Exploring the Mor Brook

The first river health training session went ahead this month at the diverse and picturesque Mor Brook. The 11 mile long Brook begins its journey south of Much Wenlock and travels south east past Bridgnorth and Eardington to join the Severn near Crateford. The Brook meanders through a variety of land uses including a quarry, agricultural land and woodland. Although it was a very cold day, the team and enthusiastic bunch got stuck in and learnt a technique called kick sampling. This technique is used to collect a representative sample of invertebrates as they are key indicators to river health due to different species being more tolerant to pollution than others. The group found a mixture of invertebrates including damselfly larvae, burrowing mayfly, swimming mayfly, freshwater shrimp and case cadis all of which are a good indication of a healthy river. Further to that, a chemical test of the water was taken which showed normal levels of the chemical parameters we would expect in rivers. For example nitrate levels were below 0.25mg/l (milligrams per litre) in contrast to 10mg/l standard level of nitrate in drinking water. Therefore, showing low levels of nitrate within the water and a overall healthy river.

Spawning

Winter has arrived and spawning for Trout and Salmon has begun! Spawning beds otherwise know as spawning redds are vital for these fish to produce the next successful generation of strong healthy fish.  Redds can be found scattered throughout the river system especially in shallow riffly water, close to the surface, to provide the right oxygen levels for the eggs to survive. The riverbed must also have the right sized gravel for a female fish to clean and shape into an oval nest, usually 1-3 feet wide. The female will then lay her eggs which  the male fertilizes. The eggs will  develop throughout winter and by the 97th day they will hatch.

Spawning redds are located close to river banks and shores making them vulnerable to a range of pressures such as human activity, traffic, launching of canoes and severer weather events. All these factors have the potential to dislodge gravel and expose the eggs to predators or destroy them completely. Redds are positioned so that downstream flow forces water through the gravel and across the buried eggs. This brings oxygen to the eggs and alevins (newly spawned salmon or trout) while moving waste products away from the eggs. However, excessive amounts of silt traveling downstream due to disturbance upstream can latch on to the eggs and deprive them from oxygen leading to the eggs unsuccessfully hatching.

Harvesting, with a difference

by Alex Grant

As I look out of my window at the grey mizzling sky, the warm weather of the summer and early autumn is already but a distant memory.  It seems to take more effort to dress up and go out into the cold damp air to pedal my bike or paddle my canoe.

Most of the farmers’ harvests have been gathered in, and the fields have been cultivated and sown with next year’s crops.  The first flocks of winter visitors, such as fieldfares and redwings, are passing through and they have been busy harvesting the red berries from the hawthorn bushes along our canals and roads.

I too have been gathering a harvest, but not of any natural produce.  As the vegetation has died back along the edges of the water, the annual accumulations of litter discarded by boaters and other users of the canal have become exposed.  In the past fortnight alone, I have collected and disposed of about 80 items comprising single-use bottles, cans, bags, wrappers, polystyrene foam and other plastics. 

Unsightly this is of course but, following the graphic footage at the end of David Attenborough’s “Blue Planet” series, who can be unaware now of the huge rafts of degrading plastic waste circulating far off-shore in the middle of the major oceans.  And we are beginning to appreciate that this has massive implications throughout the entire food chain.

As I learnt during Shropshire Wildlife Trust’s clean-up this year on the River Severn, in the course of which we collected 5,000 items of litter and other discarded materials, it is estimated that some 80% of all the plastic in the oceans has originated in rivers and other water-courses.  It behoves us all to minimise and eventually eliminate this impact.

Upcoming dates

· 5th Dec World Soil Day - International Volunteer Day

River health training day events

· Tuesday 18th December at 10am—12pm. Meeting at the River Clun, Craven Arms. Please park on the carpark opposite Bridge Coffee Shop (SY7 8JW) by The Old Bridge. Facilities available and  welcome to everyone.

· Friday 18th Jan 2019 at 10am—12pm. Meeting at Carding Mill Valley, Church Stretton. Lower stretch of Carding Mill Valley. Parking at National Trust car park for Carding Mill.

· Monday 18th Feb 2019 at 10am—12pm. Meeting at River Perry, Gobowen. Located on a stretch of River Perry adjacent to the playing field of the       Village Hall on St Martins Road.  Parking Available at Village Hall car park on St Martins Road.

· Monday 18th Mar 2019 at 10am – 12pm. Meeting at Cantern Brook, Bridgnorth. Located on a Stretch of Cantern Brook adjacent Dingle View, WV16 4JL. Suggested parking: Dingle View.