised for various procedures and previous studies suggest that there is a divergence in the response to different anaesthetics among species. The use and efficiency, from a practical point of view, of anaesthetics in different species have been studied and reviewed. However, the fish welfare aspect and the in depth understanding of the pharmacological mechanism of action and effect in different species are largely unknown. In view of our increased awareness of animal welfare, also regarding fish, along with an increased use of fish as experimental animals, standardised anaesthetic protocols that are species specific is a necessity to assure best practices with focus on fish welfare.
Zebrafish is the second most common laboratory aninmal in Sweden right now and knowledge about zebrafish behavior and physiology are important for future care and housing of the species.
In earlier experiments we have gathered information about the stress response in zebrafish to metomidate and tricaine methanesulfonate. We now like to investigate the response to three other anaesthetic methods: eugenol, benzocaine and rapid cooling.
Methods
Zebrafish will be anaesthetized with the three methods mentioned above, the fish will thereafter be sampled for cortisol (whole –body). This require that the cortisol is extracted, i.e. many days in the lab
Depending on the number of credits the student wish to achieve the brains of the zebrafish will also be sampled and analyzed for monamines (such as dopamine and noradrenaline).
Contact
Erik Petersson
Dept. Aquatic Resouces (SLU)
erik.h.petersson@slu.se 010-4784239
Svante Winberg
Uppsala University
svante.winberg@neuro.uu.se Dept. Anatomy, Physiology and Biochemistry (SLU) Svante.winberg@slu.se
Are you interested in the effects of climate on sea urchins and would like to do a Masters project in South Africa?
Research Question: Does exposure to pH variability within coastal seascapes mediate the impacts of future ocean acidification on the Cape urchin (Parechinus angulosus)?
It is well established that calcifying organisms are vulnerable to the effects of low pH, particularly in their early life stages. For example the early life stages of many species of sea urchins face developmental delays and regression as a result of the physiological constraints associated with extreme low pH. Based on preliminary research, the endemic Cape urchin Parechinus angulosus appears to be similarly affected.
Coastal habitats are known for their variability in physico-chemical conditions, including pH which can vary by up to 1 pH unit in some habitats. This may be particularly apparent in vegetated habitats (macroalgae and seagrass) where pH increases during the day through photosynthesis. This exposes organisms utilising these habitats, often as nurseries and refuges, to high pH variability to which they become adapted and which can infer a degree of resilience to environmental change. For example, a recent study found that the embryos of giant purple sea urchins (Strongylocentrotus purpuratus) spawned from adults associated with giant kelp were more pH-resilient than embryos from adults outside of kelp forests.
This study will assess whether parental exposure (adult Cape urchin) to variable pH in macrophyte habitats where they naturally occur will influence the sensitivity of their larvae to low pH associated with future acidification. Adults will be collected from two contrasting coastal habitats, one where pH variability is naturally high (macrophyte beds) and another where pH conditions are more stable. The adults from each habitat will be artificially spawned to produce larvae which will be exposed to pH treatments associated with future ocean acidification in the laboratory using established experimental methods. Endpoints such as growth rates, development, survival, and metabolic rates will be compared in the larvae originating from either habitat. The study will also utilise autonomous sensors to continuously monitor pH over relevant temporal scales in these habitats to inform appropriate experimental treatment conditions.
The hypothesis for this study is that adult Cape urchins that are exposed to more variable pH conditions as adults may produce more resilient larvae. These findings will inform management of natural coastal ocean acidification refugia.
If you think this sounds like an exciting project, do not hesitate to contact charlotte.berkstrom@slu.se!
Charlotte Berkström, forskare
Institutionen för akvatiska resurser, Kustlaboratoriet, SLU
charlotte.berkstrom@slu.se, 010-478 41 65
Är du intresserad av fisk, fiskekologi och fiskefrågor, och vill göra examensarbete i Tanzania?
Vår forskargrupp söker nu en mastersstudent för projektarbete (förslagsvis 60 hp) inom ramarna för projektet ”FishLinks - Driver turisters fiskkonsumtion ett ohållbart fiske på korallrev: en socio-ekologisk studie i tropiska havslandskap”. Projektet kommer att starta vårterminen 2024, med fältresa till Tanzania under januari och framåt. Huvudfokus med projektarbetet kommer att vara hur ett turismdrivet fiske påverkar fisksammansättningen på djupa och grunda korallrev i Tanzania, förslagsvis på Zanzibar (intensiv turism) och Mafia Island (lite turism). Insamling av data kommer i första hand att utföras från båt och med videokameror (baited remote underwater video). Det finns också möjlighet att inom ramarna för det beskrivna projektet utveckla eller expandera frågeställningar och/eller metoder. Tycker du att detta låter spännande, tveka inte att kontakta:
Maria Eggertsen, forskare
Institutionen för akvatiska resurser, Kustlaboratoriet, SLU
maria.eggertsen@slu.se, 010-478 41 41
Charlotte Berkström, forskare
Institutionen för akvatiska resurser, Kustlaboratoriet, SLU
charlotte.berkstrom@slu.se, 010-478 41 65
Diana Hammar Perry, miljöanalytiker
Institutionen för akvatiska resurser, Havsfiskelaboratoriet, SLU
diana.perry@slu.se, 010-478 40 97
Population-specific distribution of sea trout in the Baltic Sea.
Independent work in biology /environmental science, 30-60 p, SLU Aqua.
How?
We are looking for a motivated MSc-student to analyze existing data from more than 50 000 tagged and recaptured sea trout in the Baltic Sea to help us answering the following questions:
Why?
Anadromous trout (sea trout) migrate from their birth river to forage and grow at sea, returning to the river to spawn. For sea trout foraging in the Baltic Sea, we have very limited knowledge about how far fish migrate from their birth river, whether sea trout from different populations display similar or dissimilar migration patterns at sea, and how consistent their migration patterns are over time. This knowledge is key for understanding how changes during the marine phase might impact sea trout populations. We hope you will help us learn more!
Location
SLU-Aqua in Ultuna, Drottningholm (Stockholm) or Öregrund
Contact us for more information:
philip.jacobson@slu.se, +4673-6141816; rebecca.whitlock@slu.se; +46104784265
How?
We have several datasets, some including more than 120 years of data, which can be used to study various aspects regarding the life-history of European eel. There will also be opportunities to assist in lab work and field activities, such as tagging, fyke-net fishing, dissections.
Why?
The European eel is classified as Critically Endangered by the IUCN red list as their recruitment have decline by 90-95%. Current management efforts aim to reverse this negative development. There are many knowledge gaps regarding the ecology and behavior of the European eel that would aid this work. We hope you will help us filling these knowledge gaps!
Location
SLU-Aqua in Ultuna, Drottningholm (Stockholm) or Öregrund
Contact us for more information:
josefin.sundin@slu.se, 010-4784224; philip.jacobson@slu.se, 073-6141816
Master project in Biology (30-60 credits)
This project aims to resolve how warming of water bodies changes the efficiency of energy transfer from primary producers to fish (i.e. food web efficiency, FWE), and how this may be modified by concurrent change in other environmental drivers. The thesis project will be part of a larger project aiming to identify strategies to maintain ecosystem services in face of multiple environmental stressors, with the goal to maintain the ability of aquatic ecosystems to act as carbon sinks and uphold high production of fish biomass in the future.
Along with warming, many freshwater and coastal ecosystems are becoming greener and browner (caused by excess humic substances and nutrients). The key factors (temperature, light, nutrients) that control basal energy production in aquatic ecosystems are thus changing. Even though the link between nutrients, light, temperature and algal growth is more or less established, the flow of energy produced by these primary producers to higher trophic levels such as fish is less predictable. The latter is especially true for the combined impact of these environmental drivers on FWE.
The student (one or several) will set up tank experiment(s) with phytoplankton, zooplankton and fish at our coastal experimental field site in Forsmark to test how warming may change FWE, as well as the potential for browning and/or greening of waters to modify those responses. The detailed set-up and more specific study questions will be decided after discussions between the student and supervisors. You will learn skills such as experimental design, sampling of plankton and fish, identification of aquatic organisms, statistics and scientific writing. Preferred project start would be sometime in the period May-July 2023.
Not only will you gain new knowledge and skills by doing your own project, but you will also become an integrate member of our research group Fish in food-webs, where you will join group meetings and seminars at campus Ultuna in Uppsala. There may also be opportunities for paid part-time work helping out in the field or lab while doing your project and to contribute to a scientific publication.
Magnus Huss, universitetslektor, studierektor
Institutionen för akvatiska resurser, Kustlaboratoriet, SLU
magnus.huss@slu.se, 010-478 41 27
The suggested topics are suitable for master student projects. The projects can include field work, lab work, literature studies, data analysis and scientific writing.
The contents and scope of the work can be discussed and adapted to prevailing conditions.
Background
The populations of seals and cormorants in Sweden have increased in size and distribution during the last decades.
Consequently, requirements and needs of information about the ecological roles of seals and cormorants have increased, e.g. for inclusion of top predators in ecological models and for development of ecosystem-based management. In addition, conflicts with fish conservation biology and coastal fisheries have intensified.
At present, relevant information on prey choice and abundance of these predators and their impact on fish stocks is insufficient.
Diet analysis of seals and cormorants
Monitoring of seals and cormorants
Predator-prey dynamics
Contact:
Karl Lundström, forskare
Institutionen för akvatiska resurser, Havsfiskelaboratoriet, SLU
karl.lundstrom@slu.se, 010-478 41 38
Masterprojekt i biologi, 30-60 hp
Brinner du för att arbeta med biologisk mångfald i havet? Då är det här projektet något för dig. Projektet bygger på två innovationsprojekt som Helsingborgs stad har arbetat med i Öresund de senaste åren. Visionen i Helsingborgs stad är att arbeta för att öka den biologiska mångfalden i kustområdena.
Tyvärr har många viktiga livsmiljöer i grunda kustområden försvunnit genom historien, i takt med att Helsingborgs stad utvidgats. De grunda områdena är nyckelområden när man talar om biologisk mångfald. De fungerar både som skafferi och barnkammare för många olika djur och växter.
Speciellt i hamnarna möter djuren raka kajkanter och ingenstans att gömma sig eller hitta mat. Det har Helsingborgs stad försökt göra något åt. I en av de största hamnarna har ett konstgjort rev byggts upp och strukturer har satts upp på kajkanten för att bidra till större komplexitet i livsmiljöerna och därmed fler hem för olika djurarter och alger.
I detta examensarbete kommer du att vara med och undersöka mer i detalj vad konstgjorda strukturer, som ett rev och strukturer på kajkanter, kan bidra med när vi pratar om biologisk mångfald i kustområden. Närmare bestämt kommer du i projektet att behöva skaffa data om artsammansättning och biomassa vid de olika strukturerna i hamnen och utföra analyser för att se vilka effekter de har. Du kan hjälpa till att forma ditt projekt i den riktning som är relevant för dig. Det finns många alternativ och oavsett vilken väg du väljer kommer du att bidra till ny kunskap om hur kustkommuner och städer kan arbeta aktivt för att öka den biologiska mångfalden i grunda kustområden med fokus på hamnar.
Arbetet utförs som ett samarbete mellan Helsingborgs stad och SLU, under handledning vid SLU av Lena Bergström, Institutionen för akvatiska resurser. En marinbiolog anställd vid Helsingborgs stad kommer att knytas till projektet och kommer att kunna bistå med expertis i ditt fältarbete och kring biologi i Öresund. Arbetet kan påbörjas från och med höstterminen 2022.
Lena Bergström, forskare
Institutionen för akvatiska resurser, Kustlaboratoriet, SLU
lena.bergstrom@slu.se, 010-478 41 16
Thesis work in biology or sustainable development at the Department of Aquatic Resources, SLU, 15-30 ECTS credits.
Within this project you will have the opportunity to develop a socio-ecological model for the Bothnian Sea that can be used for future management decisions in collaboration with stakeholders, managers and scientists.
Background: A key aim in ecosystem-based management (EBM) is to establish common goals among stakeholders, as this is expected to enable the continued delivery of ecosystem services, while reducing user conflicts. Socio-ecological models are often used to support this aim. The models help increase the understanding between stakeholders and scientists and investigate how management actions could affect the ecosystem and the people who depend upon it. The Swedish Agency for Marine and Water Management has initiated an EBM pilot project in the southern Bothnian Sea to involve stakeholders in developing an ecosystem-based management that integrates environmental goals with societal goals for the region.
Project: As part of the pilot EBM project, you will develop a socio-ecological model for the Bothnian sea in collaboration with stakeholders, managers and scientists. This, so called fuzzy cognitive model can be used in preparing future management decisions and increase the understanding between managers, stakeholders and scientists of the ecological and societal processes that affect environment status.
Practical work includes conducting interviews with managers and stakeholders and contributing to workshops within the southern Bothnian Sea EBM project. You should be familiar with R, interested in ecosystem-based management and comfortable interacting with people of different backgrounds. No previous modelling experience is necessary.
Contact:
Within this project you will have the chance to evaluate how exposure to algal toxins in fish from the Baltic Sea has changed over time, and in addition link levels of these substances to fish health data from ongoing environmental monitoring.
The eutrophication of the Baltic Sea is driving large blooms of phytoplankton and cyanobacteria as well as contribute to the occurrence of filamentous algae. The increased abundance of these primary producers can lead to an elevated production
of algal toxins with potentially harmful effects on fish. As part of current environmental monitoring is the programme integrated coastal fish health monitoring – a programme where coastal fish (e.g., perch) is examined in relation to different fish health parameters, from different reference stations along the Swedish coastline. At station Kvädöfjärden in the Baltic Proper, an assumed unaffected area but with large algae blooms during the summer, ongoing health examinations show that perch is far from unaffected. Signs of oxidative stress, immunological response and altered metabolism that cannot be coupled to anthropogenic contaminants points to algal toxins, showing similar effects in ecotoxicological studies, as a potential cause for the deteriorating fish health status in the area.
The project will take advantage of material (perch) collected within the integrated coastal fish health monitoring and stored at the Environmental Specimen Bank at the Swedish Museum of Natural History to do a retrospective study of algal toxins in perch from 1995 to 2019, as well as combine the information with already existing data for fish health. By doing so you will be able to answer how these substances change over time, are the exposure stable or is there an upward/downward trend? You will also have the opportunity to evaluate possible effects of algal toxins in the environment by coupling the chemical data to fish health parameters from the same individuals. Combined, these two research questions will advance the field of algal toxins in the Baltic Sea and contribute to the overall understanding of future needs in this area; no problem exists, annual monitoring is necessary, improved measures to reduce nutrients is warranted, other conclusions?
Practical parts of the project involves sample preparations and aiding in the chemical analysis both done at Stockholm University at the Department of Environmental Science (ACES). In addition to that, data handling and statistical analysis as well as scientific writing will be included and conducted at the Freshwater Institute at Drottningholm, Stockholm.
In this research project you will explore the behavioural effects of tagging using the European eel. Fish will be collected, held at the laboratory, tagged with PIT-tags, and behavioural experiments will be conducted. The experiments will be videorecorded and analysed using automated software.
Mark and recapture techniques are traditionally used in ecology to estimate a range of parameters, such as migration patterns, growth, survival, and population size. In fish ecology, both external and internal tags are used to answer such questions. According to the 3R principle for ethical use of animals (replace, reduce, refine), tagging methods should affect the animal to the least possible extent. The test animal might be affected by the tagging procedure and/or by the tag itself, and behave in an unnatural way, or even suffer from injury or mortality due to tag and/or handling. Such cases induce suffering to the animal, but cases of less detrimental effects can still bias the data (without harming the fish). Most tagging procedures are quite well developed and does not harm the fish, but non-lethal effects, such as behavioural effects, are important to evaluate since it can bias the data.
This research project will explore the behavioural effects of tagging using the European eel (Anguilla anguilla). It is assessed as critically endangered on the IUCN red list, wherefore data on the effects of different research techniques, such as tagging, are particularly needed.
The student’s task will consist of collecting eels (or use eels that are already available at the laboratory), tag them with PIT-tags and perform behavioural experiments. All experiments will be video recorded. Since the eel is primarily night active, behavioural trials can also be run after sunset, using IR lights and IR sensitive cameras. The specific experiments to perform depends on the student’s interest and whether it’s a 30 or 60 hp thesis. Relevant behaviours to measure include swimming activity, feeding, boldness, sheltering and similar. Swimming activity will be tracked using automated tracking software. Other behaviours will be analysed using behavioural scoring software. Data collected within the project can also be combined with existing long-term data on tagged eels.
The work will take place at the Institute of Freshwater Research, Stockholm - Drottningholm, under supervision of Dr Josefin Sundin. The student should have an interest in fish ecology, fish handling, data analysis, statistics, and scientific writing. The work can commence at any time, depending on whether fish will be collected/bought for the experiment, or if using eel that are already available at the laboratory.
Josefin Sundin, forskare
Institutionen för akvatiska resurser, Sötvattenslaboratoriet, SLU
josefin.sundin@slu.se, 010-478 42 24
In this research project you will explore migration behaviour and survival of the European eel in a natural river. When the eels start their migration back to the Sargasso Sea, they are hindered by hydropower plants. You will track tagged eels and investigate their migration behaviour and quantify hydropower induced mortality.
River ecosystems serve an important role for biodiversity, but they also provide renewable energy via hydropower electricity production. Hydropower plants, however, hinder natural river connectivity and often involve the construction of dams, causing severe ecological damage to numerous organisms. The critically endangered European eel (Anguilla anguilla) is one of many diadromous species that suffers greatly from hydropower plants. It is affected both by up- and downstream migration barriers, hydropower induced mortality, and habitat destruction and alteration. Our knowledge on the effects of hydropower on the European eel is currently insufficient to provide policymakers and stakeholders with tools to improve the conditions.
Recently, the Government Offices of Sweden decided on a national plan to retrial the environmental legal conditions for all hydropower plants. This enormous project aims to ensure that all hydropower plants in Sweden follow national and international (EU) environmental legislation, which is currently not the case for most hydropower plants. In general, detailed knowledge about the negative effects of hydropower on river connectivity and diadromous species is lacking from natural systems. This means that we are currently lacking the knowledge that will very soon be needed within the national retrial plan. This project will fill some of those knowledge gaps.
The student’s task will consist of tracking tagged eel in a river system. Depending on start date, the student can also be involved in the tagging procedure. In that case, collecting and caring for the fish will be part of the work. The migration data will be used to estimate survival (including hydropower induced mortality) and movement. Data collected within the project can also be combined with existing data on migration and survival.
The work will take place at the Institute of Freshwater Research, Stockholm - Drottningholm, and at river Kävlingeån in Skåne (southern Sweden). The work will be supervised by Dr Josefin Sundin. The student should have an interest in fish ecology, fish handling, data analysis, statistics, and scientific writing. Since some eels have already been tagged within this system, the work can commence at any time by analysing existing data. Additional tagging will be conducted in ~May and September 2022.
Josefin Sundin, forskare
Institutionen för akvatiska resurser, Sötvattenslaboratoriet, SLU
josefin.sundin@slu.se, 010-478 42 24
Den svartmunnade smörbulten är en fiskart med ursprung från Svarta havet och Kaspiska havet och har sannolikt kommit via barlastvatten till Östersjön. Den rapporterades första gången 1990 i Gdanskbukten där den nu är den vanligast förekommande kustnära fiskarten. År 2008 rapporterades arten för första gången i Sverige, i Karlskrona skärgård, och den finns nu också från Kalmarsund och upp till Gävlebukten, samt runt Gotland och i Göteborg.
Den svartmunnade smörbulten är en invasiv art med hög reproduktionstakt och hög tolerans för olika miljöfaktorer. Det finns risk för att den kan komma att konkurrera med andra bottenlevande arter och även äta rom och yngel från inhemska arter men den kan också vara en resurs för rovfisk och för människor. En uttalad risk är att arten vandrar upp i sötvatten och här behövs kunskap om dess vandringsförmåga och om vilka barriärer som kan hindra arten att ta sig upp i fiskvägar. För att nyttja arten och utveckla effektiva metoder för fiske behövs kunskap om hur arten beter sig vid olika fiskeredskap. Nedanstående projektförslag är experimentella studier som bidrar med kunskap på båda dessa viktiga områden och de är en del av forskningsprojektet Svartmunnad smörbult – förvandla risk till resurs.
Alla experiment utförs i Älvkarleby, vid Dalälven söder om Gävle, antingen vid SLU Fiskeriförsöksstation (FFS) eller vid Vattenfalls experiment anläggning Laxeleratorn. Beroende på bakgrundskunskaper och intresse kan examensarbetet göras antingen inom biologi eller miljövetenskap med utrymme för egna frågeställningar. Omfattning är flexibel och examensarbetena kan göras på kandidat- eller masternivå.
Ann-Britt Florin, avdelningschef
Institutionen för akvatiska resurser, Kustlaboratoriet, SLU
ann-britt.florin@slu.se, 010-478 41 22
Svartmunnad smörbult – förvandla risk till resurs | Externwebben (slu.se)
Foto: Isa Wallin och Anna-Li Jonsson, SLU.
In this research project you will explore the possibility to use eye-recognition software as a non-invasive tool for individual identification of fish. Fish will be collected, held at the laboratory, and photographed over time. The photographs will be analysed with iris-recognition software to evaluate the method.
Mark and recapture techniques have traditionally been used in ecology to estimate a range of parameters, such as population size, migration patterns, growth and survival. In fish ecology, both external and internal tags are used to answer such questions. According to the 3R principle for ethical use of animals (replace, reduce, refine), non-invasive methods should be used whenever possible, and the need to develop new techniques is evident.
This research project will explore the possibility to use eye-recognition software as a non-invasive tool for individual identification of fish. The specific species to work with can be decided together with the student, but we suggest working with the Northern pike (Esox lucius). Pike is a highly targeted species for recreational fishing. Currently, it is common practice to catch, photograph and release the fish alive (catch and release fishing). Within a citizen science context, a photograph-based identification technique could greatly advance our understanding of pike ecology and simultaneously benefit fish welfare. Another suggestion for study species is the European eel (Anguilla anguilla). It is assessed as critically endangered on the IUCN red list, wherefore non-invasive research techniques are particularly needed.
Depending on whether the student wishes to do a 30 or 60 hp thesis, the project can be combined with testing whether the body patterns along the side of the pike can be used for identification.
The student’s task will consist of photographing fish at fixed intervals during a determined time period. Collecting and caring for the fish will be part of this work. The photos will then be analysed using the VeriEye software (Neurotechnology). Body patterns can be analysed using ImageJ software, or AI identification (depending on the development stage of the latter software). If photos are available from elsewhere, this project can be adapted to online teaching, where all supervision will take place via zoom meetings. The student will in that case receive digital photos and analyse them from wherever the student is resident.
The work will take place at the Institute of Freshwater Research, Stockholm - Drottningholm, or online, under supervision of Dr Josefin Sundin and Dr Göran Sundblad. The student should have an interest in data analysis, statistics and scientific writing. The work can commence at any time, depending on availability of fish photographs (if the project is done online) or when the study species can be collected and photographed.
Josefin Sundin, forskare
Institutionen för akvatiska resurser, Sötvattenslaboratoriet, SLU
josefin.sundin@slu.se, 010-478 42 24
Göran Sundblad, forskare
Institutionen för akvatiska resurser, Sötvattenslaboratoriet, SLU
goran.sundblad@slu.se, 010-478 42 92
Recreational fishing is a popular activity with several human benefits. Excessive fishing can however have negative effects on fish stocks. In many areas in Sweden, fishing with handheld gears is open access, meaning that anyone can fish. The lack of registration poses challenges for estimating recreational fishing pressure, a key variable for a sustainable fisheries management. To increase our knowledge on recreational fishing in Sweden, the Department of Aquatic Resources conducts yearly surveys of recreational fishing.
This research project will use data collected during the summer of 2020 in Lake Mälaren. The field study focused on the pikeperch (Sander lucioperca) trolling fisheries, and consisted of two parts. The first part was an intercept creel survey, where local fishers were counted and intercepted during fishing for interviews regarding gear, effort and catch. The creel survey covered three larger areas sampled on a subset of days. To complement the creel survey, continuous counting of effort was conducted at selected sites using time-lapse cameras. The two surveys thus covered i) large areas – few occasions and ii) small areas – many occasions. By combining the two survey techniques, the aim is to estimate total recreational fishing effort and provide advice for optimisation of future surveys.
Depending on whether the student wishes to do a 30 or 60 hp thesis, the project can focus on either or both of the two data collection methods.
This project requires an interest in survey design and estimation statistics. Practical work will consist of digitizing the data, including counting effort from the cameras and statistical analysis. The work can be performed online or at the Institute of Freshwater Research, Drottningholm, under the supervision of Dr Göran Sundblad and Dr Nuno Prista (stationed at the Institute of Marine Research, Lysekil).
The student should have an interest in data analysis and statistics. Some knowledge of recreational fishing is advantageous but not necessary. The work can commence at any time.
Göran Sundblad, forskare
Institutionen för akvatiska resurser, Sötvattenslaboratoriet, SLU
goran.sundblad@slu.se, 010-478 42 92
The population of the European eel Anguilla anguilla (L.) is distributed from the North Cape to the Nile Delta, and in all waters in-between – in a panmictic population. That whole stock is derived from a single spawning location, in the far Sargasso Sea (Bermuda) – youngsters drift to our continent and migrate into inland waters; maturing eels leave our rivers and swim back to the Sargasso. Throughout the whole distribution area, small-scaled fisheries occur, targeting different life stages and using a wide variety of techniques. During the 20th century, the population has gradually declined to ~10% of its former abundance; since 1980, recruitment of youngsters from the ocean rapidly declined too. In 2007, the EU adopted the Eel Regulation for the protection and recovery of the stock. In this context, knowledge on the history of the stock and fishery may contribute to the effective protection, and the recovery of this remarkable fish.
Circumstantial evidence indicates that the eel stock might have been in decline since the early-1800s, mostly due to habitat loss (draining of swamps) and migration barriers (dams). In the early 1900s, technical innovation and better marketing enabled the development of commercial fisheries, primarily in mainland Europe, mostly for export to Germany (steam trains!), for smoking (Dekker 2019ai). These commercial fisheries (500 to 5000 kg per fisher per year, thousands of fishers) replaced the former subsistence/artisanal fisheries (5 to 500 kg per fisher per year, millions of fishers). Historical sources documenting the subsistence/artisanal fisheries are almost absent, while the documentation of the commercial fisheries is incomplete until ~1950 (Dekker 2019bii). The research question now is: did the replacement of subsistence/artisanal, by commercial fisheries intensify the exploitation pressure, or not? And did this exploitation contribute to the decline of the stock? This requires the comparison of undocumented decades, to little documented decades. In the absence of the regular type of information (catches, efforts, prices, …), it was noted that newspapers regularly publish short articles about the catch of a giant eel. These stories usually indicate date, location, and size of the eel (quantified information!) If exploitation pressure increased, one would expect the size of these giants to diminish, or the number of reports to go down. In Dutch, the conger (sea-eel) and the river-eel share common names, so species identity is a problem. Splitting up results by habitat-type, however, solved that. Note that not many giant river-eels were reported before 1900, and that their size diminished almost consistently over time, since 1900. This intriguing result needs confirmation from other countries; and other countries might improve our insight in the how and why. Any other country (in Western Europe) will be of value, especially since you as a native speaker will be much more able to understand historical stories than I am.
Newspaper archives are often available on-lineiii, and most archives offer a search engine. The student will explore these archives, master the data retrieval procedures, extract the data and compile a database. Though the Dutch results set a clear example, unknown problems might occur, for which creative solutions must be found. Aiming at a consistent data set, a large amount of time will go into the rigorous extraction procedures. However, in my experience, more time was lost on intriguing stories about eel distracting my attention, than on the extraction itself (e.g. a butcher’s wife, calling her eight eels to assemble for their feeding hour). Creativity and ingenuity will be required, to deal with historical complexities and unforeseen problems. Analysis of the compiled data, and reporting. Joint publication in a popular article (national), and potentially a contribution to the final scientific article (international).
Since all data are in on-line archives, this project is not time-bound, nor location specific (visits to the physical archives?). Estimated time: three - six months? Time load will depend strongly on the complexity of the archives, the national tradition and culture around eels, and your own focus. This job might fit students in history or socio-ecology as well.
Willem Dekker, forskare
Institutionen för akvatiska resurser, Sötvattenslaboratoriet, SLU
willem.dekker@slu.se, 010-478 42 48
SLU:s Fiskeriförsöksstation i Älvkarleby producerar cirka 140 000 laxar och öringar per år för Dalälven. En förutsättning för ett miljövänligt och djuretiskt vattenbruk är att det bedrivs forskning på avel och odlad fisk. Här pågår forskning och miljöanalys och här finns akvarier, bäckar och älv för experiment, och dessutom kunnig personal. Vi söker nu examensarbetare till:
Skarven har pekats ut som en potentiellt viktig predator på smolt (utvandringsmogena lax och öring ungar) men vetenskapliga uppskattningar av skarvens inverkan idag i Dalälven saknas. Eftersom en del av den lax och öring smolt som sätts ut i Dalälven märks med Pit‐tag finns det en möjlighet att leta efter dessa märken i områden där skarvarna haft sina kolnoier. Projektet innebär främst scanning av pit‐tag märken i skarvkolonier längs kusten men även genomgång av spybollar från skarv och andra fåglar kan inkluderas. Fältinsamling utförs under hösten efter häckningen, dvs någon gång under sep‐nov 2020 eller senare.
Det är eftersträvansvärt att den fisk som sätts ut så mycket som möjligt liknar den vilda fisken. Ett problem vid många kompensationsodlingar av laxfisk att smolten som sätts ut har skador på sina fenor och även att de växer för snabbt och är för feta jämfört med den vilda fisken. I detta projekt undersöks foderregimens inverkan på kondition, överlevnad och fenskador hos odlad fisk. Även undersökningar av olika tätheter av fisk kan inkluderas. Projektet kan utföras i stort sett när som helst mellan Mars‐December.
Vid Fiskeriförsöksstationen har avelsarbete på lax och öring utförts
under nära 100 år. Under denna tid har data på den fisk som vandrar in från havet samlats in vilket möjliggör analyser av förändringar hos lax & öring i Dalälven över tid i t.ex. storlek, kondition, äggstorlek mm. Arbetet kan antingen vara helt teoretiskt och göras när som helst på året, eller involvera provtagning av fisken under antingen avelsfisket (aug) eller romtagningen (okt).
Beroende på bakgrundskunskaper och intresse kan examensarbetet göras antingen inom ekologi eller miljöanalys med utrymme för egna frågeställningar. Omfattning är flexibel och examensarbetena kan göras på kandidat‐ och masternivå.
Ann-Britt Florin, avdelningschef
Institutionen för akvatiska resurser, Kustlaboratoriet, SLU
ann-britt.florin@slu.se, 010-478 41 22
The paradigm shift from single species to ecosystem based fisheries management (EBFM) requires a broader, mechanistic and more in-depth understanding of marine ecosystems. Multispecies models able to account for trophic interactions and the effect of environmental variability on populations are an essential tool to move towards an EBFM. To account for predator-prey interactions in age-size structured population dynamic models high quality information on predator consumption, prey preference and trophodynamics are essential. Stomach data provide fundamental information on predators’ diet, but their collection has been generally limited which is considered one of the limiting factors for the implementation of multispecies models for the purposes of fisheries advice within the context of EBFM.
The Baltic Sea has been one of the fortunate exceptions. Here, stomachs of cod, the main predatory fish in the system, have been collected for decades. This dataset is important not only for the implementation of advanced multispecies models for EBFM in the Baltic, but also because it can serve as a benchmark to design future stomach sampling programs for the Baltic and other ecosystems.
This master project aims to explore the spatial and temporal correlation among the cod stomachs and the implications of sampling design and sample size for the estimation of the main processes linked to the implementation of multispecies models. The analyses are expected to yield alternative strategies of stomach sampling in Baltic cod and highlight costeffective sampling schemes which sampling intensity appropriately quantifies cod predation on clupeids in the Baltic and beyond.
Requirements: good skills in spoken and written English, basic statistical skills and familiarity with R programming (ability to write simple own functions).
Work location: Lysekil
Valerio Bartolino, forskare
Institutionen för akvatiska resurser, Havsfiskelaboratoriet, SLU
valerio.bartolino@slu.se, 010-478 40 58
Stock assessment of herring in the southern Baltic is currently based on a rigid geographical definition of stock boundaries which allocate herring western of Bornholm Island to the so called Western Baltic Spring spawning herring stock and herring on the eastern side of Bornholm to the large central Baltic herring stock. In reality, in this region herring reproduce in coastal habitats along the southern Swedish coasts and along the entire southern Baltic coast from the western to the eastern limits of the basin giving origin to a number of subcomponents within these two stocks.
The relationships among the different sub-components within and between the two stocks are poorly understood, as well as the level of mixing and geographical extents of overlap between the different components belonging to the two stocks remain unknown. This lack of knowledge on population structure has profound implications for the management of herring in the Baltic, both in terms of diversity and productivity.
This master project aims to evaluate the relationships between some of the main herring spawning components in the southern Baltic Sea to contribute to the harmonization of stock assessment units definitions and population structure. Moreover, the analyses are expected to identify solid baselines for future discrimination of the main herring components occurring in mixed catches of commercial fisheries and scientific survey across this broad geographical region.
Requirements: good skills in spoken and written English, basic statistical skills (familiarity with multivariate analyses is an advantage).
Work location: Lysekil.
Valerio Bartolino, forskare
Institutionen för akvatiska resurser, Havsfiskelaboratoriet, SLU
valerio.bartolino@slu.se, 010-478 40 58
Carina Jernberg, enhetschef
Institutionen för akvatiska resurser, Havsfiskelaboratoriet, SLU
carina.jernberg@slu.se, 010-478 40 25, 076-126 80 16
Sillgrisslor är marina, fiskätande topp-predatorer som finns runt hela norra halvklotet. De kan vara viktiga indikatorer på förändringar i ekosystem som exempelvis utsläpp av miljögifter och förändringar i fiskebestånd. Långtidsstudier har visat att man genom att följa sillgrisslorna på deras häckningsplatser kan lära sig mycket om hur ekosystem fungerar och upptäcka förändringar i näringsväven.
På Stora Karlsö utanför Gotland finns Östersjöns största sillgrisslekoloni, ca 15 000 par. Här pågår sedan 1997 ett övervakningsprogram för sillgrisslor, där bland annat överlevnad, reproduktion och födoval studeras.
Att kunna få tag i energirik föda är en förutsättning för att kunna överleva och föda upp en livkraftig unge. Flera studier har visat att sillgrisslans huvudföda är skarpsill (Sprattus sprattus). Nya data visar dock att strömming (Clupea harengus) kan utgöra en ganska stor del av dieten. Hur energiinnehållet ser ut i strömmingar av olika storlekar och hur det förhåller sig till energiinnehållet i skarpsill är idag okänt. Kunskapen är viktig för att utvärdera sillgrisslans bevarandestatus i Östersjön och hur mycket fisk som behöver sparas i havet för att säkerställa dess överlevnad.
Exjobbet handlar om att analysera energiinnehållet i ett antal skarpsillar och strömmingar som samlats in av Havsfiskelaboratoriet i Lysekil. Dessa kommer sedan att analyseras av studenten med hjälp av en bombkalorimeter, vilket är en maskin som kan mäta energiinnehåll. Detta arbete kommer att ske vid SLU i Ultuna. Data från försöken kommer sedan analyseras statistiskt. Projektet är tänkt för kandidatnivå (15 hp) men möjligheter finns också till ett mer omfattande projekt på mastersnivå, exempelvis innefattande fältarbete på Stora Karlsö där sillgrisslornas matningar av ungarna med fisk kan studeras i detalj.
www.balticseabird.com
www.storakarlso.se
Jonas Hentati Sundberg, universitetslektor
Institutionen för akvatiska resurser, SLU
jonas.sundberg@slu.se, 073-938 79 69
Fler lediga examensarbeten för dig som är intresserad av fisk och akvatisk ekologi hittar du hos våra kollegor på Vilt, fisk och miljö
Här kan du få information och inspiration från tidigare självständiga arbeten vid SLU Aqua.
Andreas Bryhn, forskare, studierektor
Institutionen för akvatiska resurser, SLU
andreas.bryhn@slu.se, 010-478 41 52