Two papers in Animal Conservation

Posted by Karl Filipsson | Papers

Two papers from NRRV were recently published in the journal Animal Conservation. The first paper presents a field study on how sedimentation affects brown trout (Salmo trutta) fry emergence in relation to freshwater pearl mussel (Margaritifera margaritifera) recruitment. The second paper presents a combined field and laboratory study on passage solutions for upstream-migrating eels (Anguilla anguilla).

 

Sedimentation affects emergence rate of host fish fry in unionoid mussel streams

Martin Österling

 

In the abstract, the author writes:

Freshwater pearl mussel, Margaritifera margaritifera

“Free-living, sympatric sedentary life stages of hosts and parasites are often adapted to similar environmental conditions. When the environment where these life stages occur is disturbed, both species can decline, causing strong negative effects on the parasitic species. For the highly threatened unionoid mussels with their larval parasitic life stage on fish, habitat degradation may simultaneously affect the conditions for the sedentary host fish eggs and the juvenile mussels in the sediment. This study provides novel information on the effect of sedimentation on the emergence rate of yolk sac fry, and its relation to mussel recruitment in two drainage basins, and is exemplified by the brown trout Salmo trutta, host fish for the threatened freshwater pearl mussel Margaritifera margaritifera. The results imply that turbidity and sedimentation can reduce the survival of trout eggs and yolk sac fry emergence rate regardless of trout strain and drainage basin. The results further suggest that low yolk sac fry emergence rates reduce the potential for mussel infestation and recruitment. The results indicate a year round negative effect of sedimentation, having strong and combined direct and indirect effects on juvenile mussel recruitment. Conservation measures that reduce anthropogenic sediment transportation into streams are a key factor for the conservation of mussels and their host fish.”

Access the paper here, or contact the author.

 

Climbing the ladder: an evaluation of three different anguillid eel climbing substrata and placement of upstream passage solutions at migration barriers

Johan Watz, Anders Nilsson, Erik Degerman, Carl Tamario and Olle Calles

 

European eel, Anguilla anguilla. Photo: Jörgen Wiklund

In the abstract, the authors write:

“Conservation programmes for endangered, long-lived and migratory species often have to target multiple life stages. The bottlenecks associated with the survival of juvenile anguillid eels migrating into inland waters, the survival and growth of the freshwater life stage, as well as the recruitment and survival of silver eels, migrating back to the ocean to spawn, must be resolved. In this study, we focus on the efficiency of passage solutions for upstream-migrating juveniles. Such solutions can consist of inclined ramps lined with wetted climbing substrata. We evaluated different commonly used substrata in a controlled experiment, recorded eel behaviour at the entrance of the ramp with infrared videography and validated the experimental results at a hydropower dam, where we also investigated the effects of ramp placement on performance. In the experiment on eel substratum selection, 40% of the eels passed in lanes with studded substratum, whereas only 21 and 5% passed using open weave and bristle substrata respectively. Video analysis revealed that the studded substratum attracted more approaches and initiated climbs than the other substrata, but once a climb had been initiated, passage success rates did not differ between substrata. Eels using the studded substratum climbed 26% faster than those using the bristle substratum and almost four times as fast as those climbing in the open weave. The superior performance of the studded substratum was supported by data from the field validation. Moreover, ramps positioned by the bank with low water velocities caught the most eels, but proximity to the dam had no effect on performance. To strengthen the European eel population, more juveniles need to reach their freshwater feeding grounds. A critical step to achieve this increase is to equip upstream passage solutions with suitable substrata and to optimize ramp placement at migration obstacles.”

Access the paper here, or contact any of the authors.

As part of the Gullspång salmon and -trout monitoring program, a group of people from the management group, Gammelkroppa Lax and Jyväskylä University/Fortum perform redd surveys in the river every year in early December. The salmon and trout in the Gullspång River spawn fairly late in the season, first trout in October-early November and then salmon in November until around the beginning of December.

This year I was invited to assist in the redd surveys, which I of course said yes to! Any chance to learn more about the Gullspång salmon and -trout is valuable for the model I’m making. Plus, it’s nice to get out of the office, even when the temperature is close to zero. And it’s also very inspiring to meet other people who are studying the Gullspång salmonids.

 

Lilla Åråsforsen. With sunrise at around 8:30 and sundown at 15:30, we had to be efficient to cover the three areas (about 6.4 hectares) in the precious daylight hours the four days.

 

So, we started by the Årås bay (Åråsviken) on Tuesday, and slowly worked our way upstream. With layers upon layers (upon layers…etc.) under our waders, and thick, wadded rubber gloves we walked gracefully around in the three spawning areas – Lilla & Stora Åråsforsen and Gullspångsforsen- to look for anything that could be a fish-made structure in the gravel beds. Sometimes we had redds that looked like textbook examples of redds, other times they didn’t look like anything. To confirm or disprove that it was an active redd, we did some careful digging in the pit itself to see if it contained at least two live eggs. The females often do some test diggings before the “real deal”.

We marked confirmed redds with conspicuously colored stones so that they can be found again in the spring; their location was also mapped with a GPS. Initially, we started with Finnish marking stones, but to our slight surprise they ran out (see why further down). We therefore had to settle with slightly lighter Swedish stones the last few days. Sadly, Norway was not represented with any stones (but we’ll see next year).

We also took measurements of the dimensions of the redds, as well as the depth and velocities along the gradient between start of pit and end of tail. I quickly took the role of propeller lady, taking the flow velocity measurements with NRRV’s OTT meters. It was interesting to see how much higher the velocity generally was in the tail compared to in the pit.

 

Horseshoe-formed tail of a large redd in Lilla Åråsforsen rapids marked with a white-painted and numbered stone. The marking stones were bought from a local stone dealer in Finland and brought to Gullspång.

 

I’ve saved the best for the end: the reason why we kept running out of marking stones was that we counted a record number of redds this year! We found redds also where they usually are not found, in total around 190 of them! It’s a careful victory, because we don’t yet know how many of them are salmon respective trout redds. But it was a nice early Christmas present, and I’m glad I joined!

/Kristine Lund Björnås

 

Learn more:

Management report on the monitoring results on Gullspång salmon and –trout in 2017:

http://extra.lansstyrelsen.se/vanern/Sv/publikationer/2018-2020/Sidor/Gullsp%C3%A5ngs%C3%A4lven_2017.aspx

 

Salmon females design their redds in a sophisticated way to increase velocities and dissolved oxygen to the egg pockets as shown with a 3D fluid dynamic model:

Tonina, D. & Buffington, J.M. (2009). Doi:10.1139/F09-146

River Rottnan in winter

Johan Watz, Olle Calles, Niclas Carlsson, Teemu Collin, Ari Huusko, Jörgen Johnsson, Anders Nilsson, Johnny Norrgård and Daniel Nyqvist recently published the paper “Wood addition in the hatchery and river environments affects post-release performance of overwintering brown trout” in the journal Freshwater Biology.

In the abstract, the authors write:

“1. Habitat structural complexity affects the behaviour and physiology of individuals, and responses to the  environment can be immediate or influence performance later in life through delayed effects.

2. Here, we investigated how structural enrichment, both pre-release in the hatchery rearing environment and post-release in the wild, influenced winter growth and site fidelity of brown trout stocked into side channels of a regulated river.

3. Experiencing structural enrichment in the rearing environment during 3 months in autumn had no pre-release effect on growth, but a delayed positive effect after release during the subsequent winter. Moreover, trout recaptured in wood-treated sections of the side channels had grown more than trout recaptured in control sections. Wood enrichment in the side channels also increased overwinter site fidelity.

Johan Watz at the field site.

4. These results show that adding structure during a relatively short period may alter growth trajectories, and adding wood to side channels is a cost-effective method to enhance winter habitat carrying capacity for  juvenile salmonids in regulated rivers.”

Access the paper here.

Teemu Collin tracking trout at the field site.

 

Dead wood in a side channel of the river.

 

River Rottnan.

Burbot, Lota lota

On Tuesday 3 April 2018, Karl Filipsson, PhD student at Karlstad University, will give a talk titled “The effects of temperature and light conditions during winter on antipredator responses of juvenile brown trout against burbot”. The seminar will start at 13:15 in room 5F416 at Karlstad University. Everyone is welcome to attend the seminar.

The book, “Brown Trout: Biology, Ecology and Management”, edit by Javier Lobón-Cerviá and Nuria Sanz was recently published. The book is described as “a comprehensive guide to the most current research, history, genetics and ecology of the brown trout including challenging environmental problems”. John Piccolo and Johan Watz, both researchers at Karlstad University, have written the chapter Foraging Behaviour of Brown Trout: A Model Species For Linking Individual Ecology to Population Dynamics? They summarize their chapter as follows:

“Within the discipline of stream fish ecology, population-, community-, and even ecosystem-level patterns and processes have assumed an increasingly larger role in recent decades. It might be argued, however, that research on the behaviour of individual organisms ought still to play a major role in ecology; it is upon the individual, after all, that natural selection acts. Thus, one might reasonably expect that observing an individual fish’s behaviour should lead to robust conclusions about the fitness costs and benefits that animals must trade-off in order to achieve reproductive success. And ultimately, it is those individuals that achieve the greatest direct fitness that ought to, on average, drive the population-level processes that have attracted so much of stream fish ecologists’ attention in recent years. In linking behavioral- to population-level ecology, we are in luck when it comes to the brown trout – there is no stream fish species whose population ecology is better quantified, nor are there many species that have received more attention from behavioural ecologists. Thus we might consider the brown trout as a model species for developing the ecological understanding of how natural selection (e.g. individual, fitness-based decisions) acts to regulate stream fish populations. To forward this concept, a further development of a quantitative approach to foraging behaviour is warranted. In this chapter we review and synthesize the literature on brown trout foraging experiments with an eye towards identifying the knowledge gaps that remain to be filled in order for ecologists to quantify the fitness costs and benefits of foraging behaviour.”

The book is available (but expensive) here. For access to the specific book chapter, email John Piccolo or Johan Watz.

Kristine Lund Bjørnås recently started a licentiate position within the NRRV-research group at Karlstad University. Here she briefly presents her background and what she plans to do during her licentiate:

“Hello! My name is Kristine Lund Bjørnås and I recently started a licentiate degree (which is ½ a PhD) within the NRRV group at Karlstad University. Like Klarälven I started in Norway before I slowly found my way to Karlstad. I grew up in a town called Melhus in Mid-Norway, with one of the country’s best salmon rivers – Gaula – as a neighbour. My interest in anadromous salmonid conservation arose naturally. I have since lived and studied in Trondheim, Ås, Reykjavík, Steinkjer, and Lund before moving to Värmland.

Before Kristine Lund Bjørnås started her licentiate position she volunteered at a bird ringing station in Southern Norway. Here they have caught and ringed a young male sparrowhawk.

In my licentiate project, I am studying the spatial ecology of brown trout in local streams. My goal is to pinpoint the most cost-effective and informative method to predict living conditions for juveniles under different flow regimes and after river restoration measures. Thinking back to my hometown river system, the main focus is on the adults of the anadromous trout populations and on their conditions for spawning. The conditions for juveniles is often overlooked, but for efficient conservation of these threatened populations, we need to consider both. Which brings me back to my project. I will test if it is possible to predict the distribution, density, and growth of juveniles using habitat and fitness-based models of increasing complexity. The simplest models use physical habitat and hydrology to estimate usable area of a stream section; the most complex models – so-called drift-foraging or net energy intake models – also incorporate food (drifting insects) and foraging theory. By adding spatial and temporal variations in drift concentration given a flow, the models can be made more realistic – although a model will always be a simplification of the entire complexity of the natural world. I am sure to make mistakes, but to avoid repeating previous ones, I am doing a review of studies attempting to model drift- foraging in streams. I will start my main fieldwork in the late spring of 2018. There will be opportunities to join in on that, so stay tuned!

Autumn field survey in Örebro county. Kristine Lund Bjørnås sampling with visiting professor Kurt Fausch in the background. Photo: Carola Gutfreund.

I did my Master in Conservation Biology at Lund University. I am very interested in the broad societal and ethical discussions that arise in conservation biology. I wrote my thesis on spatial variations and potential drivers of population trends of birds breeding along the Swedish coast – in general, “warm-adapted” bird species (measured in species temperature index STI) have increased while “cold-adapted” species have declined over the last 27 years.”

Fiskvandring i Nianån

Posted by Daniel Nyqvist | Dam removal

Som en del av en större studie på ekologiska effekter av dammutrivning studerar NRRV, tillsammans med Hudiksvalls kommun, fiskvandring i Nianån, Hälsingland. I somras revs en kraftverksdamm, belägen 70 m från åns mynning, ut och vi studerar nu vandrande fisk i vattendraget. Vi har under hösten fångat och märkt både öring och flodnejonöga, och hopppas att följa upp med studier av vårvandrande fisk – såsom abborre, mört och id – under våren. Tidigare tog det stopp redan efter 70 m, men hur beter sig fisken i den nya situationen?

Öring vandrar under hösten upp i Nianån för att leka. Lekvandrande öring har fångats med hjälp av olika ryssjor i åns mynning och märkts med radiosändare. Vi har sedan kunnat följa dess rörelser i ån med hjälp av både manuell pejlning och fasta loggerstationer. Senare ska via analysera öringsens lekvandring i ån, bland annat hur den utforskar området uppströms den nyss utrivna dammen.

Flodnejonögon vandrar upp i ån på hösten, övervintrar i vattendraget och leker under den kommande våren. Vi fångar nejonögonen med så kallade nättingfällor vid åns mynning och märker dem med PIT-tags (små märken utan batteri som aktiveras när de kommer i närheten av en antenn, de fungerar enligt samma princip som många passerkort). Vi släpper sedan ut dem nedströms fällorna och genom att återfånga en del av de märkta nejonögonen kan vi få en bild av mängden nejonögon i ån. Vi har dessutom fällor uppströms den utrivna dammen, och kommer på så sätt undersöka huruvida nejonögonen utforskar dess områden. Genom att under vintern pejla nejonögonen manuellt kan vi också undersöka var i ån de övervintrar.

Förutom att studera fiskens beteende är vi också intresserade av vidare ekologiska frågor såsom hur fisksamhället, vegetationen och födoväven förändras som ett resultat av dammutrivningen.

I går visade Mitt i Naturen på SVT ett inslag om dammutrivningen i Nianån. I inslaget visas bilder från dammutrivningen och Johan Andreasson, från Hudiksvalls kommun, intevjuas om utrivningens bakgrund och målsättning. Se reportaget här.

Jessica Dolk, Karlstads universitet, och Johan Andreasson, Hudiksvalls kommun, märker en öring. I bakgrunden syns en ryssjorna som fångar den lekvandrande öringen.

Den radiomärkta öringens rörelser i ån övervakas med fasta loggerstationer.

Flodnejonögon fångas i en s.k nättingfälla.

Jessica Dolk vittjar en nättingfälla.

Ett flodnejonöga väntar på att märkas.

karl

Karl Filipsson, PhD-student at Karlstad University.

Karl Filipsson has recently joined the NRRV-research group. Here he writes about his previous work and what he intends to do as a PhD-student at Karlstad University:

My name is Karl Filipsson and I recently started my PhD in the River Ecology and Management Research Group (NRRV) at Karlstad University, where I am going to study the winter ecology of stream fishes in relation to climate change. I have a master’s degree in biology from the University of Gothenburg, with focus on aquatic and evolutionary ecology. Although I have a broad interest in fish ecology and behavior, I have developed a special interest for fish inhabiting streams. In my master project I studied the effect of parasitic freshwater pearl mussel (Margaritifera margaritifera) larvae on brown trout (Salmo trutta). The project mainly examined behavioral responses in the host fish, but growth and cardiorespiratory parameters were measured as well.

In my PhD I will use an experimental approach to look at the consequences of warmer winters on predator-prey interactions and early life-history performance in stream fishes. I will use brown trout and burbot (Lota lota) as model species. River ecosystems and associated fish populations have a significant role in providing important ecosystem services. Therefore, it is of great importance to acquire knowledge on the winter ecology of stream fishes under climate change. Hopefully, results from this project will not only elucidate how stream fishes are adapted to winter conditions and respond to environmental change, but will also provide information for stakeholders and decision makers on how to manage fish populations and stream ecosystems in a future influenced by global climate change.

In addition to research, I have a great interest in scientific outreach. I have previously been working at the science center Universeum in Gothenburg and as scuba diving guide, and I am very keen on taking on the challenge to communicate research to the broader public and to be teaching in higher education.”

Some of Karls previous work on the interaction between juvenile brown trout and frehswater pearl mussel larvae is published in the scientific articles Encystment of parasitic freshwater pearl mussel (Margaritifera margaritifera) larvae coincides with increased metabolic rate and haematocrit in juvenile brown trout (Salmo trutta) and Heavy loads of parasitic freshwater pearl mussel (Margaritifera margaritifera L.) larvae impair foraging, activity and dominance performance in juvenile brown trout (Salmo trutta L.).

 

trout_jw

A juvenile brown trout in the experimental flume.

Johan Watz, postdoc at Karlstad University, recently published the scientific article “Stress responses of juvenile brown trout under winter conditions in a laboratory stream” in the journal Hydrobiologia. In the abstract he writes: “Winter can be a challenging period for fish in northern temperate rivers and streams, particularly in those that are channelized, structurally simple or regulated by, for instance, hydropower. In these systems, dynamic sub-surface ice formation commonly occurs and stable periods with ice cover may be short. Under these adverse conditions, access to shelters has been shown to be an important factor that influences overwinter survival, and exclusion from shelters by anchor ice may cause stress. Here, stress responses of juvenile brown trout under simulated winter conditions in an artificial stream were studied. Trout were subjected to three treatments in which the trout (1) were excluded from an instream wood shelter, simulating the effects of anchor ice, (2) had access to the shelter or (3) had surface ice cover in addition to the shelter. There was a positive correlation between ventilation frequency and plasma cortisol concentration. Trout without access to shelter had 30% higher ventilation frequency than trout with instream shelter and surface ice, but no differences in cortisol concentration or stress colour were found between the treatments. River regulation that reduces surface ice and increases anchor ice formation may lead to increased stress and consequently reduce overwinter survival rates.”. 

Access the paper here: Stress responses of juvenile brown trout under winter conditions in a laboratory stream.

Tomorrow (Tuesday), February 28, David Aldvén from the University of Gothenburg and Vattenfall AB, will give a seminar titled ”Downstream migration of anadromous brown trout”. David Aldvén finished his PhD with a thesis titled ”Migration in anadromous brown trout”. The frame of his thesis is available online here.

The seminar will be given at 13:30 in room 5F416 on Karlstad University. Everyone is welcome to attend!