Karl Øystein Gjelland

Norwegian Institute for Nature Research | NINA · Department of Arctic Ecology

Movement diversity within species represent an important but often neglected, component of biodiversity that affects ecological and genetic interactions, as well as the productivity of exploited systems. By combining individual tracking data from acoustic telemetry with novel genetic analyses, we describe the movement diversity of two Atlantic cod...

The global population of European eel (Anguilla anguilla) is rapidly declining, and migration barriers in rivers are believed to be one of several key causes. While progress has been made in the development of bypass solutions, they are often constructed based on a limited knowledge on swimming behaviour. A bypass close to the stream bed is often r...

To understand the spatiotemporal overlap in the habitat use of sympatric predators, we studied longitudinal activity and reservoir section and depth use of pike (Esox lucius), pikeperch (Sander lucioperca) and catfish (Silurus glanis) in the Římov Reservoir, using an autonomous telemetry system for 11 months. We found significant differences among...

Internal seiches are common in stratified lakes, with significant effects on stratification patterns, hydrodynamics and vertical nutrient transport. In particular, seiches can change the vertical distribution of the thermocline and the cold hypolimnetic and warm epilimnetic water masses by several metres on a timescale of a few hours, leading to ra...

Understanding animal movement is essential to elucidate how animals interact, survive, and thrive in a changing world. Recent technological advances in data collection and management have transformed our understanding of animal “movement ecology” (the integrated study of organismal movement), creating a big-data discipline that benefits from rapid,...

This datasheet on Coregonus albula covers Identity, Overview, Distribution, Dispersal, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control, Management, Further Information.

To understand the conditions of coexistence in multiple-species predator community, we studied longitudinal and vertical movement of pike (Esox lucius), pikeperch (Sander lucioperca) and catfish (Silurus glanis) in the Rimov Reservoir, using an autonomous telemetry system for 11 months. We found significant differences among these three species in...

The abundance of the parasitic salmon louse has increased with the growth in aquaculture of salmonids in open net pens. This represents a threat to wild salmonid populations as well as a key limiting factor for salmon farming. The Norwegian ‘traffic light’ management system for salmon farming aims to increase aquaculture production while securing s...

Structural complexity is known to influence prey behaviour, mortality and population structure, but the effects on predators have received less attention. We tested whether contrasting structural complexity in two newly colonised lakes (low structural complexity lake—LSC; high structural complexity—HSC) was associated with contrasting behaviour in...

Maintaining standing genetic variation is a challenge in human-dominated landscapes. We used genetic (i.e., 16 short tandem repeats) and morphological (i.e., length and weight) measurements of 593 contemporary and historical brown trout (Salmo trutta) samples to study fine-scale and short-term impacts of different management practices. These had ch...

Internal seiches are common in stratified lakes, with significant effects on stratification patterns, hydrodynamics and vertical nutrient transport. In particular, seiche can change the vertical distribution of the thermocline and the cold hypolimnetic and warm epilimnetic water masses by several meters on a timescale of a few hours. The results ar...

Movement ecology is increasingly relying on experimental approaches and hypothesis testing to reveal how, when, where, why, and which animals move. Movement of megafauna is inherently interesting but many of the fundamental questions of movement ecology can be efficiently tested in study systems with high degrees of control. Lakes can be seen as mi...

Fish swimming performance is strongly influenced by flow hydrodynamics, but little is known about the relation between fine-scale fish movements and hydrodynamics based on in-situ investigations. In the presented study, we validated the etho-hydraulic fish swimming direction model presented in the River Mandal from Southern Norway, using similar be...

Biodiversity assessments using molecular identification of organisms through high-throughput sequencing techniques have been a game changer in ecosystem monitoring, providing increased taxonomic resolution, more objective identifications, potential cost reductions, and reduced processing times. The use of DNA metabarcoding of bulk samples and envir...

Structural complexity is known to influence prey behaviour, mortality and population structure, but the effects on predators has received less attention. We tested whether contrasting structural complexity in two newly colonised lakes (low structural complexity lake – LSC; high structural complexity - HSC) was associated with contrasting behaviour...

Repeat spawners constitute an important component of Atlantic salmon populations, but survival of post-spawning individuals (kelts) are often compromised by anthropogenic structures such as hydropower plants (HPPs). Potential effects of HPPs include migration delays and associated increased energy depletion, which potentially results in increased o...

https://brage.nina.no/nina-xmlui/handle/11250/2658466

Atlantic salmon in aquaculture act as reservoir hosts and vectors of parasites like salmon lice and this parasite is shown to harm wild salmonid populations. In this study, n = 29,817 tagged Atlantic salmon were studied in four release trials. Half of the released fish were given prophylactic treatment against lice, the other half represented sham...

The R package yaps was introduced in 2017 as a transparent open source alternative to closed source manufacturer-provided solutions to estimate positions of fish (and other aquatic animals) tagged with acoustic transmitters. Although yaps is open source and transparent, the process from raw detections to final tracks has proved to be challenging fo...

Anthropogenic structures in rivers are major threats for fish migration and effective mitigation is imperative given the worldwide expansion of such structures. Fish behaviour is strongly influenced by hydrodynamics, but little is known on the relation between hydraulics and fish fine scale-movement. We combined 3D Computational fluid dynamics mode...

Permanent link to the report: http://hdl.handle.net/11250/2608224

There is no generic solution to establish safe passage of downstream migrating fish passed hydropower facilities and mitigation measures are species‐ and site‐specific. Development of solutions is thus often based on “trial and error” and modelling based approaches may significantly reduce cost and time to arrive at successful mitigation. Here we e...

Understanding Atlantic salmon Salmo salar post-smolt coastal migration behaviour is crucial for predicting their exposure to ecological challenges such as the parasite salmon louse Lepeophtheirus salmonis. We compared the migration of acoustically tagged, hatchery-reared Atlantic salmon post-smolts of wild and domesticated origins from the inner, m...

Sea trout face growth–mortality trade-offs when entering the sea to feed. Salmon lice epizootics resulting from aquaculture have shifted these trade-offs, as salmon lice might both increase mortality and reduce growth of sea trout. We studied mortality and behavioural adaptations of wild sea trout in a large-scale experiment with acoustic telemetry...

Aquatic positional telemetry offers vast opportunities to study in vivo behaviour of wild animals, but there is room for improvement in the data quality provided by current procedures for estimating positions. Here we present a novel positioning method called YAPS (Yet Another Positioning Solver), involving Maximum Likelihood analysis of a state-sp...

Methods that aid in understanding the variation in the detection probability in acoustic telemetry can aid proper interpretations of data derived using such systems. In their recent paper, Huveneers et al . ( Methods in Ecology and Evolution , 7, 825‐835, 2016) claim that a general detection probability model (Gjelland & Hedger, Methods in Ecology...

The monogenean parasite Gyrodactylus salaris poses serious threats to many Atlantic salmon populations and presents many conservation and management questions/foci and challenges. It is therefore critical to identify potential vectors for infection. To test whether hybrids of native Atlantic salmon (Salmo salar) × brown trout (Salmo trutta) are sui...

Arctic charr (Salvelinus alpinus) is generally considered an inferior piscivore compared to brown trout (Salmo trutta). However, we demonstrate that a recently described profundal spawning piscivore PP-morph of Arctic charr in a subarctic lake has evolved typical piscivore traits (i.e. large jaws, robust skulls), similar to the co-occurring brown t...

While fine mesh trash racks constitute a safe barrier for downstream migrating smolts, such racks can be expensive and technically difficult to retrofit at hydropower intakes. Alternatively, a combination of attraction and repulsion measures can successfully pass fish by the intake and into safe corridors. At the Laudal hydropower plant in the rive...

Tracking individual variation in the dynamics of parasite infections in wild populations is often complicated by lack of knowledge of the epidemiological history of hosts. Whereas the dynamics and development of Gyrodactylus salaris Malmberg, 1957, on Atlantic salmon, Salmo salar L., are known from laboratory studies, knowledge about infection deve...

Knowledge of predator–prey dynamics is essential to understand ecosystem functioning. Quantification of such interactions is important for fisheries management, in particular in the case of stocking programmes. Here, food consumption rates (FCR) were quantified for wild and stocked piscivorous brown trout, Salmo trutta L., in three subarctic lakes...

ABSTRACT: Salmon lice Lepeophtheirus salmonis Krøyer may affect survival and growth of anadromous salmonids through physiological stress and/or behavioural changes. Using acoustic telemetry tracking, we investigated the behaviour of 30 infected sea trout Salmo trutta throughout the summer in a fjord with very high salmon lice infection pressure. Mo...

Målsetningen for undersøkelsene i Osensjøen i 2013 var å fastslå status for fiskebestandene mer enn 30 år etter åpningen av Osa kraftverk i 1981. Mer spesifikt skulle vi også vurdere mulige effekter av planlagte endringer i reguleringen, dvs. overføring av vann fra de øvre delene av Flisas nedbørfelt til sørenden av Osensjøen, og en ytterligere sen...

Invasion of exotic species has caused the loss of biodiversity and imparts evolutionary and ecological changes in the introduced systems. In northern Fennoscandia, European whitefish (Coregonus lavaretus (L.)) is a highly polymorphic species displaying adaptive radiations into partially reproductively isolated and thus genetically differentiated sy...

Invasions of non-native species represent a global problem of great scientific interest. Here we study in detail the response in population and life history characteristics of closely related native species, with divergent habitat preferences, that are impacted by an invading species over a sufficient time period to allow a new stable state to beco...

1. Environmental factors, such as wind, may have a strong influence on the detection probability and detection rate of acoustic telemetry tags. The effect of environmental factors may obscure biological effects and distort the interpretation of acoustic telemetry data. 2. This study was undertaken with fish internally tagged with acoustic transmit...

Species invasions can have wide-ranging biological and socio-economic effects and are generally unwanted by legislation. Identification of the source population as well as the ecology and genetics of both the invader population and the receiving community is of crucial importance. The rapid invasion of a small coregonid fish vendace (Coregonus albu...

If a pelagic ecosystem is invaded by an efficient planktivorous fish, competition theory predicts that habitat and/or diet segregation should occur if the invader and native planktivores are to co-exist. We compared the diet and pelagic habitat use between invading vendace (Coregonus albula) and two native morphs of whitefish (Coregonus lavaretus)...

We explore the long-term developments in population biology and life history during the invasion and establishment of the fish species vendace Coreg-onus albula in a subarctic watercourse by comparing life-history traits and molecular genetic estimates between the source and the colonist population. The two populations exhibited highly contrasting...

Gill raker divergence is a general pattern in adaptive radiations of postglacial fish, but few studies have addressed the adaptive significance of this morphological trait in foraging and eco-evolutionary interactions among predator and prey. Here, a set of subarctic lakes along a diversifying gradient of coregonids was used as the natural setting...

Metallurgic industry is a source of serious environmental pollution related to the emission of heavy metals. Freshwater systems are focal points for pollution, acting as sinks for contaminants that may end up in fish and humans. The Pasvik watercourse in the border area between Finland, Norway and Russia is located in the vicinity of the Pechengani...

Following invasion and establishment in a subarctic watercourse, small-sized vendace Coregonus albula were surprisingly found to include fish prey in their diet. The zooplankton resource was severely depleted and only made a minor dietary contribution.

Visually foraging planktivorous fish are prey of visual predators, and their foraging behaviour may be affected by light levels both in terms of gain and risk. The large seasonal change in day length throughout a subarctic summer at 69 degrees N was used to show the influence of light on diel vertical migration (DVM) and shoaling patterns in a plan...

Predation has a fundamental role in aquatic ecosystems, but the relative importance of factors governing prey selection by predators remains controversial. In this study, we contrast five lakes of a subarctic watershed to explore how prey community characteristics affect prey selection and growth rate of the common top predator, brown trout (Salmo...

Vendace Coregonus albula has invaded the subarctic Pasvik hydrosystem, northern Norway and Russia, after being translocated from its native Finnish range into Lake Inari (Finland), upstream of Pasvik. The development of the invader and the effects on two native lake communities in the upstream and downstream part of the hydrosystem, respectively, h...

Swimming speed of pelagic whitefish (Coregonus lavaretus) and vendace (Coregonus albula) was studied in two subarctic lakes at 69°N in northern Norway in June, August and September 2000. At this latitude, the light regime changes strongly during the summer months, from 24 hrs of daylight in June to 14 hrs in September. Swimming fish were monitored...

The diel vertical migration of whitefish (Coregonus lavaretus) and vendace (Coregonus albula) was studied in a lake using bottom mounted echosounder transducers beaming upwards. Significant gas release was observed when the fish were ascending towards the surface during the dusk. From mobile hydroacoustic surveys it was found that the target streng...