WTT Blog - Tagged with research

Plant invasions and trout rations: the sequel

Posted on January 07, 2019

Plant invasions and trout rations: the sequel

It's a great pleasure to welcome back Alex Seeney to the WTT Blog. Just over 18 months ago, he was one of the first of the early career researchers to contribute a post (The riparian invasion: salmonid friend or foe?) about their ongoing science. Well, Alex is now Dr Alex (congratulations) and has returned with an update which I have been eager to see. I well remember some work by Sally Hladyz on how invasive rhododendron can severely impair stream functioning; her work demonstrated that the plant supplied poor leaf litter quality and blocked out the sun, subsequently depressing decomposition rates and algal production rates meaning less food for inverts. Do balsam and knotweed exert similar influences? Over to (Dr) Alex.....

Invasions by non-native species are reported as one of the greatest threats to global biodiversity, and the invasion of riparian ecosystems by invasive non-native plants (INNP hereafter) presents a common and difficult challenge for river and fishery managers.

Connectivity at Coniston Cold

Posted on July 09, 2018

Connectivity at Coniston Cold

And so it comes to pass….Coniston Cold weir, which in various forms has been a man-made obstruction to fish passage on the R Aire in N Yorkshire for the past 180 years at least, is no more. Instead, there is now 20.4km of uninterrupted free passage along the Aire and a major tributary.... and all for less than £8k!

Coniston Cold Weir: 19m wide and 1.2m headloss, with a 4m horizontal block-stone apron

I will not reinvent the wheel and spend time here discussing how weirs cause environmental issues. The evidence is abundant and simple to find in the scientific literature, and my colleague Paul Gaskell has recently summarised much of that, here. Then there are global-local events like World Fish Migration Day to raise awareness and I would wager that almost every conservation body involved with river restoration has a hit-list of target weirs on their local patch.

All about the (sea) trout

Posted on June 14, 2018

All about the (sea) trout

Hopefully a few sea trout have found a bit of water (not round here mind) and are starting to return to our rivers at the moment. Fitting then to hand over the blog to Angus Lothian, a PhD student at Durham University (see his first blog here) to reflect on a new network for sea trout research.

Salmo trutta is a truly fascinating ‘species’, with such varying life history strategies and showing large phenotypic plasticity, exemplified by their key characteristic of partial-migration.  It is not yet fully known what drives partial-migration, with a component of a population of trout smolting and emigrating from rivers to sea, and the rest remaining river-resident.  Although the trout has often played second fiddle to Atlantic salmon, recent surges in the interest of trout ecology and biology, and in particular sea trout, has led to a rise in the number of scientists and PhD students researching this field.

MSc Research with WTT

Posted on May 23, 2018

MSc Research with WTT

I’ve just had the pleasure of hosting two MSc students from Queen Mary University of London (co-supervised with Dr Chris Eizaguirre), partly for the WTT Annual Get Together, and partly to undertake some fieldwork specifically for Charlotte Pike’s project. I alluded to their research projects in a former post and now I have the pleasure of handing over to them to update you.

Charlotte’s project focuses on the use of stable isotopes to determine the success of river restoration. I will be analysing samples from pre and post intervention works against an unimpacted control site on the same river to see how the restoration has affected the ‘architecture’ of the food web. Hopefully it should be more like the control! The intervention works have been carried out by the Ribble Rivers Trust at two locations; Bashall Brook and Towneley Hall. At Bashall Brook, a riparian zone has been created where banks of the river were previously bare; essentially livestock exclusion fencing now removes the impacts of grazing and poaching. This strip of vegetation acts as a buffer to reduce nutrient run-off from farmland, keeps the ground more stable and resilient to flood damage to reduce soil erosion, and provides necessary refuge for wildlife. At Towneley Hall, a partial weir removal and a rock pass re-instates the connectivity of the River Calder allowing fish to move between formerly fragmented habitats. These interventions have been conducted to improve the quality of the habitat at these two sites, and it’s my job to find out what changes have occurred as a result! 

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

Spot the difference(s)

Posted on March 10, 2018

Spot the difference(s)

Gather some fine fishy folk into a room and get them talking (as if you could stop ‘em) about brown trout. How long do you reckon it would be before the topic of colour or more likely spotting pattern would creep in? Let’s face it, we love our spotties! It’s just such an integral part of their beauty and wonderful diversity.

So, for no other reason than the sheer beauty of ‘em, I’m going to ask you good supporters of WTT to snap a few images of wild brown trout spots when you’re out this season but specifically trying to focus on one area – square on and below the dorsal fin. In fact, just like the images scattered around this page, trying to avoid any large patches of glare / reflection / contrast. These images were lifted from 'whole' fish shots, and hence aren't the best quality. I'm hoping you can provide some close ups of the fish flank.

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….

Woodplumpton Brook Restoration: Baffle-ing Results!

Posted on December 18, 2017

Woodplumpton Brook Restoration: Baffle-ing Results!

With my ‘Research’ & Conservation Officer cap on, I can straddle the often hefty divide between academia and NGO/grass roots conservation groups and do a little bit to pull them together. Queen Mary University of London buy out some of my time and expertise from WTT to give their aquatic ecology MSc students practical training and experience in the field. As a part of a week-long fieldcourse based in the Lake District, I have forged a link between them and Wyre Rivers Trust but I’ll let some of the excellent members of this year’s cohort tell you about it, below. Thanks to Dr Christophe Eizaguirre and the rest of the students who worked efficiently on the day to provide the data, and of course, to Tom Myerscough from Wyre RT for sorting out the relevant permissions.

The Wyre is one of the key rivers of Lancashire, with its catchment covering much of the North of the county. It has historically been known as one of the best sea-trout fisheries in England. However, in the post-war 20th Century, like most rivers it suffered from intensified agriculture, urbanisation and new engineering methods, and these changes have cumulatively affected fish communities.

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)

Capturing Catchment Connectivity Issues

Posted on November 13, 2017

Capturing Catchment Connectivity Issues

Here at WTT, we're (no pun intended!) all for reconnecting fragmented systems: see recent news items from Tim Jacklin's work on letting the Dove flow, applications of Mike Blackmore's patented #weirbegone, or some of my recent work with Aire Rivers Trust as just a few examples. Europe wide, indeed globally, there is growing recognition of such issues but do we know even the true extent of the problem? Hence, it's great to hear from Siobhán Atkinson regarding her current PhD research.

River connectivity is vital for sustaining healthy freshwater ecosystems. It is important for maintaining resident as well as migratory fish populations, natural sediment movement, and habitat for macroinvertebrate communities and other aquatic organisms. Despite this, few rivers remain uninterrupted across Europe.

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.

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.

Can watercress farming directly impact fish communities in chalk streams?

Posted on April 27, 2017

Can watercress farming directly impact fish communities in chalk streams?

Asa White gets to call wading around in the Bourne Rivulet work! Our research interests in chalk streams have some parallels. While I am curious as to how a colourless, odourless gas (methane) contributes to the fuelling of their food webs, Asa is trying to understand how an equally invisible chemical is affecting invertebrate and fish life. Here, he outlines his research plans and offers up the experience of electric fishing - read on! 

Watercress is native to the chalk streams of southern England, and has been harvested for millennia. In the early 19th century, the advent of the railway made commercial production viable for the first time. A growing London market supplied by trains (the famous ‘Watercress Line’ being one) led to an explosion in the number of watercress farms throughout the south of England. Historically, watercress was grown in gravel beds irrigated by water diverted from chalk streams, but hygiene concerns now oblige growers to irrigate their beds using fresh water abstracted from boreholes. In both instances, the water used to irrigate the beds is discharged into adjacent chalk streams.