Atlantic Salmon Ecology

Atlantic Salmon Ecology......Page 5
Contents......Page 7
Foreword......Page 15
Preface and acknowledgments......Page 17
Reviewers......Page 19
Contributors......Page 21
Glossary......Page 25
1.1 Introduction......Page 31
1.2 Atlantic salmon life cycle......Page 34
1.3 Geographic distribution......Page 37
1.4.1 Downriver smolt migration......Page 38
1.4.2 Marine post-smolt migration......Page 41
1.5.1 Returning from ocean feeding grounds and entering the rivers......Page 42
1.5.2 Upstream river migration......Page 44
1.5.3 Factors affecting the upstream river migration......Page 46
1.7 Homing and orientation mechanisms......Page 50
1.8 Conclusion and future research needs......Page 52
References......Page 53
2.1 Introduction......Page 63
2.2.1 Among populations......Page 65
2.2.2 Within populations and the evolution of alternative reproductive phenotypes......Page 67
2.2.3 Anadromous and resident phenotypes......Page 70
2.3.1 Differences between the sexes......Page 71
2.3.3 Survival costs......Page 72
2.4.1 Females......Page 73
2.4.2 Anadromous males......Page 76
2.4.3 Mature male parr......Page 77
2.5.1 Egg and larvae development......Page 78
2.6.1 Egg size......Page 79
2.6.2 Spawning time......Page 82
2.6.3 Spawning location and consequences for population productivity......Page 83
References......Page 85
3.1 Introduction......Page 97
3.2.1 Scope for growth......Page 99
3.2.2 Trading off growth and survival......Page 101
3.3 Realised niche and observed habitat use......Page 103
3.4 Large-scale determinants of Atlantic salmon habitat......Page 107
3.5.1 General principles......Page 108
3.5.2 Optimum habitat-production landscapes......Page 110
3.5.3 Management strategies......Page 111
3.5.5 The future......Page 112
References......Page 113
4: The When, What and Where of Freshwater Feeding......Page 119
4.2 Diet selectivity......Page 120
4.3 Drift vs. benthic feeding......Page 126
4.4 Ontogenetic changes in diet......Page 128
4.4.3 Smolt......Page 129
4.5 Temporal feeding patterns......Page 130
4.5.2 Season......Page 131
4.6 Spatial feeding patterns......Page 132
4.6.2 Mesohabitat scale......Page 133
4.6.3 Habitat  scale......Page 134
4.7 Interspecific food resource partitioning......Page 135
References......Page 137
5.1 Introduction......Page 145
5.2 Post-smolt nearshore feeding......Page 147
5.2.1 Geographical and annual differences......Page 148
5.3 Open ocean feeding of post-smolts......Page 153
5.3.1 Post-smolt diet in the open ocean......Page 154
5.4 Open ocean feeding of pre-adults and adult pre-spawning salmon......Page 156
5.4.1 Northwest Atlantic Ocean......Page 157
5.4.2 Northeast Atlantic Ocean......Page 160
5.5 Summary and conclusions......Page 161
Acknowledgements......Page 165
References......Page 166
6.1 Introduction......Page 175
6.2 Patterns of Atlantic salmon growth......Page 177
6.3.1 Abiotic factors......Page 181
6.3.2 Biotic factors......Page 183
6.4 Maternal sources of growth variation......Page 184
6.5 Genetic sources of growth variation......Page 185
6.6 Constraints to growth......Page 187
6.7.1 Laboratory models......Page 188
6.7.2 Field-based models......Page 190
References......Page 191
7.1 Introduction......Page 201
7.2 Intraspecific competition......Page 202
7.2.1 Intracohort interactions......Page 203
7.2.2 Intercohort competition......Page 208
7.3.1. Species assemblages in Atlantic salmon rivers......Page 212
7.3.3 Non-salmonid fishes as competitors......Page 215
7.3.4 Competition with other salmonid species......Page 216
7.4 Conclusions......Page 219
References......Page 220
8.1 Introduction......Page 229
8.2 Major salmon predators......Page 230
8.2.2 Fry......Page 231
8.2.4 Smolts......Page 233
8.2.5 Post-smolts in estuaries......Page 234
8.3 Conceptual models of predation......Page 236
8.3.1 Additive and compensatory mortality......Page 237
8.3.2 Functional response......Page 239
8.3.3 Predator abundance......Page 242
8.3.5 Implications of predation for salmon populations......Page 243
8.3.6 Predator control......Page 244
References......Page 245
9.1 Introduction......Page 251
9.2 The parasite community of Atlantic salmon......Page 254
9.2.1 The parasite community of freshwater immature stages......Page 256
9.2.2 The parasite community of salmon in the sea......Page 258
9.2.3 The parasite community in adult fish returning to fresh water......Page 259
9.3.1 G. salaris: ‘The Russian doll killer’......Page 260
9.3.2 The agent: pathogenic or benign? Taxonomic issues surrounding G. salaris......Page 261
9.3.3 The physicochemical environment: The role of environment in shaping infection outcomes......Page 267
9.4 Managing disease in wild salmonid populations......Page 271
References......Page 274
10.1 Introduction......Page 283
10.1.1 Sea lice biology......Page 284
10.1.2 General effects of sea lice on fish physiology......Page 286
10.1.3 General effects of s ea lice on fish populations......Page 288
10.2.1 Historical data......Page 289
10.2.2 Infestation levels of Atlantic salmon post-smolts......Page 290
10.3.1 Historical data......Page 291
10.3.3 Effects of sea lice on salmonids – west coast......Page 292
10.4.2 Effects of sea lice on sea trout......Page 293
10.5.1 Historical data......Page 294
10.6 Management......Page 295
10.6.2 Sea lice management in Canada......Page 296
10.6.4 Sea lice management in Scotland......Page 297
10.7 Concluding remarks......Page 298
References......Page 299
11.1 Introduction......Page 307
11.2 Temporal variation in Atlantic salmon abundance......Page 309
11.2.1 Density dependence vs. density independence......Page 310
11.2.2 Empirical evidence for density dependence in Atlantic salmon......Page 314
11.3 Environmental influences on population dynamics......Page 316
11.4 Density dependence throughout the juvenile stage......Page 318
11.5 Spatial aspects of density dependence......Page 321
References......Page 325
12.1 Introduction......Page 329
12.2 State of Atlantic salmon populations......Page 332
12.2.1 Migratory populations......Page 333
12.3 Stock and recruitment in Atlantic salmon populations......Page 336
12.3.1 Spatial variation in stock and recruitment relationships......Page 340
12.3.2 Temporal variation in SR relationships......Page 342
12.4.1 Methodology – transfer from data-rich to data-poor rivers......Page 343
12.4.2 Spawning targets for North America......Page 344
12.4.3 Spawning targets for Europe......Page 346
12.4.4 Spawning target uncertainties......Page 347
12.5.1 History of exploitation......Page 349
12.5.2 Exploitation rates......Page 351
12.6 Evolutionary and ecological effects of fishing......Page 352
12.7 Management implications......Page 353
References......Page 355
13.1 Introduction......Page 363
13.2.1 Global and regional scales......Page 364
13.2.2 Catchment and reach scales......Page 366
13.3 Land use and Atlantic salmon......Page 369
13.3.1 Global trends......Page 370
13.3.2 Catchment effects......Page 371
13.4 Concluding remarks......Page 375
References......Page 376
14: Hydropower Development – Ecological Effects......Page 381
14.1 Introduction......Page 382
14.2.1 River systems......Page 386
14.2.2 Fjord systems......Page 390
14.3.1 Rivers......Page 392
14.3.2 Fjord systems......Page 397
14.4 Measures to compensate for negative effects of hydropower development......Page 398
14.4.1 Use of biological and physical measures......Page 399
14.5 Conclusion......Page 404
References......Page 406
15.1 General water quality of Atlantic salmon rivers......Page 417
15.2 Major classes of pollutants......Page 418
15.3 Acidification......Page 419
15.4 Pesticides and Atlantic salmon......Page 424
References......Page 428
16.1 Introduction......Page 439
16.2 Past and present climate for Atlantic salmon......Page 440
16.3 Upstream river migration and spawning......Page 442
16.4 Eggs and alevins......Page 443
16.5 Parr life......Page 444
16.6 Smolt migration......Page 446
16.7 Geographical distribution and recent trends in adult stock abundance......Page 449
16.8 Ocean climate influences on run-timing and adult abundance/recruitment......Page 451
16.9 Migration, diurnal behaviour and changes in the epipelagic food web......Page 453
16.10 Do changes in North Atlantic zooplankton communities comprise regime shifts?......Page 454
16.11 Change in size and growth in the marine environment......Page 455
16.12 Adult somatic condition and lipid reserves: indicators of ocean climate deterioration?......Page 456
16.13 Maturity schedules......Page 457
16.14 Large-scale indicator indices of ocean climate change and impacts on salmon......Page 458
16.15 Management issues and responses to changes in ocean climate......Page 461
References......Page 462
17.1 Introduction......Page 475
17.2 Ecological research that contributes to conservation......Page 478
17.3 Environment, genetics, and changes in life-history......Page 481
17.5 Multidisciplinary science......Page 483
References......Page 484
Index......Page 487