Sizes, densities and age structures of Scottish Margaritifera margaritifera (L.) populations

L C Hastie, M R Young, P J Boon, P J Cosgrove, B Henninger

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

1. Populations of freshwater pearl mussels (Margaritifera margaritifera (L.)) were surveyed in 12 Scottish rivers (selected from those known to contain viable populations). Overall mussel densities in different rivers ranged from 0.27 to 30.01 m(-2) Median densities ranged from 2.5 to 14.5 m(-2) and a maximum of 398 mussels m(-2) was observed in one river.

2. Total population estimates in different rivers ranged from 2000 to 0.9-3.7 million. One population is particularly dense, with an estimated 0.6-1.2 million mussels in a 4-km stretch of river.

3. Samples from nine populations were taken in order to provide mussel size/age data. Marked differences between size profiles and their corresponding age profiles were observed. It is difficult to interpret the former in terms of recruitment.

4. There were signs of recent recruitment in all of the populations investigated. Large numbers of young mussels (aged less than or equal to 20 years) were found in four rivers. The largest proportions at any particular site were 67/219 (30.6%) aged less than or equal to 10 years and 191/219 (87.2%) aged less than or equal to 20 years, both values being recorded in the same river.

5. The expected predominance of young mussels was not achieved in any population. Presumably, there is considerable underestimation of the youngest age classes owing to biased sampling techniques. However, several populations are thought to be recruiting at levels that are high enough to maintain viability.

6. One population (River F) is the best example of a 'healthy', moderately fished, recruiting population and its age profile could be used as a benchmark for future comparisons.

7. The results of this study emphasize the international importance of Scotland in terms of M. margaritifera conservation. However, the small numbers of juveniles found in some Scottish rivers indicates that many populations are vulnerable to decline and, therefore, their conservation status may be threatened in the long term. Copyright (C) 2000 John Wiley & Sons, Ltd.

Original languageEnglish
Pages (from-to)229-247
Number of pages19
JournalAquatic Conservation: Marine and Freshwater Ecosystems
Volume10
Publication statusPublished - 2000

Keywords

  • freshwater pearl mussel
  • conservation
  • population density
  • age profile
  • WATER PEARL MUSSEL
  • FRESH-WATER
  • CONSERVATION
  • EUROPE
  • SOUTH

Cite this

Hastie, L. C., Young, M. R., Boon, P. J., Cosgrove, P. J., & Henninger, B. (2000). Sizes, densities and age structures of Scottish Margaritifera margaritifera (L.) populations. Aquatic Conservation: Marine and Freshwater Ecosystems, 10, 229-247.

Sizes, densities and age structures of Scottish Margaritifera margaritifera (L.) populations. / Hastie, L C ; Young, M R ; Boon, P J ; Cosgrove, P J ; Henninger, B .

In: Aquatic Conservation: Marine and Freshwater Ecosystems, Vol. 10, 2000, p. 229-247.

Research output: Contribution to journalArticle

Hastie, L C ; Young, M R ; Boon, P J ; Cosgrove, P J ; Henninger, B . / Sizes, densities and age structures of Scottish Margaritifera margaritifera (L.) populations. In: Aquatic Conservation: Marine and Freshwater Ecosystems. 2000 ; Vol. 10. pp. 229-247.
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TY - JOUR

T1 - Sizes, densities and age structures of Scottish Margaritifera margaritifera (L.) populations

AU - Hastie, L C

AU - Young, M R

AU - Boon, P J

AU - Cosgrove, P J

AU - Henninger, B

PY - 2000

Y1 - 2000

N2 - 1. Populations of freshwater pearl mussels (Margaritifera margaritifera (L.)) were surveyed in 12 Scottish rivers (selected from those known to contain viable populations). Overall mussel densities in different rivers ranged from 0.27 to 30.01 m(-2) Median densities ranged from 2.5 to 14.5 m(-2) and a maximum of 398 mussels m(-2) was observed in one river.2. Total population estimates in different rivers ranged from 2000 to 0.9-3.7 million. One population is particularly dense, with an estimated 0.6-1.2 million mussels in a 4-km stretch of river.3. Samples from nine populations were taken in order to provide mussel size/age data. Marked differences between size profiles and their corresponding age profiles were observed. It is difficult to interpret the former in terms of recruitment.4. There were signs of recent recruitment in all of the populations investigated. Large numbers of young mussels (aged less than or equal to 20 years) were found in four rivers. The largest proportions at any particular site were 67/219 (30.6%) aged less than or equal to 10 years and 191/219 (87.2%) aged less than or equal to 20 years, both values being recorded in the same river.5. The expected predominance of young mussels was not achieved in any population. Presumably, there is considerable underestimation of the youngest age classes owing to biased sampling techniques. However, several populations are thought to be recruiting at levels that are high enough to maintain viability.6. One population (River F) is the best example of a 'healthy', moderately fished, recruiting population and its age profile could be used as a benchmark for future comparisons.7. The results of this study emphasize the international importance of Scotland in terms of M. margaritifera conservation. However, the small numbers of juveniles found in some Scottish rivers indicates that many populations are vulnerable to decline and, therefore, their conservation status may be threatened in the long term. Copyright (C) 2000 John Wiley & Sons, Ltd.

AB - 1. Populations of freshwater pearl mussels (Margaritifera margaritifera (L.)) were surveyed in 12 Scottish rivers (selected from those known to contain viable populations). Overall mussel densities in different rivers ranged from 0.27 to 30.01 m(-2) Median densities ranged from 2.5 to 14.5 m(-2) and a maximum of 398 mussels m(-2) was observed in one river.2. Total population estimates in different rivers ranged from 2000 to 0.9-3.7 million. One population is particularly dense, with an estimated 0.6-1.2 million mussels in a 4-km stretch of river.3. Samples from nine populations were taken in order to provide mussel size/age data. Marked differences between size profiles and their corresponding age profiles were observed. It is difficult to interpret the former in terms of recruitment.4. There were signs of recent recruitment in all of the populations investigated. Large numbers of young mussels (aged less than or equal to 20 years) were found in four rivers. The largest proportions at any particular site were 67/219 (30.6%) aged less than or equal to 10 years and 191/219 (87.2%) aged less than or equal to 20 years, both values being recorded in the same river.5. The expected predominance of young mussels was not achieved in any population. Presumably, there is considerable underestimation of the youngest age classes owing to biased sampling techniques. However, several populations are thought to be recruiting at levels that are high enough to maintain viability.6. One population (River F) is the best example of a 'healthy', moderately fished, recruiting population and its age profile could be used as a benchmark for future comparisons.7. The results of this study emphasize the international importance of Scotland in terms of M. margaritifera conservation. However, the small numbers of juveniles found in some Scottish rivers indicates that many populations are vulnerable to decline and, therefore, their conservation status may be threatened in the long term. Copyright (C) 2000 John Wiley & Sons, Ltd.

KW - freshwater pearl mussel

KW - conservation

KW - population density

KW - age profile

KW - WATER PEARL MUSSEL

KW - FRESH-WATER

KW - CONSERVATION

KW - EUROPE

KW - SOUTH

M3 - Article

VL - 10

SP - 229

EP - 247

JO - Aquatic Conservation: Marine and Freshwater Ecosystems

JF - Aquatic Conservation: Marine and Freshwater Ecosystems

SN - 1052-7613

ER -