Atlantic Salmon Ecology

Foreword.

Preface and acknowledgements.

Reviewers.

Contributors.

Glossary.

1 Aquatic Nomads: The Life and Migrations of the Atlantic Salmon.

Eva B. Thorstad, Fred Whoriskey, Audun H. Rikardsen & Kim Aarestrup

1.1 Introduction.

1.2 Atlantic salmon life cycle.

1.3 Geographic distribution.

1.4 Smolt and post-smolt migration – from juvenile life in the river to feeding in the ocean.

1.4.1 Downriver smolt migration.

1.4.2 Marine post-smolt migration.

1.5 Spawning migration – from feeding in the ocean to spawning in the river.

1.5.1 Returning from ocean feeding grounds and entering the rivers.

1.5.2 Upstream river migration.

1.5.3 Factors affecting the upstream river migration.

1.6 Kelt migration – after spawning and during outward migration.

1.7 Homing and orientation mechanisms.

1.8 Conclusion and future research needs.

References.

2 Reproductive Ecology: A Tale of Two Sexes.

Ian A. Fleming & Sigurd Einum

2.1 Introduction.

2.2 Reproductive strategies: age and size at maturity.

2.2.1 Among populations.

2.2.2 Within populations and the evolution of alternative reproductive phenotypes.

2.2.3 Anadromous and resident phenotypes.

2.3 Reproductive investment.

2.3.1 Differences between the sexes.

2.3.2 Differences between reproductive phenotypes.

2.3.3 Survival costs.

2.4 Breeding behaviour and success.

2.4.1 Females.

2.4.2 Anadromous males.

2.4.3 Mature male parr.

2.5 Reproductive success through effects on the next generation.

2.5.1 Egg and larvae development.

2.6 Maternal influences on offspring.

2.6.1 Egg size.

2.6.2 Spawning time.

2.6.3 Spawning location and consequences for population productivity.

References.

3 Freshwater Habitat Requirements of Atlantic Salmon.

Anders G. Finstad, John D. Armstrong & Keith H. Nislow

3.1 Introduction.

3.2 The fundamental niche and freshwater habitat requirements.

3.2.1 Scope for growth.

3.2.2 Trading off growth and survival.

3.3 Realised niche and observed habitat use.

3.4 Large-scale determinants of Atlantic salmon habitat.

3.5 Managing Atlantic salmon freshwater habitats.

3.5.1 General principles.

3.5.2 Optimum habitat-production landscapes.

3.5.3 Management strategies.

3.5.4 Reference conditions and habitat management.

3.5.5 The future.

References.

4 The When, What and Where of Freshwater Feeding.

Morten Johansen, Jaakko Erkinaro & Per-Arne Amundsen

4.1 Introduction.

4.2 Diet selectivity.

4.3 Drift vs. benthic feeding.

4.4 Ontogenetic changes in diet.

4.4.1 Fry.

4.4.2 Parr.

4.4.3 Smolt.

4.4.4 Adults.

4.5 Temporal feeding patterns.

4.5.1 Day vs. night.

4.5.2 Season.

4.6 Spatial feeding patterns.

4.6.1 Microhabitat scale.

4.6.2 Mesohabitat scale.

4.6.3 Habitat scale.

4.7 Interspecific food resource partitioning.

4.8 Concluding remarks and future perspectives.

References.

5 Dietary Life-Support: The Food and Feeding of Atlantic Salmon at Sea.

Audun H. Rikardsen & J. Brian Dempson

5.1 Introduction.

5.2 Post-smolt nearshore feeding.

5.2.1 Geographical and annual differences.

5.3 Open ocean feeding of post-smolts.

5.3.1 Post-smolt diet in the open ocean.

5.4 Open ocean feeding of pre-adults and adult pre-spawning salmon.

5.4.1 Northwest Atlantic Ocean.

5.4.2 Northeast Atlantic Ocean.

5.5 Summary and conclusions.

Acknowledgements.

References.

6 The Behavioural Flexibility of Salmon Growth.

Torbjørn Forseth, Benjamin H. Letcher & Morten Johansen

6.1 Introduction.

6.2 Patterns of Atlantic salmon growth.

6.3 Environmental sources of growth variation.

6.3.1 Abiotic factors.

6.3.2 Biotic factors.

6.4 Maternal sources of growth variation.

6.5 Genetic sources of growth variation.

6.6 Constraints to growth.

6.7 Growth modelling.

6.7.1 Laboratory models.

6.7.2 Field-based models.

6.8 Perspectives for management.

References.

7 The Role of Competition in the Ecology of Juvenile Atlantic Salmon.

Keith H. Nislow, John D. Armstrong & James W. A. Grant

7.1 Introduction.

7.2 Intraspecific competition.

7.2.1 Intracohort interactions.

7.2.2 Intercohort competition.

7.2.3 Competition among wild and farmed Atlantic salmon.

7.3 Interspecific competition.

7.3.1. Species assemblages in Atlantic salmon rivers.

7.3.2 Competitors other than fish.

7.3.3 Non-salmonid fishes as competitors.

7.3.4 Competition with other salmonid species.

7.4 Conclusions.

References.

8 Predation: Compensation and Context Dependence.

Darren M. Ward & Nils A. Hvidsten

8.1 Introduction.

8.2 Major salmon predators.

8.2.1 Eggs.

8.2.2 Fry.

8.2.3 Parr.

8.2.4 Smolts.

8.2.5 Post-smolts in estuaries.

8.2.6 Post-smolts at sea.

8.2.7 Adults.

8.3 Conceptual models of predation.

8.3.1 Additive and compensatory mortality.

8.3.2 Functional response.

8.3.3 Predator abundance.

8.3.4 Trait-mediated effects.

8.3.5 Implications of predation for salmon populations.

8.3.6 Predator control.

8.4 Conclusions.

References.

9 The Parasites and Pathogens of the Atlantic Salmon: Lessons from. Gyrodactylus salaris.

Phil D. Harris, Lutz Bachmann & Tor A. Bakke

9.1 Introduction.

9.2 The parasite community of Atlantic salmon.

9.2.1 The parasite community of freshwater immature stages.

9.2.2 The parasite community of salmon in the sea.

9.2.3 The parasite community in adult fish returning to fresh water.

9.3. G... salaris. and the epidemiological triangle.

9.3.1. G. salaris: ‘The Russian doll killer’.

9.3.2 The agent: pathogenic or benign? Taxonomic issues surrounding. G. salaris.

9.3.3 The physicochemical environment: The role of environment in shaping infection outcomes.

9.4 Managing disease in wild salmonid populations.

References.

10 The Effect of Sea Lice on Atlantic Salmon and other Salmonid Species.

Bengt Finstad, Pål A. Bjørn, Christopher D. Todd, Fred Whoriskey, Patrick G. Gargan, Gregory Forde & Crawford W. Revie

10.1 Introduction.

10.1.1 Sea lice biology.

10.1.2 General effects of sea lice on fish physiology.

10.1.3 General effects of sea lice on fish populations.

10.2 The sea lice story from Norway.

10.2.1 Historical data.

10.2.2 Infestation levels of Atlantic salmon post-smolts.

10.2.3 Sea lice effects on Atlantic salmon – adult returns.

10.3 The sea lice story from Canada.

10.3.1 Historical data.

10.3.2 Effects of sea lice on Atlantic salmon – east coast.

10.3.3 Effects of sea lice on salmonids – west coast.

10.4 The sea lice story from Ireland.

10.4.1 Effects of sea lice on Atlantic salmon.

10.4.2 Effects of sea lice on sea trout.

10.5 The sea lice story from Scotland.

10.5.1 Historical data.

10.5.2 Effects of sea lice on Atlantic salmon.

10.6 Management.

10.6.1 Sea lice management in Norway.

10.6.2 Sea lice management in Canada.

10.6.3 Sea lice management in Ireland.

10.6.4 Sea lice management in Scotland.

10.7 Concluding remarks.

References.

11 Variation in Population Size through Time and Space: Theory and Recent Empirical Advances from Atlantic Salmon.

Sigurd Einum & Keith H. Nislow

11.1 Introduction.

11.2 Temporal variation in Atlantic salmon abundance.

11.2.1 Density dependence vs. density independence.

11.2.2 Empirical evidence for density dependence in Atlantic salmon.

11.3 Environmental influences on population dynamics.

11.4 Density dependence throughout the juvenile stage.

11.5 Spatial aspects of density dependence.

References.

12 Stock, Recruitment and Exploitation.

Kjetil Hindar, Jeffrey A. Hutchings, Ola H. Diserud & Peder Fiske

12.1 Introduction.

12.2 State of Atlantic salmon populations.

12.2.1 Migratory populations.

12.2.2 Non-migratory populations.

12.3 Stock and recruitment in Atlantic salmon populations.

12.3.1 Spatial variation in stock and recruitment relationships.

12.3.2 Temporal variation in SR relationships.

12.4 Spawning targets: from single populations to nation-wide levels.

12.4.1 Methodology – transfer from data-rich to data-poor rivers.

12.4.2 Spawning targets for North America.

12.4.3 Spawning targets for Europe.

12.4.4 Spawning target uncertainties.

12.5 Exploitation.

12.5.1 History of exploitation.

12.5.2 Exploitation rates.

12.5.3 Composition of catches.

12.6 Evolutionary and ecological effects of fishing.

12.7 Management implications.

References.

13 Landscape and Land Use Effects on Atlantic Salmon.

Ola Ugedal & Anders G. Finstad

13.1 Introduction.

13.2 The multiple spatial scales of freshwater productivity.

13.2.1 Global and regional scales.

13.2.2 Catchment and reach scales.

13.3 Land use and Atlantic salmon.

13.3.1 Global trends.

13.3.2 Catchment effects.

13.4 Concluding remarks.

References.

14 Hydropower Development – Ecological Effects.

Bjørn Ove Johnsen, Jo Vegar Arnekleiv, Lars Asplin, Bjørn T. Barlaup, Tor F. Næsje, Bjørn Olav Rosseland, Svein Jakob Saltveit & Arve Tvede

14.1 Introduction.

14.2 Changes in physical, chemical, hydrological and biologicalfactors in rivers and fjord systems as a consequence of hydropower development.

14.2.1 River systems.

14.2.2 Fjord systems.

14.3 Changes in survival, growth, migration and production of salmon in rivers and fjords.

14.3.1 Rivers.

14.3.2 Fjord systems.

14.4 Measures to compensate for negative effects of hydropower development.

14.4.1 Use of biological and physical measures.

14.5 Conclusion.

References.

15 Lessons from Acidification and Pesticides.

Bjørn Olav Rosseland & Frode Kroglund

15.1 General water quality of Atlantic salmon rivers.

15.2 Major classes of pollutants.

15.3 Acidification.

15.4 Pesticides and Atlantic salmon.

15.5 Conclusion.

References.

16 Getting into Hot Water? Atlantic Salmon Responses to Climate Change in Freshwater and Marine Environments.

Christopher D. Todd, Kevin D. Friedland, Julian C. MacLean, Neil Hazon & Arne J. Jensen

16.1 Introduction.

16.2 Past and present climate for Atlantic salmon.

16.3 Upstream river migration and spawning.

16.4 Eggs and alevins.

16.5 Parr life.

16.6 Smolt migration.

16.7 Geographical distribution and recent trends in adult stock abundance.

16.8 Ocean climate influences on run-timing and adult abundance/recruitment.

16.9 Migration, diurnal behaviour and changes in the epipelagic food web.

16.10 Do changes in North Atlantic zooplankton communities comprise regime shifts?.

16.11 Change in size and growth in the marine environment.

16.12 Adult somatic condition and lipid reserves: indicators of ocean climate deterioration?.

16.13 Maturity schedules.

16.14 Large-scale indicator indices of ocean climate change and impacts on salmon.

16.15 Management issues and responses to changes in ocean climate.

References.

17 Salmon Ecological Research and Conservation.

Øystein Aas, David Policansky, Sigurd Einum & Jostein Skurdal

17.1 Introduction.

17.2 Ecological research that contributes to conservation.

17.3 Environment, genetics, and changes in life-history.

17.4 Enhanced cooperation.

17.5 Multidisciplinary science.

References.

Index.