WTT Blog - Tagged with PhD

Reflecting on NoWPaS 2018

Posted on March 27, 2018

Reflecting on NoWPaS 2018

Quite a few of our guest bloggers recently have been at the same conference. Unfortunately, I could only follow the key scientific revelations via Twitter from afar but I have been alerted to some work of which I was previously unaware, so I am hoping to establish contact with those people and perhaps they will contribute a blog or two in the near future. Here, Jess Marsh (she of the water crowfoot and salmonid community research) has kindly offered to tell us briefly about NoWPas.

A week after the 14th annual NoWPaS workshop was wrapped up in spectacular style with a traditional Finnish nuotio, or campfire, we are reflecting on an inspiring week of exciting salmonid research, new experiences and friendships.

NoWPaS 2018 participants at Oulanka Research Station, Finland. Photo taken by Angus Lothian

Communities created by crowfoot?

Posted on January 22, 2018

Communities created by crowfoot?

There are few more captivating sights than a river reach swathed in water crowfoot flowers, for what delights might be hidden beneath?  William Barnes (1801–1886) was certainly inspired:

O small-feac’d flow’r that now dost bloom,To stud wi’ white the shallow Frome,An’ leäve the clote to spread his flow’rOn darksome pools o’ stwoneless Stour,When sof’ly-rizèn airs do coolThe water in the sheenèn pool,Thy beds o’ snow white buds do gleamSo feäir upon the sky-blue stream,As whitest clouds, a-hangèn highAvore the blueness of the sky

This humble member of the buttercup family is considered by ecologists as an autogenic engineer: it can change the surrounding environment via its own physical structure. While many people have tried to study where and why water crowfoot grows, especially in relation to nutrients, few have considered how the plant influences the assemblages of organisms around it. Cue Jessica Marsh’s PhD study….

Should I stay or should I go?

Posted on January 05, 2018

Should I stay or should I go?

'Can I migrate?' is a question that we at WTT often raise on behalf of fish. In most instances, this question is associated with two physical factors. One is whether there is sufficient water in the river for fish to move through; a problem exacerbated in the southern parts of the UK by abstraction pressures. The other is whether there are any barriers or obstacles to free fish passage - and there are usually plenty! But 'Should I migrate or not?'  is an interesting one that does not get asked very often. Luckily I know someone who does ask such questions! With great pleasure, I hand over to Kim Birnie-Gauvin from the National Institute for Aquatic Resources at the Technical University of Denmark who is conducting her PhD research within the AMBER project.

Physiology & partial migration: from the free radical theory of ageing to residancy and migration in brown trout....

Where in the sea are sea trout?

Posted on December 11, 2017

Where in the sea are sea trout?

As anglers, we often struggle to find fish in a stream, river or lake / loch, and we're generally seeking the bigger fish! Keeping track of the vulnerable juvenile life-stages is even more tricky, and then imagine translocating that problem to the sea.... OK, so with advances in acoustic telemetry, the boffins have a few tricks up their sleeves and are making some headway but the logistics of tracking in such a potentially vast environment are nonetheless challenging. Isabel Moore from the Scottish Centre for Ecology & The Natural Enviornment has risen to that challenge during her PhD and outlines one aspect below.

The brown trout is a remarkably diverse species; it can utilise multiple life-history strategies, ranging from freshwater residency through to migration into marine environments for a period of time before returning to freshwater to reproduce (i.e. anadromous sea trout). Unfortunately, this iconic species has been faced with significant population declines in recent decades across the UK and other parts of the world. A significant portion of the anadromous population decline is thought to occur in marine environments. However, the sheer areal extent of habitats utilised by sea trout makes the monitoring of their movements very difficult, leaving many unanswered questions about the types of challenges that sea trout face and how those challenges might affect the their survival rates. Both environmental (i.e. predation, climate change, etc.) and anthropogenic influences (i.e. overfishing, aquaculture, etc.) have been identified as potential sources of increased mortality, but further research is required to determine the effect of each on wild sea trout.

Resident brown trout (left) and anadromous sea trout with acoustic tag on the rule below (right)

How do chalk stream fish respond to flow and habitat restoration?

Posted on October 04, 2017

How do chalk stream fish respond to flow and habitat restoration?

At the WTT Annual Get Together earlier this year, I had the pleasure of bumping into a former MSc student of mine, Simon Whitton, who now works at Affinity Water and is collaborating with colleagues at Cranfield University, supervising PhD students of his own; a perfect opportunity for another guest blog or four! Since abstraction and chalk streams have hit the headlines repeatedly and this year especially, we should follow Mickaël's progress with interest (and that of Jess Picken too)....

Chalk streams are highly important ecosystems and are a fundamental component of the landscape in the south and east of England. They are hotspots of ecological diversity and support important fisheries for trout and dace amongst others. However, the water that feeds chalk streams originates from groundwater, which is under increasing pressure from abstraction to supply our expanding urban populations. This conflict puts chalk streams squarely in the sights of environmental regulators and water companies as they try to find the best ways to preserve the ecology and the water supply. Hence, my project is sponsored by Affinity Water, and the Environment Agency, and is a part of Cranfield University’s Industrial Partnership PhD studentship programme.

Genetics to underpin effective management

Posted on August 30, 2017

Genetics to underpin effective management

As WTT Conservation Officers, we are asked to make assessments on what is good and bad habitat for trout populations based upon visual observation and expert judgement; this is the basis of a typical Advisory Visit Report. If we had the time and resource, we'd look to the fish themselves to tell us! In this latest blog from current researchers, Jess Fordyce from the University of Glasgow Scottish Centre for Ecology and the Natural Environment outlines how an understanding of the genetic diversity within a catchment can inform more efficient management strategies for safe-gaurding trout populations.

The brown trout, Salmo trutta, is an extremely diverse species in terms of behaviour, physiology, genetics and morphology. Brown trout can adopt a range of life-history strategies which include freshwater residency in rivers and/or lakes, or anadromy – the movement from fresh to saltwater and back again (ie sea trout). The diversity of brown trout in terms of genetics and morphology was the focus of my PhD which was funded by an EU project called IBIS (Integrated Aquatic Resource Management Between Ireland, Northern Ireland and Scotland) and the Atlantic Salmon Trust. My study site was the Foyle catchment which is a large dendritic (branching) system with an area of around 4500km2 located in both Ireland and Northern Ireland. This catchment is managed by the Loughs Agency. Like other catchments across Britain and Ireland, sea trout numbers have been sharply declining over the last few decades. Therefore, it is important to understand the genetic population structuring of brown trout (the pattern of genetic variation) and which environmental factors shape such structuring. From this information, it is possible to detect exactly which populations contribute significantly to the production of sea trout and hence provide focused management.

Tags under trees tell a tale

Posted on August 07, 2017

Tags under trees tell a tale

In science, new questions are always arising from serendipitous discoveries. Angus Lothian tells us of some interesting data on fish predation that has come to light as a part of his PhD project at Durham University, assessing trout behaviour at fish passes.

Every year, Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) undertake an upstream migration in autumn. People watch these fish ‘heavy-weights’ leap, or at least attempt to, over barriers after having already completed maybe tens of miles on their journey to and from sea. Such a migration allows the fish to use rich marine feeding areas to grow larger than they might achieve by staying in freshwater, thus increasing their fecundity or egg production for when they return to their natal rivers. But there are trade-offs. The migration between freshwater and saltwater is filled with risk, resulting in large annual mortality affecting fish populations. For example, for my MRes, I studied the emigration of salmon smolts from rivers, and their behaviour strongly reflected predator avoidance tactics.

Low flows and salmonid rivers: an update

Posted on July 14, 2017

Low flows and salmonid rivers: an update

Jess Picken was the first to contribute to our new series of guest blogs in which she outlined plans for her PhD. And clearly, she has been busy! She is back with an update already...

To recap on my previous post, numerous studies have reported that low flow reduces the density of salmonids within streams. What is not so well-known is what, or how, other parts of the salmonids’ ecosystem are also affected by low flow. Riverflies and other aquatic macroinvertebrates make up a large proportion of juvenile salmonid diet, which is subsequently reflected in salmonid growth rate, condition and survival. Understanding how the availability of these macroinvertebrates changes with reduced summer flow is important to help conserve fish species of high UK and European importance.

My life at the moment... macroinvertebrates down the microscope!

What makes an apex predator: the ferox trout

Posted on June 05, 2017

What makes an apex predator: the ferox trout

I have to admit, the topic of this research really floats my boat (as you may have noticed from the latest Salmo Science Spot)…. I spent several years trying to convince people that perched at the top of the Loch Ness food web was not an elusive plesiosaur but something much, much more sexy. Ferox! So I’m really pleased that the newly doctored Martin Hughes has taken time out to precis his completed PhD, but it does mean I’ll have to review the WTT ferox pages with his new findings.

The brown trout, Salmo trutta, is an incredibly diverse species. Individuals from the same population can adopt completely different life history strategies, which are often given vernacular names. For example, some S. trutta remain in small freshwater streams their entire lives; these are referred to as resident trout. Others migrate into large rivers or lakes to complete their life cycle and retain the name brown trout, but some that migrate into estuarine waters are referred to as slob trout and others that fully migrate into marine waters before returning to natal streams to spawn are called sea trout. One relatively understudied life history is that of ferox trout. ‘Ferox’ which is Latin for ‘Fierce’ is aptly used for these large piscivorous trout which can grow to large size (14kg UK record) and are exceptionally long lived (23 years oldest UK record- reports of 39 years old in Norway). Their impressive growth potential and life span combined with their rarity and near mythical status only adds to the allure to both anglers and scientists alike.

The riparian invasion: salmonid friend or foe?

Posted on May 23, 2017

The riparian invasion: salmonid friend or foe?

'Tis the season to bash balsam - if you don't know how to, check out the definitive guide from WTT chum, Theo Pike, for guidance! Timely then for a new blog focussing on invasive plants. Alex Seeney from the Centre for River Ecosystem Science (CRESS) at the University of Stirling, is battling with balsam and knotweed from a more academic angle, and below gives an overview of some his research to date. This valuable work is supported by Scottish Natural Heritage.

Some of the most diverse and complex habitat types in aquatic systems are found at the interface between terrestrial and aquatic communities – the riparian zone. These diverse, dynamic systems provide an ecologically important buffer between land and water, and as such they are of particular importance to the health and quality of the waterways they border.