From the Stanley Picker Island at Kingston University’s Middle Mill campus you can see a strange looking device attached to the river’s tall concrete wall. This is an eel pass with a specially designed integrated eel monitoring trap. Part of a wider Zoological Society London (ZSL) project, this trap is monitored by Kingston University volunteers.

ZSL are monitoring eels at several Thames sites, and at lots of tributary sites too – one of which is this Hogsmill trap. The valuable data generated by traps such as this one has been utilised by the Environment Agency and the International Council for the Exploration for the Sea (ICES) to inform management initiatives. The study has also increased ZSL’s knowledge of the species in the Thames catchment and raised awareness of the declining eel populations.

The Kingston University volunteers at the Hogsmill eel trap include students, members of staff and local residents. To check the trap they don a pair of waders and a buoyancy aid - the river is only about a foot deep, but we like our volunteers and want to keep them safe! There is always two volunteers on site – one to go into the river to check the trap, and one to stay on the bank overseeing the action.

If an eel is found in the trap, it is carefully extracted and measured by the volunteers before being released upstream of the trap and weir. Data is promptly fed back to ZSL via their website, where it is put to good use by their fisheries scientists and ecologists.

Directions
Exit the campus through the black gate on your right. Turn immediately left, following the public footpath alongside the Hogsmill River until you reach the two bridges.

There are a number of aquatic birds that can be spotted from the banks of the Hogsmill River. Knight’s Park is an ideal area to do a bit of bird spotting.

What you could see:

Grey Wagtail (Motacilla cinerea)

These birds can often be spotted around the Knights Park area of the Hogsmill. They favour flowing water, which has plenty of exposed rocks, so you can see why they like it here! You can spot them by their bright yellow belly, undulating flight and wagging tail. Interesting fact: Grey Wagtail are highly territorial, both when they are feeding, and when they are breeding and nesting.

Coot and Moorhen (Fulica atra and Gallinula chloropus)

These birds belong to the Rallidae family. Coot have white beaks, and Moorhen have red and yellow beaks. They are aquatic birds which can almost always be spotted at this point on the Hogsmill – in the Spring you can even see Coot nests, sometimes in mid-stream.

Grey Heron (Ardea cinerea)

Sometimes you will spot a heron standing dead still in the shallow waters of the Hogsmill in this area. It is probably fishing – waiting patiently for its prey to swim by, before snatching it out of the water.

Interesting fact: Grey Heron are large birds – the average wingspan is 6ft.

Mallard (Anas platyrhynchos)

The most recognisable wildfowl, this dabbling duck (family: Anatini) can commonly be spotted on ponds, lakes, rivers and streams. You will sometimes see Mallard nesting along this stretch of the Hogsmill in the Spring.

Interesting fact: A Mallard doesn't feed her brood, as they are capable of finding their own food as soon as they leave the nest.

Directions
Done with bird watching? Follow the signposted Hogsmill Valley path alongside the southern bank of the Hogsmill. Upon reaching the end, cross the Blue Bridge and take the first left (Grange Road). After approximately 2 minutes, take a left hand turn into the signposted narrow footpath.

Can you see the strange white plastic box, which runs over the weir on the opposite side of the river? That is an eel ladder! It is designed to help eels to climb over the weir as they have an incredible urge to swim up steam and live a cosy life in small rivers such as this one.

Directions
Continue across the bridge, and take an immediate right hand turn, following the winding footpath until you reach the main road (Penrhyn Road). Cross at the Toucan crossing and bear right towards the roundabout. Take the first left hand turn at the roundabout, and cross at the first crossing you see. You will hear, and probably see the river straight in front of you - head towards it, and follow the footpath that runs alongside it. Note the way in which the Hogsmill has been integrated into the urbanisation of this area - in some places it runs beneath the road and buildings.

This pathway which passes alongside the RBK Guildhall complex is a great place to watch the fish in the Hogsmill River. The river here has been widened, and is very shallow, so you can easily spot the river fish which hang around here waiting for some dinner. What you could spot:

European Chub (Squalius cephalus)

These bright silver freshwater fish can be easily spotted in the Hogsmill. It can be found in slow to medium flowing rivers, canals and even lakes.

Interesting fact: The European Chub can live for up to 15 years.

Common Dace (Leuciscus leuciscus)

Dace can be found in both fresh and brackish (slightly salty) waters. They feed mainly on insects and insect larvae. Often seen in shoals, it favours faster flowing water.

Interesting fact: The Dace is a relatively small fish which is often preyed upon by larger fish.

European Eel (Anguilla anguilla)

The European Eel has a truly strange life-cycle. After spawning in the Sargasso Sea (in the Middle of the North Atlantic Ocean), the tiny eel larvae (leptocephali) travel on the North Atlantic Ocean currents to Europe and North Africa. Upon entering river estuaries, including the Thames, they transform into tiny see-through glass eels. The eels live in these rivers and their tributaries for most of their lives, going through several further transformations - from glass eels to elvers, to yellow eels to silver eels. After living in these rivers for up to 20 years, they make the 4000 mile journey back to the Sargasso Sea where they spawn and die, completing their life cycle.

Interesting fact:The European Eel is classed as critically endangered. Possible reasons for its decline in recruitment include: barriers to migration (weirs, dams), climate change (changing ocean currents) and overfishing.

Mitten Crab (Eriocheir sinensis)

Also known as the Chinese Mitten Crab and the Shanghai Hairy Crab, this crab is an invasive species which is native to eastern Asia. It arrived in Europe nearly 100 years ago, probably via ships which had taken on water as ballast to stabilise them. The Mitten Crab causes problems in the rivers of Europe because it is thought to burrow into riverbanks, leading to their collapse.

Interesting fact: The mitten crab actually has mittens – a furry covering – on its claws. Its scientific name Eriocheir sinensis, derived from Greek, means "wool hand, the Chinese".

Directions
Continue along the footpath until you emerge onto High Street. Cross the road at the Zebra crossing which sits on the Clattern Bridge, and slip through the small gateway to the right of the bridge. From here you can walk alongside the Hogsmill River until you reach its confluence with the Thames.

This artificial wetland area was created alongside the Charter Quay on the edge of the River Thames and Hogsmill Creek and is a valuable ecological site in the centre of Kingston. Many insects can be found, small waterfowl feed and nest here and fish spawn in the quit backwater.

The overall aim for the area is for natural regeneration of riverside plant species so that the vegetation slowly establishes as a wild riverbank planting. Minimum human intervention will ensure that vigorous species such as bindweed are kept under control and the more special plants such as hemlock water dropwort and phragmites reeds are encouraged to increase the diversity of riverbank species. The metal cages protect the roots and tender young shoots of native plants from grazing geese, ducks and swans, which helps to prevent erosion.

Patches of nettles provide food for a number of butterfly caterpillars, including the common white, red admiral, painted lady, peacock, comma and small tortoiseshell. The willow trees are also very important as they are know to host up to 250 species of invertebrates.

Plant species growing here include: Sedges, greater water parsnip, sweet rush, water mint, flag iris, creeping Jenny, common reed, angelica, mugwort, hemlock water dropwort, betony, dock, nettle and bindweed. Visiting waterfowl include – cormorants, swans, Canada geese, moorhens and coots.

Directions
Exit the campus through the black gate on your right. Turn immediately left, following the public footpath alongside the Hogsmill River until you reach the two bridges.