Examensarbete

Sjöfågel i spotlight: att förvandla turistfotografier till värdefulla data om sjöfågel

Kandidatarbete (15 ECTS) 

Att uppskatta populationsstorleken och undersöka den långsiktiga trenden för sjöfåglar är viktigt för bevarande och förvaltning, men det är svårt att göra korrekta uppskattningar. Nuvarande beräkningsmetoder bygger främst på båt- och flygundersökningar (t.ex. med drönare) eller teknik för fångst och återfångst (t.ex. ringmärkning av fåglar). Förutom att sådana undersökningar är tidskrävande och riskerar att störa fåglar, är noggrannheten och repeterbarheten i sådana undersökningar låg.

Det aktuella projektet är ett medborgarforskningsprojekt som syftar till att övervaka sjöfågelpopulationer (t.ex. sillgrisslor, tordmular) som lever på Stora Karlsö (det näst äldsta naturreservatet i världen) med hjälp av besökarnas bidrag. Detta projekt bygger på standardiserade fotografier tagna av besökare med sin smartphone på den mest besökta platsen på ön.

Med hjälp av en avancerad beräkningsprocess (AI Object detection) kommer standardiserade fotografier att omvandlas till populationsdata som kommer att användas för att förstå sjöfåglars dagliga rörelser och för att bedöma deras populationsstorlek. Denna studie kommer att möjliggöra långsiktiga och mer korrekta bedömningar av sjöfågelpopulationer och att bidra till att övervaka förändringar som kan påverka sjöfågelarter i Östersjön. Projektet kommer att innehålla bildkommentarer, modellträning och dataanalys.

Arbetet kommer att äga rum i Ultuna, Uppsala, och kommer att handledas av Quentin Queiros (quentin.queiros@slu.se) och Jonas Hentati-Sundberg (jonas.hentati-sundberg@slu.se).

Effekter av strandbete på akvatiska ekosystem: Fältstudier i Stockholms skärgård

Bachelor project (15 ECTS) 

Detta forskningsprojekt erbjuder en fantastisk möjlighet att utforska hur strandbete av boskap påverkar vattenvegetation, fisksamhällen och övrig biologisk mångfald. Fältarbetet sker under vår och sensommar i Stockholms skärgård och omfattar bland annat insamling av vattenprover och intervjuer med lokala bönder. Ett projekt för dig som vill kombinera praktiskt arbete med spännande forskning i en vacker miljö.

Bakgrund

Betande boskap spelar en central roll för att upprätthålla biologisk mångfald i kulturlandskap. Medan stor vikt har lagts vid betets roll inom terrestrisk naturvård har dess påverkan på akvatiska system fått relativt lite uppmärksamhet. Projektet STROBIO syftar till att fylla denna kunskapslucka genom att undersöka effekterna av bete i akvatiska habitat och utveckla riktlinjer för bästa praxis. Detta innefattar att integrera perspektiv från naturvård, fiskevård och landskapsvård.

Forskningsfrågor

• Vilka mekanismer styr effekten av strandbete på vattenvegetation och fisksamhällen?
  Hur bör strandbete utföras för att optimera effekten på biologisk mångfald, till exempel med avseende på betesintensitet och tidsperiod för betning?

Metoder

Projektet kommer att genomföras med fältstudier och laboratorieanalyser under vår och sensommar i Stockholms skärgård. Specifika aktiviteter inkluderar:

• Insamling av vattenprover för analys av eDNA, vilket används för att identifiera vilka arter som finns i de olika miljöerna.
• Provtagning av vattenprover för analys av algtoxiner, vilka studenten har möjlighet att analysera som en del av projektet.
• Intervjuer med lokala bönder för att få insikter om deras erfarenheter och metoder för strandbete.
• Kamerabaserad inventering av betande djurs beteende i strandzonen.

Beroende på projektets inrktning kan studenter även utföra analyser av vattenkvalitetsparametrar och utforska toxinnivåer eller näringsämnesomsättning i betade och obetade system. Fältarbetet erbjuder en kombination av forskning, samverkan och naturupplevelser i en av Sveriges mest vackra och biologiskt rika miljöer.

Möjligheter för studenter

Projektet erbjuder en möjlighet att kombinera fältarbete i en härlig skärgårdsmiljö med laboratoriearbete och intervjumetodik. Du kommer att utveckla värdefulla färdigheter inom provtagning, analys och kommunikation. Resultaten från projektet kan bidra till hållbara betesmetoder och bevarandet av biologisk mångfald.

Kontakt

Elin Dahlgren, forskare, elin.dahlgren@slu.se
Alfred Sandström, forskare, alfred.sandstrom@slu.se, 0761268129

Bachelor project (15 ECTS) or Master project (30/60 ECTS) in biology

Fish welfare: Physiological responses to anaesthisia in brown trout

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
Department of Aquatic Resources (SLU Aqua)
erik.h.petersson@slu.se 010-478 42 39

Svante Winberg
Uppsala University
svante.winberg@neuro.uu.se
Swedish University of Agricultural Sciences, Department of Anatomy, Physiology and Biochemistry
Svante.winberg@slu.se

Bachelor level (15 ECTS) or Master level (30/60 ECTS) in biology 

Fish welfare: Physiological responses to anaesthesia in zebrafish

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. you will spend many days in the laboratory.

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
Department of Aquatic Resources (SLU Aqua)
erik.h.petersson@slu.se 010-478 42 39.

Svante Winberg
Uppsala University
svante.winberg@neuro.uu.se
Swedish University of Agricultural Sciences, Department of Anatomy, Physiology and Biochemistry
Svante.winberg@slu.se

Seals and cormorants - Top predators in Swedish waters

Suggestions of degree projects

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

• Diet variability
• Methodology (DNA, image analysis)

Monitoring of seals and cormorants

• Photo-ID
• Camera surveillance
• Regional monitoring, e.g. in marine protected areas
• Abundance estimates

Predator-prey dynamics

• Prey selectivity
• Correlations between diet data and fish monitoring data

Contact:

Developing a socio-ecological model for risk assessment in the Baltic Sea

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

Kandidatnivå (15 hp) eller mastersnivå (30/60 hp)

Svartmunnad smörbult – förvandla risk till resurs

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.

1. Vandringsförmåga (15-60 hp), praktiska arbetet utförs under 3-6 veckors tid i augusti/september i Laxeleratorn med eventuell komplettering vid FFS i oktober för 60 hp mastersarbete. I det här experimentet studeras hur svartmunnad smörbult och två andra arter, öring och stensimpa, klarar av att vandra i en konstgjord fiskväg vid olika vattenhastigheter och med olika barriärer. Examensarbetet kan göras på en eller flera arter beroende på omfattning. Arbetet går även att göra under senare del av året på filmat material.
2. Beteende vid fiskeredskap (15-60 hp), det praktiska arbetet utförs under 2-3 veckors tid i september i Laxeleratorn. I det här experimentet studeras hur svartmunnad smörbult beter sig vid olika utformning av fiskeredskap i syftet att designa effektiva metoder att fånga arten Arbetet går även att göra under senare del av året på filmat material.

Kontakt

Kandidat- eller masternivå (15‐30 hp)

Examensarbeten om laxfisk i Dalälven

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 följande projekt:

1. Överlevnad hos lax och öringsmolt

Skarven har pekats ut som en potentiellt viktig predator på smolt (utvandringsmogen lax- och öringungar) men vetenskapliga uppskattningar av skarvens inverkan idag i Dalälven saknas. Eftersom en del av den lax- och öringsmolt som sätts ut i Dalälven märks med Pit‐tag finns det en möjlighet att leta efter dessa märken i områden där skarvarna haft sina kolonier. Projektet innebär främst skanning av Pit‐tag märken i skarvkolonier längs kusten men en genomgång av spybollar från skarv och andra fåglar kan också inkluderas. Fältinsamling utförs under hösten efter häckningen, dvs någon gång under september‐november.

2. Förbättrad kvalitet hos utsatt fisk

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 och december.

3. Historiska trender hos lekande fisk i Dalälven

Vid SLU:s fiskeriförsöksstation 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 och öring i Dalälven över tid i till exempel storlek, kondition och äggstorlek. Arbetet kan antingen vara helt teoretiskt och göras när som helst på året, eller involvera provtagning av fisken under antingen avelsfisket (i augusti) eller romtagningen (oktober).

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.

Kontakt

Bachelor projects in biology (15 ECTS)

Ecology and management of the European eel, several projects available!

Background

The European eel, Anguilla anguilla, is red listed as critically endangered due to a steep population decline. Current management efforts aim to reverse this negative development. There are many knowledge gaps regarding everything from ecology, behaviour, and physiology to development of stock assessment parameters. You can help us fill these knowledge gaps!

We have a great variety of bachelor degree projects and research training/internship related to evaluating and synthesizing information about ecology, management and data collection of the European eel. There are also opportunities to assist in lab work and field activities, such as tagging, fyke-net fishing, dissections, and more (although keep in mind that this can
be difficult to fit within a 15 hp project!).

Project examples

• Evaluating tagging and tracking data of eels in river systems, lakes and in the sea. Students can be involved in the tagging and tracking procedures, depending on time availability. Topics that can be addressed include survival (fisheries induced survival, hydropower induced mortality), movement, long distance migration, etc.
• Improve data collection programs. To monitor the eel stock, data is collected on a number of variables, such as landings, individual length, parasite prevalence, age, etc. Since data collection is time consuming and costly it is important that it is efficient. Any improvements that can be made to the monitoring programs are highly valuable, including 3R aspects.
• Evaluation of management activities such as restocking and fisheries regulations.
• Behavioural and physiological studies.

The work will be supervised by Dr Josefin Sundin and Dr Philip Jacobson. Depending on the project, the student should have an interest in fish ecology, behavioural ecology, fisheries science, data analysis, statistics, and scientific writing.

Location

At the Swedish University of Agricultural Sciences (SLU Aqua) in Drottningholm (Stockholm), Uppsala-Ultuna, or Öregrund. Several projects can also be done online.

Svenska Båtunionen söker nu en student som vill skriva sin kandidatuppsats inom ramen för vårt projekt Allemansrätten under ytan. Du kommer också ha en handledare från SLU.

Om projektet

Allemansrätten under ytan syftar till att öka kunskapen om hur det vattenburna friluftslivet påverkar den akvatiska miljön och att skapa en högre förståelse för de rättigheter och skyldigheter som gäller vid och under vattenytan. Vi vill besvara frågor som: Hur mycket blåstång eller grönslick kan plockas utan att skada ekosystemet? Finns det vattenlevande växter som inte bör röras? Och vilka regler bör gälla för olika vattenaktiviteter? Avsikten är att projektet ska spegla allemansrätten på land.

Ditt uppdrag

Studenten kommer att fokusera på faktainsamlingen i projektets första fas. Det innebär bland annat att:

• Genomföra litteraturstudier av vetenskapliga artiklar och tidskrifter för att identifiera vilken typ av flora och fauna som bör omfattas samt om det finns några geografiska skillnader som behöver beaktas.
• Sammanställa ett underlag med rättigheter och skyldigheter kopplade till vattennära och vattenburna aktiviteter.
• Intervjua sakkunniga inom relevanta områden.

Vad vi erbjuder

• En möjlighet att bidra till ett viktigt miljö- och friluftsprojekt med nationell räckvidd.
• Tillgång till experter och nätverk inom bland annat båtliv, friluftsliv och sjörätt.
• Möjlighet att publicera uppsatsen och bidra till informations- och undervisningsmaterial för Svenska Båtunionens medlemmar och allmänheten.
• Stöd och handledning från vår organisation och våra samarbetspartners.

Vi söker dig som

• Studerar på kandidatnivå inom relevanta ämnen såsom miljövetenskap eller marinbiologi.
• Har ett intresse för friluftsliv och miljöfrågor.
• Är strukturerad, analytisk och har god förmåga att sammanställa och kommunicera information.

Ansökan

Skicka in en kort presentation om dig själv, ditt studieområde och varför du är intresserad av att skriva din kandidatuppsats inom detta projekt. Bifoga även eventuella relevanta erfarenheter och referenser.

Mejla din ansökan och eventuella frågor till Slavica Lukic Stojanovic, projektledaren på Svenska Båtunionen på slavica@batunionen.se

Kontakta orjan.ostman@slu.se för att diskutera lämplig handledare på SLU.

Välkommen att bidra till ett viktigt projekt och göra skillnad för framtidens vattenburna friluftsliv!

Svenska Båtunionen är en paraplyorganisation som representerar drygt 900 båtklubbar och 180 000 enskilda båtklubbsmedlemmar. Organisationen har lång erfarenhet av båtlivsfrågor och verkar både för en bättre miljö och en utökad möjlighet till ett vattenburet friluftsliv. Vi arbetar aktivt för att minska påverkan från fritidsbåtar i våra vatten och natur, bland annat genom utbildningar, informationsspridning och påverkansarbete.

Population expansion and development of round goby in the Baltic Sea

Background

One of the most distinctive alien species invading the Baltic Sea during the last decades is the fish round goby (Neogobius melanostomus). The species originates from the Ponto-Caspian region and was first observed in the Baltic Sea in 1990 in the Polish coastal waters of the Gulf of Gdansk. The main vector mediating the establishment of the species in the Baltic Sea is ballast water from ships. The round goby has since the first observation become established in all basins in the Baltic Sea, with the northernmost finding of the species along the Finnish coast of the Bothnian Bay. Following establishment, the abundance of round goby has sky-rocketed in most coastal areas, in turn potentially impacting the local coastal ecosystem structure and functioning. As many coastal fish species targeted by small-scale fisheries in the Baltic Sea have declined, the species has today become an important target in coastal fisheries in some areas. Despite the generally good knowledge on the spatial extent of the establishment of round goby in the Baltic Sea, relatively little is known about the population development in different coastal areas of the sea. Such information is key to understanding the general biology of species, what factors regulate its population development, and whether measures should be taken to manage and mitigate the ecosystem effects following the invasion of round goby.

Aims

• To compile Baltic wide data on round goby population expansion and development and analyze time-trends in the abundance of the species in different parts of the
  Baltic Sea coast,
• To understand potential factors driving population expansion and development of the species by addressing commonalities and differences in time-trends across areas.

Description

In this project you will collate data from coastal fish monitoring programs in all countries bordering the Baltic Sea with a focus on round goby abundance. We already have a well established network with responsible persons for the monitoring programs, and data should be rather easily accessible. The analyses suggested include time-trends of round goby abundance across different coastal areas of the Baltic Sea, addressing common patterns in the temporal development of the species across areas, and evaluation of the trends over time in light of the local environmental conditions and the structure and temporal development of the resident coastal fish community as a whole.

Contact

Jens Olsson, Researcher at the Department of Aquatic Resources, Ultuna in Uppsala, jens.olsson@slu.se; 076-1890538

Matilda Andersson, Environmental Assessment Specialist at the Department of Aquatic Sciences and Assessment, Ultuna in Uppsala, matilda.l.andersson@slu.se

Master project in Biology (30-60 credits)

This thesis project aims to resolve how marine heatwaves affect coastal food webs, including species interactions and biomass production from plankton to fish. The thesis will be part of a larger project aiming to improve our knowledge about risks posed by climate change-driven extreme marine weather events on marine food webs and fisheries as a step towards developing effective adaptation strategies.

Background

Waters around the globe are not only exhibiting an increase in mean temperatures, but marine heatwaves – periods of unusually high water temperatures – are also increasing in frequency, including in the Baltic Sea. Marine heatwaves and other extreme marine weather events can alter the biodiversity, functioning and productivity of food webs, with potential implications for fisheries and marine food production. Whereas we have learned a lot about how food web responses to warming depend on interactions within and among species, this is largely unknown for heatwaves.

Methods and learning opportunities

The students (one or several) will join in setting up a tank experiment to test how simulated heatwaves impact juvenile fish production, biomass distributions (between phytoplankton, zooplankton and fish) and the duration and mechanisms of those responses. You will carry out the experiment using our coastal mesocosm facility for temperature-experiments. The detailed set-up and more specific study questions will be decided after discussions between the student and supervisors. During the project you will not only learn about food web responses to heatwaves but also skills such as experimental design, sampling of plankton and fish, identification of aquatic organisms, statistics and scientific writing. Preferred project start would be late April 2025.

In addition to gaining new knowledge and skills by doing your own project, you will get the opportunity to become an integrate member of our research group FishinFoodwebs, where you will join group meetings and seminars at campus Ultuna in Uppsala. There may also be opportunities to contribute to a scientific publication.

Contact

Magnus Huss, Associate Professor, Department of Aquatic Resources, SLU
magnus.huss@slu.se, 010-478 41 27

Anna Gårdmark, Professor, Department of Aquatic Resources, SLU
anna.gardmark @slu.se, 010-478 41 25

Lake experiment to determine how forest fertilizers and carbon leakage affect plankton communities

Many freshwaters in Sweden have become greener and browner over the last century due to human activities. This is linked to changes in land use which have led to increased concentrations of nutrients and dissolved organic matter (DOM) of terrestrial origin. During the same period, we have experienced a major shift in forestry practices, such that today the vast majority of forest areas in Sweden are managed by clearcutting and there has also been a concurrent shift towards dominance of coniferous forests. This has affected the amount and quality of elements transported from forests to water bodies.

This thesis project will make a significant contribution to ongoing research aiming to resolve how land use change and forestry practices affect lake ecosystem diversity and function via loading of DOM and nutrients. Futhermore, the thesis will also investigate if and how the impact depends on lake type, as lakes vary in light climate, carbon and nutrient availability.

The student(s) will specifically try to answer the questions (1) How do different combinations of forest fertilizers and DOM affect plankton production, community biomass and composition? (2) If and how does the response vary with lake chemistry?

Experimental setup

The student(s) will together with supervisors set up enclosure experiments in 6 or more lakes. We will select lake pairs consisting of one brown and one clear lake in each of three distinct geographical areas close to Uppsala, Umeå and in mid Sweden. In each lake, a set-up with small enclosures will be inoculated with lake water and local phytoplankton and zooplankton communities.

The treatments will be additions of dissolved organic matter (DOM) and nutrients. The experiment will run for approximately two weeks per lake-pair, whereafter phytoplankton and zooplankton biomass and composition will be measured. The student(s) will, with support from supervisors, set up experiments, take biological samples, analyze the results and relate them to potential effects of forestry practices on lake ecosystems.

Timing and supervision

The fieldwork will be performed during summer 2025. 1-2 student projects are available, preferably to be carried out parallel to each other (30 or 60 ects).

Contact

The supervisors are Magnus Huss (Department of Aquatic Resources (SLU Aqua), Uppsala, magnus.huss@slu.se, 010-4784127) and Karin Nilsson (VFM, SLU Umeå, karin.a.nilsson@slu.se, 070-2055017), and the student can be associated with either SLU Aqua or SLU in Umeå and will become integrated members of their respective research groups, join group meetings and seminars. There may also be opportunities to contribute to a scientific publication.

Threatened by climate change and fisheries, seabird populations worldwide have declined since the mid-20th century. Seabirds are central-place foragers, commuting between colonies and feeding areas during the breeding season. Understanding their foraging areas is crucial for informing spatial management measures to protect habitats and prey populations. However, only 3% of the ocean is currently fully or highly protected, and establishing marine protected areas (MPAs) or implementing restriction measures without careful planning could have limited or even negative effects.

Identifying interactions between seabirds and fisheries is essential for the efficient future implementation of MPAs and for global conservation efforts. At the same time, global fishing activities, from small-scale fishing boats to industrial fishing vessels, have been tracked daily since 2012.

Using allometric relationships and extrapolating the foraging ranges of species from 23,000 seabird colonies, this thesis aims to evaluate (1) the interactions between seabirds and fisheries and (2) the potential value of current and future MPAs, as well as proposed Important Bird and Biodiversity Areas (IBAs), in protecting seabirds from fisheries. This study will help quantify threats to seabirds, assess the efficiency of MPAs, and identify areas lacking adequate protection measures.

The thesis will include spatial analyses of seabird at-sea distributions, fishing activities, and protected areas. The data will be analyzed statistically. This project is planned for a Master’s level (30–60 ECTS) and would result in the submission of a scientific paper to a high-ranking journal. The work will take place in Ultuna, Uppsala, and will be co-supervised by Quentin Queiros (quentin.queiros@slu.se) and Jonas Hentati-Sundberg (jonas.hentati-sundberg@slu.se)

Master project in Biology (30-60 credits)

We have a challenging and exciting master project on the effects of heatwaves on the Baltic herring ecosystem. In this project, you will use dynamic modelling to explore how various aspects of heatwaves affect the dynamics and fisheries of Baltic herring, their food sources, competitors and predators.

Background

Heatwaves are becoming more frequent and extreme due to climate change, especially in smaller aquatic regions such as the Baltic Sea. Fluctuations in temperature affect the primary productivity of an aquatic ecosystem as well as the behaviour and physiology of individual fish. These effects cascade through the ecosystem thought interactions such as consumption, competition and predation. It is therefore unknown how the increasing frequency and intensity of heatwaves will affect the dynamics of aquatic ecosystems. Dynamic modelling provides a tool to explore how various heatwave scenarios would affect the dynamics of an ecosystem.

Methods and learning opportunities

In this project you will work with a size-structured population model for Baltic herring. Currently, the model describes the dynamics and size structure of Baltic herring, as well as their dynamic resources consisting of two zooplankton communities and a benthos community. In the model several processes such as the growth in size, consumption and respiration of herring and the production of the resource communities are temperature dependent. Depending on your interest and the duration of the project, you will include a predator population of cod or a competitor population of stickleback or sprat in the model. You will explore the dynamics of the extended model and the effects of heatwaves on this dynamics through mathematical simulations.

For this project, we are looking for a master student with an interest in both ecosystem dynamics as well as mathematical modelling. During this project you will learn how to formulate, extend, analyse and interpret mathematical models in a biological context with a focus on size-structured population models. In addition to you gaining new knowledge and skills by doing your own project, you will get the opportunity to become an integrate member of our research group FishinFoodwebs, where you will join group meetings and seminars at campus Ultuna in Uppsala.

Contact

Jasper Croll, Postdoctoral fellow, Department of Aquatic Resources, SLU
jasper.croll@slu.se, 010-478 81 84

Anna Gårdmark, Professor, Department of Aquatic Resources, SLU
anna.gardmark @slu.se, 010-478 41 25 

Master’s Project (30/60 credits) in Biology

This research project provides a fantastic opportunity to explore how shoreline grazing by livestock affects aquatic vegetation, fish communities, and overall biodiversity. Fieldwork will take place during the spring and late summer in the Stockholm Archipelago and will include collecting water samples and conducting interviews with local farmers. It is an ideal project for students looking to combine practical work with exciting research in a beautiful environment.

Background

Grazing livestock plays a central role in maintaining biodiversity in cultural landscapes. While the role of grazing in terrestrial conservation has received significant attention, its impact on aquatic systems has been relatively understudied. The STROBIO project aims to fill this knowledge gap by investigating the effects of grazing in aquatic habitats and developing guidelines for best practices. This involves integrating perspectives from conservation biology, fisheries management, and landscape ecology.

Research Questions

• What mechanisms drive the effects of shoreline grazing on aquatic vegetation and fish communities?
• How should shoreline grazing be conducted to optimize biodiversity outcomes, such as in terms of grazing intensity and timing?

Methods

The project will be carried out through field studies and laboratory analyses during the spring and late summer in the Stockholm Archipelago. Specific activities include:

• Collecting water samples for eDNA analysis to identify species present in different environments.
• Sampling water for algal toxin analysis, which the student will have the opportunity to analyze as part of the project.
• Conducting interviews with local farmers to gain insights into their experiences and grazing methods.
• Camera-based monitoring of grazing animals' behavior in shoreline zones.

Depending on the project scope (30 or 60 credits), students may also analyze water quality parameters and explore toxin levels or nutrient cycling in grazed versus ungrazed systems. The fieldwork offers a combination of research, collaboration, and natural exploration in one of Sweden’s most beautiful and biologically rich environments.

Opportunities for Students

This project offers a chance to combine fieldwork in a stunning archipelago setting with laboratory work and interview methodology. You will develop valuable skills in sampling, analysis, and communication. The project’s findings could contribute to sustainable grazing practices and the conservation of biodiversity.

Contact

Alfred Sandström, Researcher, alfred.sandstrom@slu.se, +46 761 268 129

Elin Dahlgren, Researcher, elin.dahlgren@slu.se

Large-scale mesocosm experiment — how mysids and sticklebacks interact with pike larvae

Background

Many coastal fish communities in the Baltic Sea have experienced a regime shift where predatory fish (pike and perch) have been replaced by three-spined sticklebacks. Hypotheses for the decline in top predators involve: top-down control of adult fish by cormorants and seals, and predation on the larvae by three-spined stickleback and stickleback competition for zooplankton. However, these hypotheses are largely based on correlative field observations at rather large spatiotemporal scales, making causal inference difficult. To avoid poor management decisions and instead strive for accomplishing the best possible effect of management interventions, there is a need to understand the causal mechanisms behind observed shifts.

In the MYSTIC-project we propose that there may be other mechanisms driving the loss of predatory fish that previously have been overlooked. Invertebrate predators such as mysid shrimps have the capacity to outcompete top predators at the larval stage when they are the most vulnerable.

During spring 2025 we plan a large-scale mesocosm experiment where we want to test how mysids and sticklebacks interact with pike larvae during the early developmental phase.

Project description

• The work will be conducted at the Askö Laboratory, a field station in the outer Stockholm Archipelago, in collaboration with researchers active in the MYSTIC-project.

• We will hatch pike from fertilized roe and expose them to different combinations of mysids and sticklebacks to study pike larvae survival and whether survival is dependent on direct predation or indirectly by competition for zooplankton.

• The experimental part of the study is planned to weeks 17-21 but may be adjusted to run earlier or later depending on the temperature of the nearby spawning habitats for pike which must reach 6-8 °C in order to follow the natural progression of spawning and development.

Location

Accomodation at the field station is covered by the project. For details about your stay at Askö, please vistit the Stockholm University website.

Contact

Differences in the sex ratio across perch populations in coastal areas of the Baltic – where and why does it differ?

Background

European perch (Perca fluviatilis) is a key species impacting the food-web structure and functioning in coastal ecosystems of the Baltic Sea. Perch is also of importance for small-scaled commercial and recreational fisheries in the Baltic Sea. Recent studies have shown substantial differences across coastal areas in the status and temporal development of perch populations along the Swedish coast. Given that perch exhibit a local population structure and there are a wide range of potential pressures impacting the populations (including fishing, eutrophication, climate change, habitat availability, hazardous substances and natural predation), it is challenging to understand which factors that drives the temporal development and status of the species in different coastal areas. Such information is key for implementing the adequate measure to support and restore populations in decline.

One factor potentially influencing the status of Baltic Sea perch populations is the sex ratio of the population. Preliminary analyses suggest substantial differences in the sex ratio across populations, but little is known how it impacts the population development and what factors that influence the sex ratio of the population.

Aims

• To analyse differences in the sex ratio of perch populations across coastal areas and over time along the Swedish Baltic Sea coast.
• To understand the drivers of differences in sex ratios across areas and within areas over time.

Description

In this project you will make use of the extensive data on perch population characteristics along the Swedish Baltic Sea coast that is collected yearly within national and regional environmental monitoring programs. The data covers more than 15 coastal areas and do in some areas date back to the 1970’s. It includes data on population characteristics as relative abundance, size structure, age, individual condition and population sex ratio.

Suggested analyses within the project are to assess differences in the sex ratio across populations/coastal areas, variation in sex ratios within populations/coastal areas over time, and correlations between sex ratios and potential impacting factors including biological parameters (growth rates, size structure and condition) and abiotic variables (temperature, eutrophication, hazardous substances and fishing).

Contact

Jens Olsson, researcher at the Swedish University of Agricultural Sciences, in the Department of Aquatic Resources at Ultuna in Uppsala
jens.olsson@slu.se; +46 761-89 05 38

Swim like nobody’s watching – a comparison of fish survey methods on the Swedish West Coast

Are you interested in studying ecology, fish, and the marine environment and want to do your Masters project focused on the Swedish west coast?

Background

How do sustainable fish stocks contribute to maintaining a healthy coastal environment? Removal of large predatory fish can cause ecosystem wide alterations resulting in trophic cascades. Previous research in both the Baltic Sea and the Swedish west coast has shown such trophic cascades due to overfishing of predatory fish and eutrophication. These cascading effects have led to negative consequences for important habitats such as seagrass meadows.

Aim

Our research group is looking for a Masters student to conduct their research project (suggested 60hp) within a larger umbrella project called MarHab. MarHab is an international research project aimed at improving the conservation status of marine habitats in Skagerrak and Kattegat by studying the link between large predatory fish and habitat quality. The project will consist of data collected from the same locations in shallow coastal areas using both baited underwater stereo-video cameras (BRUV), as well as fyke net survey data from the Swedish national environmental monitoring program. Therefore, we are now looking for a Masters student who is interested in doing a method comparison study evaluating the fish assemblages from both methods. There is also the possibility of expanding the project work in order to study the connection between habitat quality and the abundance of predatory fish (predominantly cod).

Over the course of the project you will learn about:

• Video analysis methodology using the leading analysis software EventMeasure
• Handling and analyzing large data sets
• Identifying fish from the Swedish west coast (Skagerrak and Kattegat)

Previous knowledge of Swedish west coast fish species is meriting. Priority will be given to students familiar with data analysis and comfortable working in Excel and R.

More information

Learn more about the MarHab project.

Contact

If you are interested in this exciting project be sure to get in contact by emailing:

ulf.bergstrom@slu.se
diana.perry@slu.se
maria.eggertsen@slu.se

Bachelor project (15 ECTS) or Master project (30/60 ECTS) in biology

Fish welfare: Physiological responses to anaesthisia in brown trout

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
Department of Aquatic Resources (SLU Aqua)
erik.h.petersson@slu.se 010-4784239

Svante Winberg
Uppsala University
svante.winberg@neuro.uu.se
Swedish University of Agricultural Sciences, Department of Anatomy, Physiology and Biochemistry
Svante.winberg@slu.se

Bachelor level (15 ECTS) or Master level (30/60 ECTS) in biology 

Fish welfare: Physiological responses to anaesthesia in zebrafish

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. you will spend many days in the laboratory.

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
Department of Aquatic Resources (SLU Aqua)
erik.h.petersson@slu.se 010-4784239

Svante Winberg
Uppsala University
svante.winberg@neuro.uu.se
Swedish University of Agricultural Sciences, Department of Anatomy, Physiology and Biochemistry
Svante.winberg@slu.se

Master projects in biology (30-60 ECTS)

Ecology and management of the European eel, several projects available!

Background

The European eel, Anguilla anguilla, is red listed as critically endangered due to a steep population decline. Current management efforts aim to reverse this negative development. There are many knowledge gaps regarding everything from ecology, behaviour, and physiology to development of stock assessment parameters. You can help us fill these knowledge gaps!

We have a great variety of masters degree projects and research training / internship related to evaluating and synthesizing information about ecology, management and data collection of the European eel. There are also opportunities to assist in lab work and field activities, such as tagging, fyke-net fishing, dissections, and more.

Project examples

• Evaluating tagging and tracking data of eels in river systems, lakes and in the sea. Students can be involved in the tagging and tracking procedures, depending on time availability. Topics that can be addressed include survival (fisheries induced survival, hydropower induced mortality), movement, long distance migration, etc.
• Improve data collection programs. To monitor the eel stock, data is collected on a number of variables, such as landings, individual length, parasite prevalence, age, etc. Since data collection is time consuming and costly it is important that it is efficient. Any improvements that can be made to the monitoring programs are highly valuable, including 3R aspects.
• Evaluation of management activities such as restocking and fisheries regulations.
• Behavioural and physiological studies.

The work will be supervised by Dr Josefin Sundin and Dr Philip Jacobson. Depending on the project, the student should have an interest in fish ecology, behavioural ecology, fisheries science, data analysis, statistics, and scientific writing.

Location

At the Swedish University of Agricultural Sciences (SLU Aqua) in Drottningholm (Stockholm), Uppsala-Ultuna, or Öregrund. Several projects can also be done online.

Master 60 ECTS

Are you interested in fish, fish ecology and fisheries and would like to do a Masters project in Tanzania?

Our research group is looking for a Masters student to conduct their Master thesis work (suggested 60 ECTS) within our project “FishLinks - Scrutinizing the impact of tourism-driven fish consumption on reef fish communities: a socio-environmental study in tropical seascapes”. The project starts early 2024 with fieldwork planned from August–October in Tanzania.

The focus of the Master project is related to the question of how tourism-driven fishing effects the fish communities on shallow- and deep- coral reefs in Tanzania. Suggested fieldwork sites being Zanzibar (high tourism) and Mafia Island (low tourism). Data collection will mainly be done by deploying baited remote underwater videos (BRUVs) by boat. There are also opportunities within the Masters project to develop methods or research question further. If you think this sounds like an exciting project, do not hesitate to contact:

Seals and cormorants - Top predators in Swedish waters

Suggestions of degree projects

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

• Diet variability
• Methodology (DNA, image analysis)

Monitoring of seals and cormorants

• Photo-ID
• Camera surveillance
• Regional monitoring, e.g. in marine protected areas
• Abundance estimates

Predator-prey dynamics

• Prey selectivity
• Correlations between diet data and fish monitoring data

Contact

Bachelor's level (15 ECTS) or Master's level (30 ECTS)

Developing a socio-ecological model for risk assessment in the Baltic Sea

Thesis work in biology or sustainable development at the Department of Aquatic Resources, Swedish University of Agricultural Sciences

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

Bachelor's level (15 ECTS) or Master's level (30/60 ECTS)

Thesis work in biology or environmental science at the Department of Aquatic Resources, Swedish University of Agricultural Sciences

The round goby is native in the Black sea and Capian Sea but has probably come by ballast water to the Baltic Sea. It was first reported 1990 in the bay of Gdansk where ot is now the most common coastal fish species. In 2008 it was reported in Sweden for the first time, in the archipelago of Karlskrona. It now occurs from Kalmar Sound up to Gävle and also around Gotland and in Gothenburg.

The round goby is an invasive species with high reproduction speed and highly tolerant for environmental stressors. There is a risk that it will compete with other bottom dwelling species and also consume eggs & fry of native species but it can also be a resource for predatory fish and humans. One concern is that it may invade freshwater systems and knowledge about its migrating capability and potential barriers to stop it from entering rivers is needed. In order to utilize the species and develop efficient fishing gear knowledge is needed about the behavior of the fish around different fishing gears. The suggested projects below are experimental studies contributing with knowledge in both these important areas and they are part of the Research project Round goby – turning risk to resource.
All experiments are conducted in Älvkarleby, by the river Dalälven south of Gävle, either at SLU Fisheries Resaerch Station (FFS) or at the Vattenfalls experimental facility Laxeratorn. Depending on your skills and interest the thesis can either be within biology or environmental science with room for personal research questions. The work is flexibel and can be either on candidate or master level.

1. Migration ability (15-60 ETCS), ), practical work is done during 3-6 weeks between August to September in Vattenfall Laxeratorn with potential complementing studies at FFS in October for the 60hp work. In this experiment the ability to migrate in an artificial fisheway at different speed of the water and with different barriers is studied for round goby, trout and bullhead. The study can be done on one or several species depending on the number of credits of the thesis. The work can also be done later in the year on recorded videomaterial from the experiments.
   
   
2. Behaviour around fishing gear (15-60 ETCS), practical work is done during 2-3 weeks in September in the Laxelerator. In this experiment the behehaviour of round goby in the vicinity of a fishging gear is studied with the objective to create efficient methods to catch round goby. The work can also be done later in the year on recorded videomaterial from the experiments.

Contact

Bachelor (15 ECTS) or Master level (30/60 ECTS)

SLU:s Fisheries research station in Älvkarleby produce around 140 000 salmon and trout per year for river Dalälven. A prerequisite for environmental friendly and ethical aquaculture is that reserach is conducted on breeding and rearing of fish. Here we have ongoing reserach and environmental analsysis, and we have aquarieas, creeks and streams for experiments and in addition skilled personel.

We are looking for students for the following projects:

1. Survival of salmon and trout smolt. The cormorant has been identified as a potentially important predator on smolt (salmonid juveniles) but scientific estimates from todays situation in river Dalälven is missing. Since some of the smolt is tagged with pit‐tags it is possible to look for these tags in cormorant colonies. The project involves scanning after pit‐tags in cormorant colonies along the coast but may also include investigations of regurgitates from cormorants or other fisheating birds. The field part is conducted after the breeding season of the birds, i.e. sep‐nov 2020
   
   
2. Enhanced quality of stocked fish. It is desirable that the stocked fish similar to wild fish, but a common problem is that reared fish have damaged finns and also grows to fast and becomes to fat compared to wild fish. In this project the effect of different feedingregimes on condition, survival and fin damage is investigated. Also experiments with different densities of fish can be included. The project can take place almost anytime between march and december.
   
   
3. Historic trends of spawning fish in river Dalälven. Breeding and rearing has taken place at the fisheries resaerch station for amlost 100 years. During this time data on the wild fish migrating from the sea has been collected which makes it possible to study changes in salmon and trout populations in the river in for example size, condition eggsize etc. This project can either be fully theoretical and take place anytime during the year or involve some practical work during either the fishing (aug) or breeding (oct) season.

Depending on previous education and interest the thesis can either be in ecology or environmental analysis and there is room for reserach questions of your own making. The extent is flexibel and the thesis can be done either on candidate or master level.

Contact

Master project in Ecology (30-60 credits)

Study on cost-effective sampling of Baltic cod stomachs for the purpose of multispecies modelling

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.

Contacts

Study on the population structure of herring in the central and western Baltic Sea based on the analysis of growth and otolith shape

Master projedt in Ecology (30-60 credits)

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.

Contacts:

Bachelor (15 ECTS) or Master (30/60 ECTS)

Energy content of the diet of Common guillemots in the Baltic Sea

Common guillemots Uria aalge L. (Am. Eng.: Common Murre) are marine piscivorous top predators with a circumpolar Arctic distribution. Long-term studies have shown that they can be important indicators of changes in marine food webs and ecosystems. The largest Common guillemot colony in the Baltic Sea (~ 15 000 pairs) is at the island of Stora Karlsö. Since 1997, a long-term research program is following this colony and collects annual data on survival, reproduction and diet, among other things.

Obtaining high energy food is a prerequisite for successful breeding and survival in Common guillemots. Several studies have shown that the main food in the Baltic Sea is sprat Sprattus sprattus. New data however show that herring Clupea harengus can also be a significant part of the diet. The energy content of herring of different sizes, and the possible energy content differences between sprat and herring is today unknown. The knowledge is important for evaluating the conservation status of Common guillemots in the Baltic Sea and how much fish that must be left in the sea to ensure survival of seabirds.

The degree thesis focusses on analyzing the energy content of the prey fish of Common guillemots. The fish has already been collected by the Institute of Marine Research in Lysekil. The fish will be analyzed using a bomb calorimeter by the student. This work will take place in Ultuna, Uppsala. The data obtained will be analyzed statistically. The project is planned for Bachelor's level (15 ECTS) but can be expanded into a Master's project as well (30–60 ECTS).

Links
www.balticseabird.com
www.storakarlso.se

Contact

^{Bachelor (15 ECTS)  or Master (30–60 ECTS)}

Evaluating camera monitoring for breeding seabirds

Common guillemots Uria aalge L. (Am. Eng.: Common Murre) are marine piscivorous top predators with a circumpolar Arctic distribution. Long-term studies have shown that they can be important indicators of changes in marine food webs and ecosystems.

The largest Common guillemot colony in the Baltic Sea (~ 15 000 pairs) is at the island of Stora Karlsö. Since 1997, a long-term research program is following this colony and collects annual data on survival, reproduction and diet, among other things. In 2008, a world unique research facility, the Karlsö Auk Lab, was built in the middle of the colony. Scientists can study breeding birds from the inside of the Auk lab at a very close distance (20 – 30 cm). This opens up for extremely detailed studies to a low disturbance.

This degree thesis is about evaluating a new technology for monitoring breeding success in Common guillemots – through automatic cameras. Today breeding is monitored through daily observations to check which eggs and chicks that are present. The new technology builds on images taken at regular intervals, and at a later stage analysis of the images. If this technology is working, there is a big potential of increasing data collection and reduce time spent close to the birds (which also leads to lower disturbance levels). The field work includes both traditional observations studies and collection and analysis of images.

At least four weeks will be spent at Stora Karlsö for field work. The island has a simple field station in the period May – early July. The student will work with experienced field personnel and a field work coordinator. The project is planned for Bachelors level (15 ECTS) but can be expanded into a Masters project as well (30 – 60 ECTS).

Links

www.balticseabird.com
www.storakarlso.se

Contact

In this project you will compare insect biodiversity between two Baltic bays, one where the reed (Phragmites australis) bed has been harvested, and the other un-changed as a control. Over the past years, we have compared changes in bird, fish and macrophyte communities. Now, we will additionally survey insect biodiversity in the same locations. We are looking for a motivated student to collect, process and analyse insect samples, dependent on timing of your thesis.

Background

The common reed (Phragmites australis) is a habitat forming emerging plant found on Baltic and freshwater shorelines. Reed, like trees in a forest, many important ecological functions such as structure, shelter and a source of food for numerous fish, birds, insects and mammals. However, increasing eutrophication has caused reed to invade new habitats and form large monocultures with low biodiversity. The harvesting of reed has the potential to combat monoculture formation and restore habitat heterogeneity, thereby benefiting ecosystems functions and services where reed has become too dense and/or invaded.

Method

In this project, we investigate the impact of reed harvesting on biodiversity by performing surveys of fish, bird, insect and macrophytes in a reed harvested area, and comparing this with the same surveys at a nearby control site. For insects, we will use emergence ans/or swimming traps to collect insects in the two contrasting areas. We are also happy to discuss new or other ideas within the topic of reed harvesting effects on the ecosystem.
Field studies are based in Harg, near Östhammar, with office space available at Ultuna, Uppsala. Feel free to contact with any questions, or if you are interested in doing a bachelor thesis within this project!

Contacts

Competition between perch and roach across sizes and environments–impact on ecological status

Biology 30 credits

Stable isotopes are indicators of individual diet use and can be used to study diet (resource) overlap between species indicate (resource). Perch and roach are the two dominate fish species in Baltic Sea coastal fish communities, and have different ecological functions. Perch is the main predatory fish, but feed on invertebrates as small, whereas roach is an obligate ‘mesopredator’ feeding only on invertebrates. However, as fish change diet over their life-history they compete for common resources at younger ages (sizes). In this project you will study how the diet overlap change across body sizes depend on environmental condition, like watercolor and transparency, temperature and salinity.

To understand how environmental conditions influence the competition and resource use of perch and roach is important to better understand how global change will impact the interaction between our most common fish species, and how management may be adapted to reach good ecological status in coastal areas of the Baltic Sea.

All data has been collected and is ready to be analysed so start time is flexible.

Contact:

Associate professor Magnus Huss, magnus.huss@slu.se

Associate professor Örjan Östman, orjan.ostman@slu.se

Biology 30 or 60 credits

The aim of this project is to investigate changes in perch and pike life history traits to long-term changes in climate and productivity (eutrophication). Whereas the direct short-term impact of environmental variation on life histories are quite well studied, the longer term eco-evolutionary dynamic consequences on predator life-histories are less understood.

To address this you will use back-calculated growth of pike and perch from long-term monitoring data of fish communities in Swedish coastal areas and freshwater lakes. This data serves as great opportunity to develop a framework for a general future understanding of how large scale environmental variation will affect life-history traits and reaction norms of predatory fish in a changing world. This knowledge is both important to understand the long-term anthropogenic impact on natural communities, and is also relevant to reach the environmental targets set within Sweden and the European Union.

Project start is flexible data collection is ready. Therefore a large part of thesis project will be statistical analyses and model simulations.

Contact

Associated professor Örjan Östman, orjan.ostman@slu.se

Masters thesis 30-60 hp

Background

Marine ecosystems are under immense pressure from a wide range of human activities, such as fishing, shipping, coastal development, and pollution, among others. One of the greatest challenges faced by conservation scientists and practitioners is the task of mapping these activities so that we may determine which ecosystems are most threatened and where we should focus our conservation efforts. However, in recent years, exciting developments in the field of artificial intelligence (AI) offer a promising solution to this challenge.

Project description

In this project, the student will use neural networks and satellite imagery to produce maps of human activities in the ocean. The objective will be to map specific activities that are recognizable through satellite images, which may include small-scale fishing, mariculture, and/or oil and gas activities. The study region and scale are flexible, but will ideally include the Western Indian Ocean, the South China Sea, the Gulf of Thailand, and/or the Baltic Sea.

The student should have a strong interest in modelling/machine learning, coding (ideally in R or Python), and conservation. It is also advantageous to have some knowledge of marine ecosystems, but this is not essential. The project may be undertaken at any time and falls within larger ongoing projects in the Baltic Sea, the Western Indian Ocean, and South-East Asia. As such, the student can expect to be involved in a highly collaborative research environment.

Contact

Edmond Sacre

Department of Aquatic Resources, Institute of Coastal Research, Swedish University of Agricultural Sciences

edmond.sacre@slu.se, +46 730855441

Monitoring populations by fishing gear – A camera study of the European lobster

Master thesis 30/60 credits

The European lobster (Homarus gammarus) occurs along the entire Swedish west coast down to the northern part of the Sound, and lives mainly on rocky substrates in crevices and dugouts between rocks and gravel. The lobster population along the Swedish coast is considered to be one single stock, but large local differences in density may occur. Fishing for European lobster is extensive, but catch per effort (the number of lobsters caught per pot) decreased sharply during the 1950s and 1960s and has since remained at a stable low level according to catch data from lobster fishermen in Bohuslän. New legislation limiting the lobster fishery was passed in 2017, yet the stock is still considered to be overfished: The overall stock analysis (Fish Barometer 2024) indicates high fishing mortality over long periods, and low productivity, with the result that the stock is not within safe biological limits. To provide management with a strong basis for decision-making, we are working to increase the knowledge of European lobster biology and behavior.

Every year, the Department of Aquatic Resources (SLU Aqua) conducts a lobster survey in both no-take and fished areas to provide fisheries independent data on biological parameters of the Swedish lobster population. In addition to SLU's survey, volunteer fishermen participate in the citizen science project; LOBSERVE, which enables the collection of catch data and size along a larger geographical area. Lobster catch can be used as an index of density, and thus of stock status, and can be compared between areas and over time if the fishing is standardized and carried out at the same time of year. If a pot is left fishing (soaked) for a longer period, the pot will eventually be saturated as lobsters are no longer attracted to the bait or choose not to enter due to e.g., competition. CPUE needs to be standardized to soak time to be comparable. With the help of a camera study, we want to find out what happens at and around the cage. We want to investigate questions such as

• What influences a lobster to enter a pot?
• At what rate is a pot getting saturated?
• At what point do lobsters stop entering the cage?
• Do lobsters' propensity to enter a cage with other lobsters differ between fished and no-take areas?

We offer the opportunity to do a degree project with focus on European lobsters, using camera-rigged pots to study the behavior of lobsters around pots and also factors leading to saturation of pots. We are looking for a highly motivated student with an interest in fisheries ecology and animal behavior. Experience with dynamic modelling and R is an advantage. The work includes fieldwork, analysis of collected video material and data analysis. SLU's lobster survey occurs in Lysekil in August, and the student will be part of the crew while deploying the lobster pots rigged for video.

Contact

Hege Sande, hege.sande@slu.se 

Andreas Sundelöf, Andreas.sundelof@slu.se