Life history changes in Atlantic salmon from the River Dee, Wales

  • Miran W. AprahamianEmail author
  • Ian C. Davidson
  • Richard J. Cove
Part of the Developments in Hydrobiology book series (DIHY, volume 200)


The change in life history of Atlantic salmon (Salmo salar L) on the River Dee over the last 60 years is described. Over the last 60 years, salmon have shown a change in run timing, the majority currently entering the liver between August and October compared with prior to June. This has coincided with a change in the sea age composition, which was dominated by multi-sea winter salmon prior to the 1980s after which the proportion of 1sea-winter fish increased until they now dominate the mature population. Growth rates of salmon in fresh water remained relatively stable until the mid-1980s and then increased. By the end of the 1990s juvenile salmon were, by the end of their first and second year, respectively, ∼60 and ∼19%, on average, larger than they were between the late 1930s and mid-1980s. This has been reflected in a change in the age composition of smolts where the mean smolt age has declined from ∼2 years prior to the 1980s to ∼1.6 years in the late 1990s. There was no observed trend in post-smolt (marine) growth for salmon. Size at return for 1SW salmon appeared stable while there is some evidence of an increase in mean length of 2SW salmon at the end of the 1990s. A steady state life history model was developed which suggests an increase in the instantaneous rate of mortality by 2.9% from 1.495 year−1 in 1937/1938 to 1.538 year−1 in 1967/1969 and by 21.6% to 1.870 year−1 in 1997/1999. This is considered to explain the shift in mean age at maturity from 5.2 to 4.8 to 3.9 years for the three periods examined. There is close argeement between the observed mean age at maturity and that predicted by the model suggesting optimal lifetime reproductive success.


Salmo salar Life history Sea age Smolt age Growth Run timing 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Alm, G., 1959. Connection between maturity, size, and age in fishes. Report of the Institute of Freshwater Research. Drottningholm 40: 5–145.Google Scholar
  2. Anon., 1994. Run Timing of Salmon. MAFF Publications. London.Google Scholar
  3. Anon., 2006. Annual Assessment of Salmon Stocks and Fisheries in England and Wales 2005. Environment Agency, Bristol; Centre for Environment, Fisheries and Aquaculture Science, Lowestoft.Google Scholar
  4. APEM, 1998. An Investigation into the Impact of Flow Regulation on Fisheries in the River Dee. Environment Agency, Bristol.Google Scholar
  5. Bagliniere, J. L., L. Denais, E. Rivot, J. P. Porcher, E. Prévost, F. Marchand & V. Vauclin, 2004. Length and age structure modifications of the Atlantic salmon (Salmo salar) populations of Brittany and Lower Normandy from 1972 to 2002. Technical report, Institut National de la Recherche Agronomique and Conseil Supérieur de la Péche, Rennes.Google Scholar
  6. Beaumont, W. R. C., J. S. Welton & M. Ladle. 1991. Comparison of rod catch data and known numbers of Atlantic salmon (Salmo salar) recorded by a resistivity fish counter in a southern chalk stream. In Cowx, I. G. (ed.), Catch Effort Sampling Strategies, Their Application in Freshwater Fisheries Management. Fishing News Books, Oxford: 49–60.Google Scholar
  7. Bennion, H., E. Shilland & P. Abbleby, 2003. An assessment of recent environmental change in Llyn Tegid using the sediment record. In Gritten, R. H., C. A. Duigan & H. Millband (eds), The Ecology, Conservation and Environmental History of the Largest Lake in Wales. University of Liverpool, Liverpool: 153–168.Google Scholar
  8. Bisbal, G. A. & W. E. McConnaha, 1998. Consideration of ocean conditions in the management of salmon. Canadian Journal of Fish and Aquatic Sciences 55: 2178–2186.CrossRefGoogle Scholar
  9. Blackie, J. R. & M. D. Newson. 1986. The effects of foresty on the quantity and quality of runoff in upland Britain. In De L. G. Solbé, J. F. (ed.). Effects of Land Use on Fresh Waters Agriculture, Forestry, Mineral Exploitation, Urbanisation. Ellis Horwood Limited, Chichester: 398–412.Google Scholar
  10. Brett, J. R., 1979. Environmental factors and growth. In Hoar, W. S., D. J. Randall & J. R. Brett (eds), Fish Physiology, Vol. 8. Academic Press, London: 599–675.Google Scholar
  11. Chadwick, E. M. P., 1987. Causes of variable recruitment in a small Atlantic salmon stock. American Fisheries Society Symposium 1: 390–401.Google Scholar
  12. Charlesworth, B., 1980. Evolution in Age-Structured Populations. Cambridge University Press, Cambridge.Google Scholar
  13. Churchward, A. S. & P. Hickley, 1991. The Atlantic salmon fishery of the River Severn (UK). In Cowx, I. G. (ed.), Catch Effort Sampling Strategies, Their Application in Freshwater Fisheries Management. Fishing news Books, Oxford: 1–14.Google Scholar
  14. Consuegra, S., C. García de Leániz, A. Serdio & A. Verspoor, 2005. Selective exploitation of early running fish may induce genetic and phenotypic changes in Atlantic salmon. Journal of Fish Biology 67(Supplement A): 129–145.CrossRefGoogle Scholar
  15. Cragg-Hine D., D. C. Bradley & K. Hendry, 2006. Changes in salmon smolt ages in the Welsh River Dee over a sixty-six year period. Journal of Fish Biology 68: 1891–1895.CrossRefGoogle Scholar
  16. Crozier, W. W. & G. J. A. Kennedy, 1999. Relationships between marine growth and marine survival of one sea winter Atlantic salmon, Salmon salar L. from the River Bush. Northern Ireland Fisheries Management and Ecology 6: 89–96.CrossRefGoogle Scholar
  17. Crozier, W. W. & G. J. A. Kennedy, 2001. Relationship between freshwater angling catch of Atlantic salmon and stock size in the River Bush, Northern Ireland. Journal of Fish Biology 58: 240–247.CrossRefGoogle Scholar
  18. Davidson, I. C., R. J. Cove, N. J. Milner & W. K. Purvis, 1996. Estimation of Atlantic salmon (Salmon salar, L.) and sea trout (Salmo trutta, L.) run size and angling exploitation on the Welsh Dee using mark-recapture and trap indices. In I. G. Cowx, (ed.), Stock Assessment in Inland Fisheries. Fishing News Books, Blackwell Science, Oxford: 293–307.Google Scholar
  19. Davidson, I. C. & M. S. Hazlewood, 2005. Effect of climate change on salmon fisheries. Environment Agency Science Report W2-047/SR. Environment Agency, Bristol.Google Scholar
  20. Davidson, I. C., M. S. Hazelwood & R. J. Cove, 2006. Predicted growth of juvenile trout and salmon in four rivers in England and Wales based on past and possible future temperature regimes linked to climate change. In Harris, G. S. & N. J. Milner (eds), Sea Trout: Biology, Conservation and Management. Proceedings of First International Sea Trout Symposium, Cardiff, July 2004. Fishing News Books. Blackwell Scientific Publications, Oxford: 401–416.Google Scholar
  21. Dempson, J. B., C. C. Mullins, C. Bourgeois, M. F. O’Connell & D. G. Reddin, 2003. Perspectives on smolt production and marine survival of Newfoundland Atlantic salmon (Salmo salar L.) to smolt size and run timing. In Potter, E. C. N., N. Ó. Maoiléidigh & G. Chaput (eds). Marine Mortality of Atlantic Salmon, Salmo salar L: Methods and Measures. Department of Fisheries and Oceans Canadian Science Advisory Secretariat Research Document 2003/101, 27–43.Google Scholar
  22. Egglishaw, H. J. & P. E. Shackley, 1977. Growth, survival and production of juvenile salmon and trout in a Scottish stream. Journal of Fish Biology 11: 647–672.CrossRefGoogle Scholar
  23. Elliott, J. M., 1994. Quantitative Ecology and the Brown Trout. Oxford University Press, Oxford.Google Scholar
  24. Elliott, J. M., 2001. The relative role of density in the stock-recruitment relationship of salmonids. In Prévost, E. & G. Chaput (eds), Stock Recruitment and Reference Points Assessment and Management of Atlantic Salmon. INRA, Paris: 25–66.Google Scholar
  25. Elliott, J. M. & M. A. Hurley, 1997. A functional model for maximum growth of Atlantic salmon parr, Salmo salar, from two populations in Northwest England. Functional Ecology 11: 592–603.CrossRefGoogle Scholar
  26. Elliott, J. M., M. A. Hurley & S. C. Maberly, 2000. The emergence period of sea trout fry in a Lake District stream correlates with the North Atlantic Oscillation. Journal of Fish Biology 56: 208–210.CrossRefGoogle Scholar
  27. Environment Agency, 1998. Salmon Action Plan Guidelines, Version 2. Environment Agency, Bristol.Google Scholar
  28. Friedland, K. D., 1998. Ocean climate influences on critical Atlantic salmon (Salmo salar) life history events. Canadian Journal of Fish and Aquatic Sciences 55: 119–130.CrossRefGoogle Scholar
  29. Friedland, K. D., L. P. Hansen, D. A. Dunkley & J. C. Maclean. 2000. Linkage between ocean climate, post-smolt growth and survival of Atlantic salmon (Salmo salar, L.) in the North Sea area. ICES Journal of Marine Science 57: 419–429.CrossRefGoogle Scholar
  30. Friedland, K. D. & R. E. Hass, 1996. Marine post-smolt growth and age maturity of Atlantic salmon. Journal of Fish Biology 48: 1–15.CrossRefGoogle Scholar
  31. Friedland, K. D., D. G. Reddin & M. Castonguay, 2003. Ocean thermal conditions in the post-smolt nursery of North American Atlantic salmon. ICES Journal of Marine Science 60: 343–355.CrossRefGoogle Scholar
  32. García de Leániz, C., A. Serdio & S. Consuegra, 2001. Present status of Atlantic salmon in Cantabria. In García de Leániz, C., A. Serdio & S. Consuegra (eds), El Salmón, Joya de Nuestros Ríos, Consejería de Ganadería, Agricultura y Pesca, Santander: 55–82.Google Scholar
  33. Gardner, M. L. G., 1976. A review of factors which may influence the sea-age and maturation of Atlantic salmon, Salmo salar. Journal of Fish Biology 9: 289–327.CrossRefGoogle Scholar
  34. Gargan, P., J. Stafford & N. O. Maoiléidigh, 2001. The relationship between salmon rod catch, stock size, rod exploitation and rod effort on the Erriff fishery western Ireland. In Shelton, R. (ed.), The Interpretation of Rod and Net Catch Data. The Atlantic Salmon Trust, Pitlochry: 68–75.Google Scholar
  35. Gee, A. S. & N. J. Milner. 1980. Analysis of 70-year catch statistics for Atlantic salmon (Salmo salar) in the River Wye and implications for management of the stocks. Journal of Applied Ecology 17:41–57.CrossRefGoogle Scholar
  36. George, A. F., 1984. Scottish salmon and grilse return-migration variations over 200 years. In Holden, A. H. (ed.), Proceedings of the Institute of Fisheries Management 15th Annual Study Course. Stirling University. Institute of Fisheries Management, Nottingham: 23–32.Google Scholar
  37. George, A. F., 1991. Climate and the Salmon. Salmon. Trout and Sea-Trout. December 1991.Google Scholar
  38. Gibson, R. J., 1993. The Atlantic salmon in freshwater: Spawning, rearing and production. Reviews in Fish Biology and Fisheries 3: 39–73.CrossRefGoogle Scholar
  39. Gough, P. G., A. J. Winstone & P. G. Hilder, 1992. Spring salmon a review of factors affecting the abundance and catch of spring salmon from the River Wye and else-where, and proposals for stock maintenance and enhancement. National Rivers Authority Welsh Region Technical Fisheries Report. No. 2. National Rivers Authority, Bristol.Google Scholar
  40. Gudjonsson, S., S. M. Einarsson, Th. Antonsson & G. Gudbergsson, 1995. Relation of grilse to salmon ratio to environment changes in several wild stocks of Atlantic salmon (Salmo salar) in Iceland. Canadian Journal of Fish and Aquatic Sciences 52:1385–1398.CrossRefGoogle Scholar
  41. Hansen, L. P., 2001. Relationship between catches, rod exploitation and total run of Atlantic salmon in the River Drammenselv, Norway. In Shelton, R. (ed.), The Interpretation of Rod and Net Catch Data. The Atlantic Salmon Trust, Pitlochry: 85–90.Google Scholar
  42. Hawkins, A. D. & G. W. Smith, 1986. Radio-tracking observations on Atlantic salmon ascending the Aberdeenshire Dee. Scottish Fisheries Research Report 36.Google Scholar
  43. Heddell-Cowie, M., 2005. Importance of the River Teviot to Atlantic salmon, Salmonsalar, rod catches in the River Tweed, Scotland. Fisheries Management and Ecology 12: 137–142.CrossRefGoogle Scholar
  44. Heller, M. D., 1992. pH and flow in the Afon Alwen and Afon Brenig below the reservoirs. National Rivers Authority, Technical Memorandum, EAU/92/TM05. National Rivers Authority, Cardiff.Google Scholar
  45. Hendry, K., D. Cragg-Hine, M. O’Grady, H. Sambrook & A. Stephens, 2003. Management of habitat for rehabilitation and enhancement of salmonid stocks. Fisheries Research 62: 171–192.CrossRefGoogle Scholar
  46. Hodgson, P. B., 1993. The ecology and management of the coarse fish populations of the lower Welsh Dee. Ph.D. Thesis, University of Liverpool, Liverpool.Google Scholar
  47. Hodgson, P. B., A. E. Weston & T. P. Westwood, 1980. Environmental factors influencing the management of the canalised estuarial reaches of the regulated River Dee. Paper presented at the Annual General Meeting of the Water Engineers and Scientists.Google Scholar
  48. Holtby, L. B. & M. C. Healey, 1990. Sex-specific life-history tactics and risk-taking in coho salmon. Ecology 71: 678–690.CrossRefGoogle Scholar
  49. Hutchings, J. A. & M. E. B. Jones, 1998. Life history variation and growth rate thresholds for maturity in Atlantic salmon, Salmo salar. Canadian Journal of Fish and Aquatic Sciences 55(Supplement 1): 22–47.CrossRefGoogle Scholar
  50. ICES, 2004. Report of the working Group on North Atlantic salmon. Halifax, Canada, 29 March-8 April 2004. International Council for the Exploration of the Sea C.M.2004/ACFM: 20.Google Scholar
  51. Imre, I., J. W. A. Grant & R. A. Cunjak, 2005. Density-dependent growth of young-of-the-year Atlantic salmon Salmo salar in Catamaran Brook, New Brunswick. Journal of Animal Ecology 74: 508–516.Google Scholar
  52. Jenkins, T. M., Jr., S. Diehl, K. W. Kratz & S. D. Cooper. 1999. Effects of population density on individual growth of brown trout in streams. Ecology 80: 941–956.CrossRefGoogle Scholar
  53. Jones, J. W., 1939. Salmon of the Cheshire Dee, 1937 and 1938. Transactions of the Liverpool Biological Society 52: 19–79.Google Scholar
  54. Jones, J. W., 1949. Studies of the scales of young salmon (Salmo salar L. (Juv.)) in relation to growth, migration and spawning. Fisheries Investigations Series I, V.Google Scholar
  55. Jones, J. W., 1950. Salmon of the Cheshire Dee. Fisheries Investigations, Series 1, V, No. 3.Google Scholar
  56. Jones, J. W., 1959. The Salmon. Collins, London.Google Scholar
  57. Kennedy, G. J. A. & W. W. Crozier, 1995. Factors affecting recruitment success in salmonids. In Harper, D. M. & A. J. D. Ferguson (eds), The Ecological Basis for River Management. John Wiley & Sons Ltd., Chichester: 349–362.Google Scholar
  58. Laird, L. M., 1976. Growth and movements of juvenile Atlantic salmon and brown trout in the Afon Mynach. Ph.D. Thesis, University of Liverpool, Liverpool.Google Scholar
  59. Laughton, R. & G. W. Smith, 1992. The relationship between the date of river entry and the estimated spawning position of adult Atlantic salmon (Salmo salar L.) in two major Scottish east coast rivers. In Priede, I. G., & S. M. Swift (eds). Wildlife Telemetry: Remote Monitoring and Tracking of Animals. Ellis Horwood, New York: 423–433.Google Scholar
  60. Lees, P. R., 1972. The salmonid fish of the rivers Dee and Clwyd. Ph.D. Thesis, University of Liverpool, Liverpool.Google Scholar
  61. Lobón-Cerviá, J., 2005. Spatial and temporal variation in the influence of density dependence on growth of stream-living brown trout (Salmo trutta). Canadian Journal of Fish and Aquatic Sciences 62: 1231–1242.CrossRefGoogle Scholar
  62. Lundqvist, H., S. Mckinnell, H. Fängstam & I. Berglund, 1994 The effect of time, size and sex on recapture rates and yield after river releases of Salmo salar smolts. Aquaculture 121: 245–257.CrossRefGoogle Scholar
  63. MacLean, J. C., A. F. Youngson & R. J. Fryer, 2001. The use of rod catch data in assessing trends in relative abundance. In Shelton, R. (ed.), The Interpretation of Rod and Net Catch Data. The Atlantic Salmon Trust, Pitlochry: 91–99.Google Scholar
  64. Martin, J. H. A. & K. A. Mitchell, 1985. Influence of sea temperature upon the numbers of grilse and multi-seawinter Atlantic salmon (Salmo salar) caught in the vieinity of the River Dee (Aberdeenshire). Canadian Journal of Fish and Aquatic Sciences 42: 1513–1521.CrossRefGoogle Scholar
  65. Mayall, S., 2003. Development of flow regulation in the River Dee catchment and the associated impacts on the level regime at Llyn Tegid. In Gritten, R. H., C. A. Duigan & H. Millband (eds), The Ecology, Conservation and Environmental History of the Largest Lake in Wales. University of Liverpool, Liverpool: 49–57.Google Scholar
  66. Metcalfe, N. B., F. A. Huntingford, W. D. Graham & J. E. Thorpe, 1989. Early social status and the development of life-history strategies in Atlantic salmon. Proceedings of the Royal Society London B 236: 7–19.Google Scholar
  67. Milner, N. J., I. C. Davidson, R. E. Evans, V. Locke & R. J. Wyatt, 2001. The use of rod catches to estimate salmon runs in England and Wales. In Shelton, R., (ed.), The Interpretation of Rod and Net Catch Data. The Atlantic Salmon Trust, Pitlochry: 46–67.Google Scholar
  68. Milner, N. J., I. C. Davidson, R. J. Wyatt & M. W. Aprahamian. 2000. The application of biological targets to the management of salmon recreational fisheries in England and Wales. In Cowx, I. G. (ed.), Management and Ecology of River Fisheries. Fishing News Books, Oxford: 361–372.CrossRefGoogle Scholar
  69. Moffett, I. J. J., M. Allen, C. F. Flanagan, W. W. Crozier & G. J. A. Kennedy, 2006. Fecundity, egg size and early hatchery survival for wild Atlantic salmon, from the River Bush. Fisheries Management and Ecology 13: 73–79.CrossRefGoogle Scholar
  70. Moore, D. S., G. L. Chaput & P. R. Pickard, 1995. The effect of fisheries on the biological characteristics and survival of mature Atlantic salmon (Salmo salar) from the Miramichi river. In Chadwick, E. M. P. (ed.), Water, Science and the Public: The Miramichi Ecosystem. Special Publications of Canadian Journal of Fisheries and Aquatic Science 123: 229–247.Google Scholar
  71. Moore, A. & C. P. Waring. 2001. The effects of a synthetic pyrethroid pesticide on some aspects of reproduction in Atlantic salmon (Salmo salar L.). Aquatic Toxicology 52: 1–12.PubMedCrossRefGoogle Scholar
  72. NASCO, 1999. Request for Scientific Advice from ICES. Report of the Sixteenth Annual Meeting of the Council, Annex 8. NASCO, Edinburgh.Google Scholar
  73. Økland, F., D. Jonsson, A. J. Jensen & L. P. Hansen, 1993. Is there a threshold size regulating seaward migration of brown trout and Atlantic salmon. Journal of Fish Biology 42: 541–550.Google Scholar
  74. Olsen, E. B., G. R. Lilly, M. Heino, M. J. Morgan, J. Brattey & U. Dieckmann. 2005. Assessing changes in age and size at maturation in collapsing populations of Atlantic cod (Gadus morhua). Canadian Journal of Fish and Aquatic Sciences 62: 811–823.CrossRefGoogle Scholar
  75. Pope, I. A., D. H. Mills & W. M. Shearer, 1961. The fecundity of the Atlantic salmon (Salmo salar Linn.). Freshwater and Salmon Fisheries Research. 26.Google Scholar
  76. Potter, E. C. E., J. C. MacLean, R. J. Wyatt & R. N. B. Campbell, 2003b. Managing the exploitation of migratory salmonids. Fisheries Research 62: 127–142.CrossRefGoogle Scholar
  77. Potter, E. C. E., N. Ó. Maoiléidigh & G. Chaput. 2003a. Marine Mortality of Atlantic Salmon, Salmo salar L. Methods and Measures. Department of Fisheries and Oceans Canadian Science Advisory Secretariat Research Document 2003/101.Google Scholar
  78. Prouzet, P., 1990. Stock characteristics of Atlantic salmon (Salmo salar) in France: A review. Aquatic Living Resources 3: 85–97.CrossRefGoogle Scholar
  79. Quinn, T. P., 2005. The Behaviour and Ecology of Pacific Salmon and Trout. University of Washington Press, Seattle.Google Scholar
  80. Quinn, T. P., P. McGinnity & T. F. Cross, 2006. Long-term declines in body size and shifts in run timing of Atlantie salmon in Ireland. Journal of Fish Biology 68: 1713–1730.CrossRefGoogle Scholar
  81. Rago, P. J., & C. P. Goodyear, 1987. Recruitment mechanisms of striped bass and Atlantic salmon; Comparative liabilities of alternative life histories. American Fisheries Society Symposium 1: 402–416.Google Scholar
  82. Reznick, D. N., H. Bryga & J. A. Endler, 1990. Experimentally induced life-history evolution in a natural population. Nature (London, U.K.) 346: 357–359.CrossRefGoogle Scholar
  83. Riddell, B. E., 1986. Assessment of selective fishing on the age at maturity in Atlantic salmon (Salmo salar): A genetic perspective. In Meerburg, D. J., (ed.), Salmonid Age at Maturity. Canadian special Publication of Fisheries and Aquatic Sciences 89: 102–109.Google Scholar
  84. Roff, D. A., 1992. The Evolution of Life Histories. Chapman & Hall, London.Google Scholar
  85. Russell, I. C. & E. C. E. Potter, 1996. Interception salmon fisheries — assessing their impact on national stocks. Proceedings of the Institute of Fisheries Management Study Course, Cardiff. Sept. 1993.Google Scholar
  86. Shearer, W. M., 1992. The Atlantic Salmon Natural History. Exploitation and Future Management. Fishing news Books, Oxford.Google Scholar
  87. Staurnes, M., L. P. Hansen, K. Fugelle & O. Haraldstad. 1996. Short-term exposure to acid water impairs osmoregulation, seawater tolerance, and subsequent marine survival of smolts of Atlantic salmon (Salmo salar). Canadian Journal of Fish and Aquatic Sciences 53: 1695–1704.CrossRefGoogle Scholar
  88. Stearns, S. C., 1992. The Evolution of Life Histories. Oxford University Press, Oxford.Google Scholar
  89. Summers, D. W., 1995. Long-term changes in the sea-age at maturity and seasonal time of return of salmon, Salmo salar L., to Scottish Rivers. Fisheries Management and Ecology 2: 147–155.CrossRefGoogle Scholar
  90. Thomson, A. G., & R. M. Fuller, 2003. An investigation of land use change in the Llyn Tegid catchment using satellite remote sensing. In Gritten, R. H., C. A. Duigan & H. Millband (eds), The Ecology, Conservation and Environmental History of the Largest Lake in Wales. University of Liverpool, Liverpool: 169–187.Google Scholar
  91. Turrell, W. R. & R. G. J. Shelton, 1993. Climatic change in the north-eastern Atlantic and its impacts on salmon stocks. In Mills, D. H. (ed.). Salmon in the Sea and New Enhancement Strategies. Fishing News Books, Oxford: 40–78.Google Scholar
  92. Webb, J. H., 1989. The Behaviour of Adult Salmon (Salmo salar L.) in the River Tay as Determined by Radio Telemetry. Scottish Fisheries Research Report, 44.Google Scholar
  93. Webb, J. H. & R. N. B. Campbell, 2000. Patterns of run timing in adult Atlantic salmon (Salmo salar L.) returning to Scottish rivers — some new perspectives and management implications. In Whoriskey, F. G., Jr. & K. B. Whelan (eds). Proceedings of the Fifth International salmon Symposium, Canada: 100–138.Google Scholar
  94. Whelan, K. F., B. J. Whelan & G. Rogan, 2001. Catch as a predictor of salmon stock in the Burrishoole fishery, Co. Mayo, western Ireland. In Shelton, R. (ed.), The Interpretation of Rod and Net Catch Data. The Atlantic Salmon Trust, Pitlochry: 76–84.Google Scholar
  95. Woolland, J. V., 1972. Studies on Salmonid Fishes in Llyn Tegid and the Welsh Dee. Ph.D. Thesis, University of Liverpool, Liverpool.Google Scholar
  96. Youngson, A. F., 1995. Spring Salmon 1994 Bensinger-Liddell Memorial Fellowship. Atlantic Salmon Trust, Pitlochry.Google Scholar
  97. Youngson, A. F., J. C. MacLean, & R. J. Fryer. 2002. Rod catch trends for early-running MSW salmon in Scottish rivers (1952–1997): Divergence among stock components. ICES Journal of Marine Science 59: 836–849.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Miran W. Aprahamian
    • 1
  • Ian C. Davidson
    • 2
  • Richard J. Cove
    • 2
  1. 1.Environment AgencyRichard Fairclough HouseWarringtonUK
  2. 2.Environment AgencyBuckleyUK

Personalised recommendations