Chapter 8 Freshwater Ecosystems and Fisheries

Lead Authors Frederick J.Wrona,Terry D. Prowse, James D. Reist

Contributing Authors Richard Beamish, John J. Gibson, John Hobbie, Erik Jeppesen, Jackie King, Guenter Koeck, Atte Korhola, Lucie Lévesque, Robie Macdonald, Michael Power,Vladimir Skvortsov,Warwick Vincent

Consulting Authors Robert Clark, Brian Dempson, David Lean, Hannu Lehtonen, Sofia Perin, Richard Pienitz, Milla Rautio, John Smol, Ross Tallman,Alexander Zhulidov

Contents

Summary ...... 354 8.5. Climate change effects on fish, fisheries, and aquatic 8.1. Introduction ...... 354 wildlife ...... 393 8.1.1. Challenges in projecting freshwater hydrologic and ecosystem 8.5.1. Information required to project responses of arctic fish ...... 393 responses ...... 354 8.5.1.1. Fish and climate parameters ...... 394 8.1.2. Quantifying impacts and likelihood ...... 356 8.5.1.2. Ecosystems, habitat, and fish: climate change in the 8.1.3. Chapter structure ...... 356 context of multiple stressors ...... 400 8.2. Freshwater ecosystems in the Arctic ...... 356 8.5.1.3. Effects of climate-induced changes on physical habitat .402 8.2.1. General features of the Arctic relevant to freshwater 8.5.1.4. Issues at the level of fish populations ...... 403 ecosystems ...... 356 8.5.2.Approaches to projecting climate change effects on arctic fish 8.2.2. Freshwater inputs into arctic aquatic ecosystems ...... 357 populations...... 403 8.2.3. Structure and function of arctic freshwater ecosystems ...... 358 8.5.2.1. Physiological approaches ...... 404 8.2.3.1. Rivers and streams, deltas, and estuaries ...... 358 8.5.2.2. Empirical approaches ...... 404 8.2.3.2. Lakes, ponds, and wetlands ...... 361 8.5.2.3. Distributional approaches ...... 405 8.3. Historical changes in freshwater ecosystems ...... 365 8.5.3. Climate change effects on arctic freshwater fish populations . .406 8.3.1. Ecosystem memory of climate change ...... 365 8.5.3.1. Region 1: European percids ...... 406 8.3.1.1. Lentic archives ...... 365 8.5.3.2. Region 2: Fishes in Siberian rivers ...... 406 8.3.1.2. Lotic archives ...... 366 8.5.3.3. Region 3:Alaskan game fish ...... 407 8.3.1.3.Terrestrial and wetland archives ...... 366 8.5.3.4. Region 4: Northern Québec and salmonid 8.3.2. Recent warming: climate change and freshwater ecosystem and pike populations ...... 407 response during the Holocene ...... 366 8.5.4. Effects of climate change on arctic anadromous fish ...... 408 8.3.2.1. Region 1:Arctic Europe, eastern , the Russian 8.5.5. Impacts on arctic freshwater and anadromous fisheries ...... 410 European North, and the North Atlantic ...... 367 8.5.5.1. Nature of fisheries in arctic freshwaters ...... 410 8.3.2.2. Region 2: Siberia ...... 368 8.5.5.2. Impacts on quantity and availability of fish ...... 411 8.3.2.3. Region 3: Chukotka, the Bering Sea,Alaska, and western 8.5.5.3. Impacts on quality of fish ...... 412 Arctic ...... 369 8.5.5.4. Impacts on access to and success of fisheries ...... 413 8.3.2.4. Region 4: Northeastern Canada, Labrador Sea, Davis 8.5.5.5. Impacts on specific fishery sectors ...... 416 Strait, and West Greenland ...... 371 8.5.5.6. Impacts on aquaculture ...... 417 8.3.3. Climate change and freshwater ecosystem response during the 8.5.6. Impacts on aquatic birds and mammals ...... 417 Industrial Period ...... 371 8.6. Ultraviolet radiation effects on freshwater ecosystems . . . .419 8.4. Climate change effects ...... 372 8.6.1. Climate effects on underwater ultraviolet radiation exposure . .419 8.4.1. Broad-scale effects on freshwater systems ...... 372 8.6.2. Ultraviolet radiation effects on aquatic biota and ecosystems . .420 8.4.2. Effects on hydro-ecology of contributing basins ...... 376 8.6.3. Impacts on physical and chemical attributes ...... 423 8.4.3. Effects on general hydro-ecology ...... 379 8.6.4. Impacts on