The Tyne Pearl Mussel Project - Freshwater Biological Association

The Tyne Pearl Mussel 

Project 

Marie-Pierre Gosselin, Louise Lavictoire and Roger 

Sweeting 

Wednesday 25 January - Rochester Village Hall, Redesdale

The Freshwater Biological 

Association – Introduction 

• 2 sites: Windermere and 

Dorset 

• Identification courses 

• Scientific publications 

• Pearl Mussel Ark project 

• Captive breeding 

programme 

• Research on host 

specificity of the 

freshwater pearl mussel.

The Tyne Pearl Mussel Project 

• October 2010 – December 2012 

• Based at FBA; funded by FBA, the Environment 

Agency and Northumbrian Water. 

• Two aims: 

1. Identify the factors responsible for the 

decline of the freshwater pearl mussel in the 

North Tyne catchment. 

2. Design a robust, evidence-based restoration 

plan for the species in the North Tyne and 

Rede

Introduction-Freshwater pearl 

mussel ecology and life cycle 

. Lives up to 120 years 

. Complex, peculiar life cycle 

. Parasitic larval stage on 

salmonid host

Habitat requirements of the 

freshwater pearl mussel 

• Well oxygenated water 

• Low calcium concentration 

• Oligotrophic rivers 

• Location of pearl mussel 

beds usually downstream 

of riffles 

• Ideal substrate: mix of fine 

gravel with larger cobble 

and boulder. 

Gail Butterill

The North Tyne catchment 

* Map courtesy of the Tyne Rivers Trust

The River Rede 

• Main tributary of the river North Tyne 

• 58 Km long 

• Geology of carboniferous sandstones with shales covered by 

clay and peat. 

• Regulated by Catcleugh Reservoir in its upper reaches (1905) 

with a minimum compensation flow of 0.158 m 3 s -1 at all times. 

• Rede = 33% of entire volume of water in North Tyne 

• Water quality status “good” according to Water Framework 

Directive 

• Variety of fish species: brown trout, Atlantic salmon, eel, 

lamprey, bullhead, stone loach. 

• Vast salmonid stocking programme: e.g. 2010: 166,791 young 

Atlantic salmon stocked in the Rede ONLY (around 0.5fish/m 2 )

The River Rede – fish diversity 

• Brown trout 

• Eel 

• Brook lamprey 

• Bullhead 

• Atlantic salmon 

• Stone loach 

www.krisweb.com 

davekilbeyphotography.co.uk

Land use in the catchment 

Land use 

North 

Tyne 

Grassland 57 82 

Forestry/ 

woodland 

37 17 

Arable farmland 4 0 

Urban 0 0 

Water 2 2 

Semi-natural 0 0 

Rede 

Total 100% 100% 

Land 

ownership 

North Tyne 

Private 67 64 

MoD 0 20 

Forestry 

Commission 

Northumbrian 

Water 

30 15 

3 1 

Rede 

Total 100% 100% 

58 discharge consents registered 

(Environment Agency). Mostly 

“secondary treated sewage to river” 

and “septic tanks to river”.

Following the Rede...

The freshwater pearl mussel in the 

North Tyne catchment 

• Distribution currently limited to the Rede 

and the North Tyne downstream of its 

confluence with the Rede. 

• Estimated population: around 50,000 

individuals on both rivers (2006 survey) 

• Largest beds: Hindhaigh (499) and 

Townhead (286) in 2006. 

• Most mussels are 50 to 80 years old 

and young mussels are rare. 

• No apparent recruitment 

• Host fish historically believed to be 

Atlantic salmon (Salmo salar). No 

success from the release of artificially 

infected juvenile fish 

Kielder 

North Tyne 

South Tyne 

River Rede 

Tyne

So what‟s going wrong? 

• Impacted flow regime (Kielder releases) 

on the North Tyne? 

• Changes in land use? 

• Pollution? 

• Organic enrichment, eutrophication? 

• Suspended sediments? 

• Siltation and clogging of substrate? 

• Host fish density? 

• Pearl fishing? 

• Most mussels are over 80 and young mussels 

are rare so it is likely that the factors responsible 

for the decline are not recent !

Water Quality Monitoring 

• Monthly monitoring by the Environment Agency 

- on the North Tyne since 1976 

- on the Rede since 1990 

• Monitoring sites at Cottonshope Foot, Otterburn (1990 to 

present) and Redesmouth (1991-2006) 

• Parameters recorded included suspended solids, nitrate, ammonia, 

dissolved oxygen, orthophosphates, pH and some heavy 

metals. 

• Problems: - monitoring not frequent enough 

- no standardisation on the river and across the 

catchment 

- no measurements of pesticides levels 

- no measurements of suspended sediments, turbidity

Water quality and species 

requirements-1 

Biological Oxygen Demand



• Suspended solids at Otterburn



• Nitrate



• Phosphate

Water quality monitoring July ‟11 – 

January „12 

• Turbidity

Conclusions from water quality 

data analysis 

• Enrichment and increase 

in fine sediments appear to 

be responsible for pearl 

mussel decline in the 

North Tyne and Rede 

• Fine sediments from 

erosion and runoff 

• Enrichment probably as a 

result of agriculture and 

other human activities.

Causes of sediment input/siltation 

• Poaching by livestock 

• Dredging of the river 

channel 

• Topography of the 

catchment 

• Drainage on arable land 

• Forestry activities

Causes of nutrient enrichment in 

water 

• Agriculture 

(fertilizers, drainage, 

manure) 

• Wastewater 

• Untreated sewage

Example of a semi-natural system 

www.ecan.govt.nz

Other work and findings 

• Host fish preference: 

Atlantic salmon/brown trout 

• Fieldwork: characterisation 

of physical habitat across 

the catchment

What we can do to help the pearl 

mussel. 

HABITAT ACTIONS 

• Implement a more comprehensive water 

quality monitoring programme 

• Limit sediment input in the river 

• Prevent nutrient input in the water 

• Clean gravels: desilting 

PEARL MUSSEL ACTIONS 

• Captive breeding programme for adult 

relocations 

• Release of infected fish in the river

Examples of habitat restoration 

Forestry.gov.uk 

Tyne Rivers Trust 

Defra.gov.uk

HE 

REDE PEARL 

MUSSELS NEED 

YOU!!!

The Tyne Pearl Mussel Project - Freshwater Biological Association

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