WTT Blog - Tagged with catchment management

A WTT advisory visit in 2016 on behalf of Birdsgrove Fly Fishing Club (BFFC) to the River Dove, Derbyshire, identified seven weirs along the 5km length of river fished by the club. The impoundment of water by these structures is detrimental to river habitat, fly and fish populations,especially from a fish passage persepctive, and natural sediment transport. The advisory visit report stimulated a debate within the club about what could be done to improve the fishery and it was decided to work towards the removal of the two weirs that had been built by the club in the past.

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.

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.

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.

Anyone who knows anything about fish in the UK will surely know Dr Martyn Lucas, the head of the Aquatic Animal Ecology Research Group within the School of Biological and Biomedical Sciences at Durham University. He’s an absolute legend and all round good bloke with whom I have done some research in the past. From amongst the many projects he is involved with, his group has published two papers this year revolving around fish passage issues. The first was led by Mike Forty (supported by the Catchment Restoration Fund, CRF) who wrote a layman’s version for us in Salmo and whom I have written about before on the WTT blog pages. Below is a quick summary by Martyn, reproduced with his permission, regarding the second output which included brown trout and bullhead as the study species.  

Jeroen Tummer’s paper concerns longitudinal connectivity restoration for stream fish communities, particularly in terms of the use of ‘nature-like’ passage solutions and obstacle removal, and the utility of a more holistic approach for evaluating outcomes. One of the key findings of our study is that quantitative fish surveys don't do a very good job in telling us whether connectivity restoration work for stream fishes has worked or not in the short term! There are much better ways of doing this as illustrated in the paper. However, they do provide valuable, contextual evidence about changes in the fish community towards or away from the restoration objectives, including those in the longer term (so long as standardised monitoring at a regular frequency is continued).

On my WTT-inspired ramblings recently, I came across a shocking sight, above. Shocking because firstly, I was expecting to see a village pond complete with a raft of local ducks bobbing around, not a barren mudscape stuck behind a defunct dam; and secondly, because I immediately started to wonder where all that accrued sediment was being washed away to….. and where it was being deposited… and might it not be being dumped upon some salmonid redds at a rather inopportune time?

This is the view from my office window. Of late, I have been lucky to see across the valley. When it has been sufficiently clear there has been a stark message staring me in the face. So, what’s wrong in this image? OK, it’s not a great image but then it was taken in blowing rain. The field (centre shot) has a similar slope / exposure as those surrounding it yet it is the only one veined with rivulets of water. It is also the only one under permanent livestock grazing as compared to the fields on either side through which stock is rotated regularly. The result is a reduced crop plant height, root structure (and probably diversity), and more compacted soils leading to serious (visible) overland flow during times of heavy rain. At the bottom of that field is a tributary of the River Aire; little wonder that the Aire is often occupying the full width of its floodplain (below).