‘Citizen science’ on the Lark is saving a precious river species

Two intrepid anglers, who, over the past decade have been battling against all odds to restore the once prized River Lark in Suffolk are doing just this in an effort to add the final pieces to a long and arduous journey of recovery.

Translocating nine million Blue winged olive eggs, Serratella Ignita, and transporting them 400 miles in a round trip, does not sound like a job for the faint-hearted.  But two intrepid anglers, who, over the past decade have been battling against all odds to restore the once prized River Lark in Suffolk are doing just this in an effort to add the final pieces to a long and arduous journey of recovery.

According to Salmon & Trout Conservation UK, the loss of blue winged olives and other important aquatic invertebrate species are an increasing problem on many rivers and chalkstreams because of increasing pollution problems. Their loss or presence is a clear indication of how a river is fairing. Basically lose your invertebrates and many other species will be lost too as they play a crucial role in the food chain for fish and other wildlife.

But the loss of blue winged olives on the River Lark is just part of the tale of woe faced by this once prized chalkstream. However, after years of concerted effort by the Bury St Edmunds Trout Club and the Lark Angling Preservation Society (LAPS), the River Lark is turning the corner from decline to recovery and the results are being captured in the ground breaking Salmon & Trout Conservation UK’s national Riverfly Census.

Ian Hawkins, the Hon Fishery Officer  for Bury St Edmunds Trout Club is passionate about the River Lark and the restoration work by Ian, Glenn Smithson and other members of the two clubs over the past decade is a testament to their dogged determination to succeed, despite the fact that mostly it was considered an impossible task.

The result of this volunteer-led endeavour has been the transformation of a straight, dredged channel, which was converted into a canal in the 19th Century, into a sinuous, lively river bustling with wildlife.  The river now boasts a wild and self-sustaining population of brown trout as well as benefiting all wildlife including damselflies, ground nesting birds, kingfishers, owls and water voles.

Another important result of this restoration project is that it is being included in Salmon & Trout Conservation UK’s (S&TC UK) Riverfly Census, which scientifically monitors the rise and fall of rivers across the UK through measuring the loss or increase of river invertebrates. These important aquatic invertebrates are crucial in identifying the health of a river and their loss is a clear indication of different pollution stresses on a river.

Paul Knight, Chief executive of Salmon & Trout Conservation UK said, “This is a wonderful example of what can be achieved by ‘citizen science’.  Ian Hawkins, Glen Smithson and many others have devoted huge amounts of time and effort into restoring the River Lark, including attending our special River Invertebrate identification course, making them qualified to add important scientific data to our Riverfly Census.  Our 2015 Census results, reported earlier this year, have highlighted that many of our iconic rivers are suffering from serious pollution problems because of human pressure from a variety of sources.  However, the River Lark project sheds a beacon of light and demonstrates that individual groups can really make a difference.  The volunteers on the Lark should be congratulated for their relentless determination to succeed against all odds.”

The Blue winged olive was one of the species that were lost during a pollution event in 2011 which saw the leakage of 5,000 gallons of oil into the river. 

Ian Hawkins said, “Blue-winged olives are an important part of the aquatic food chain and we wanted to put them back.  Following the creation of good habitats, we received a special licence through Natural England for this re-introduction and will be following IUCN guidelines for Translocation of a Species.  We were delighted that Dr Cyril Bennet and Salisbury and District Angling Club on their section of the River Avon and Mr Peter Nash and the Chisenbury Syndicate collected 9 million eggs for us. These will be kept in special conditions until March when they will be released into the river and will hopefully trigger the birth of a new generation of BWO on the River Lark in July/August next year.  This will really be the icing on the cake.”

Ian Hawkins, pays tribute to part of the early work that was carried out by the late Dr Nigel Holmes.  He said, “In 2013 the late Dr Nigel Holmes carried out a fantastic "dig & dump" project with the gravel bed, altering the geomorphology of the river so that it would be self-maintaining and would begin to "heal itself" with new pool and riffle sequences, gravel berms to narrow it and speed up flow and clean away the silt accumulated over many years through over widening and dredging, not to mention the canalisation of the 18th and 19th centuries.  We are currently trying to raise funding to introduce several hundred tonnes of gravels to complete the last works on our Club section.”

Ian continues, “We have ensured the sympathetic planting of the river with a wide range of native water marginal species sought for their added colour and nectar provision to attract insects especially for the Damsels and Dragonfly for which the area is an SSSI. It is only now that this work is showing an amazing improvement in the river and silt is being cleared to allow the gravel bed to be visible for the first time probably in hundreds of years.”