WTT Blog

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!

By Rob Mungovan, WTT Conservation Officer for East Anglia and Central Region

As a new starter my colleagues have been interested to know what projects I’ve already delivered whilst working as a local authority ecologist. I’m able to explain all the usual techniques of channel narrowing and bed raising but one novel approach keeps getting more questions. So the clearest way to explain it is to write it down, and include some pictures. The one below hows the restored brook. 

The restored (or re-built?) brook. The new bed is suspended over soft silt through the use of grass mesh.

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.

'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.

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. 

Jeroen Tummers has been wrestling with more holistic fish passage solutions during the course of his PhD with Dr Martyn Lucas at Durham University (Martyn gave us a few comments about this project on a previous WTT Blog). But below, we hear from Jeroen himself, about his valuable contribution.  

One of the most important components in restoring impacted river systems, given their linear nature, is to reconnect habitat patches separated by obstacles to free movement. Fishes rely on free access to habitat upstream, and downstream, in a river system to spawn, for feeding, or for finding refuge. Since the presence of these three functional habitat types can change both spatially and temporally, it is important that free access is retained.

In the first of a new series from students actively involved in research relevant to wild trout, Jessica Picken from Queen Mary University of London summarises the aims of her PhD working with the Game & Wildlife Conservation Trust and with CEFAS.

Climate change is considered to be the most critical disturbance imposed on natural systems on a global scale. Climate models predict that average temperatures in the UK will increase over the course of the next 50 years with the greatest warming in the south of England during summer months, and that annual average precipitation will reduce. However, the reduction in precipitation is expected to be more pronounced during summer than winter, whereas extreme winter precipitation is expected to become more frequent. In other words, there is likely to be an overall shift towards drier summers but wetter winters.

Fishing and family holidays in 2017 in the WTT auction

Short, grey days and limited fishing opportunity over Christmas and New Year tends to make me think of summer holidays.  As I write the lot descriptions for the WTT’s annual fundraising auction,  especially the ‘fishing overseas’ section,  I can dream about travelling to exotic rivers to fish in warm sunshine.  This year, it occurred to me that many of the ‘overseas’ lots could be combined family holidays, and perhaps some advance notice might be useful to aid planning.