River Ouzel Invertebrates

River Ouzel - Simpson bridge invertebrate species list. Data supplied by the National Rivers Authority.

Biological scores for the assessment of biological quality of rivers based on the recommendations of the Biological Monitoring Working Party (BMWP). Each family has a single score irrespective of the number of individuals or species recorded from that family. Family scores are added up to give a single BMWP value for the site at each sample date. Some individual species are also noted, scores for their family are given in brackets, care must be taken to avoid scoring the individual species AND their family or more than one species from the same family.

At each sample date the abundance is also recorded on the following 5 point scale: 1 = 1, 2-10 = 2, 11-100 = 3, 101-1000 = 4, over 1000 = 5.

Biological score Species Common name 15/6/93 25/10/93 4/5/94 7/10/94
6 Neritidae Snails 1 2 .1
6 Viviparidae Snails . 2 .2
3 Valvatidae Snails . 2 22
(3) Potamopyrgus jenkinsi Jenkins' spire shell 2 3 .2
(3) Bithynia tentaculata Snail 2 2 12
3 Lymnaeidae Snails 2 1 .2
(3) Lymnaea stagnalis Greater pond snail . . 2.
3 Planorbidae Ram's horn snails 2 2 22
6 Unionidae Freshwater mussels . . 21
3 Sphaeriidae Pea mussels 2 2 22
1 Oligochaeta Worms 3 2 22
(4) Piscicola geometra Leech . 1 ..
3 Glossiphoniidae Leechs . 1 .2
(3) Glossiphonia complanata Leech 1 . 3.
(3) Erpobdella octoculata Leech 2 2 21
Not scored Hydracarina Water mites . 3 3.
3 Asellidae Water-lice . . 22
(3) Asellus aquaticus Water-louse 2 3 ..
6 Gammaridae Fresh-water shrimps . . 3.
7 Caenis spp. May-fly (nymphs) 2 3 22
6 Coenagriidae Damsel-fly (nymphs) 2 . 2.
8 Calopterygidae Damsel-fly (nymphs) 1 2 22
5 Hydrometridae Watermeasurers 1 . ..
Veliidae Water crickets 1 . ..
5 Haliplidae small Water beetles . 2 21
5 Dytiscidae Water beetles 1 2 2.
5 Scirtidae Water beetles 1 . ..
5 Elmididae Water beetles . 2 .1
4 Sialidae Alderfly (larvae) . . 2.
4 Sialis lutaria Alderfly (larvae) . . .1
6 Hydroptilidae Caddis-fly (larvae) . . 2.
7 Polycentropodidae Caddis-fly (larvae) . 1 ..
5 Hydropsychidae Caddis-fly (larvae) . 2 22
7 Limnephilidae Caddis-fly (larvae) . . 3.
10 Leptoceridae Caddis-fly (larvae) . 2 32
5 Tipula spp. Crane-fly (larvae) 2 . ..
5 Simuliidae Black-fly (larvae) . . 22
2 Chironomidae Midge (larvae) 2 . 22
Summary
BMWP total 71 93 10788
Average score per taxon (ASPT) 4.2 4.5 4.74.4
Lincoln quality index (LQI) 4.5 5.5 6.05.0

BMWP scores and water quality

A score of less than 25 = poor, 26-50 = moderate, 51-100 = good, 101-150 = very good, more than 150 = exceptional.

Lincoln quality index (LQI)

Similar to BMWP but also takes account of the average per family and habitat quality (either habitat rich or habitat poor, this part of the river Ouzel is classed as habitat poor), the actual value of LQI is based on sets of tables which are not given here.

LQI ratings: 1-1.5(I-H) = very poor, 2-2.5(G-F) = poor, 3-3.5(E-D) = moderate, 4-4.5(C-B) = good, above 5(A, A++) excellent.

River quality objective Minimum LQI required
Salmonid fishery B
Potable water supply direct to treatment, High amenity value C
Potable water supply via impoundment, Cyprinid fishery D
Moderate amenity E
Low amenity G


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