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Keith Brander ICES/GLOBEC Coordinator

Past and future impacts of climate change on North Atlantic cod. Artist: Glynn Gorick. Keith Brander ICES/GLOBEC Coordinator. Global climate change and regional impacts Schrum. IPCC provides Climate Change scenarios from GCMs

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Keith Brander ICES/GLOBEC Coordinator

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  1. Past and future impacts of climate changeon North Atlantic cod Artist: Glynn Gorick Keith BranderICES/GLOBEC Coordinator Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  2. Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  3. Global climate change and regional impactsSchrum • IPCC provides Climate Change scenarios from GCMs • Downscale GCMs output for regional models of hydrodynamics (and biota) • Aim of WKCFCC - 20-50 year projections of fisheries productivity Lower trophic level dynamics Future scenario hydrodynamics GCM low resolution Regional Model high resolution Assumptions on nutrient and biotic fluxes Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  4. Conclusions from WKCFCC • IPCC 2007 model results differ from observations for the current climate, especially at regional level • GCMs do not reproduce the two major modes of N Atlantic variability over the last century (AMO, NAO) • global and regional climate models are not yet adequate for impact studies on the marine ecosystem • models that assimilate recent climate data (and include the decadal modes) show useful forecasting skill, at least over periods of a few years Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  5. What do ecosystem models require from climate models (resolution, error margins)? • skilful in the region of interest - validity and skill tested with a present day reference simulation • validation exercise needs to be performed regionally for the following variables: • winds and air pressure (i.e. the correct location of the mean large-scale pressure systems is the single most important requirement) • short wave radiation (clouds) and air temperature • humidity • precipitation and runoff • temperature and salinity in the ocean. Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  6. skilful not only for the average climate signal but also for the seasonal signal, the inter-annual variability and the diurnal variability, since variability on all of these different timescales can be an important drivers of biological processes • regional bias and model errors in dynamically active (nonlinear processes) variables (temperature gradients, wind fields) need to be clearly smaller than the climate change signal, while error margins need to be given with reference to the present day climate simulations. Larger error margins have to be corrected and specific corrections have to be developed. Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  7. Variables needed to force the regional ocean physical-biological models are: • wind fields (10 m) • sea level pressure • sea surface • air temperature • dew point temperature (humidity) • short wave radiation • cloud cover • atmospheric long-wave radiation • runoff • sea ice Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  8. It might also be necessary to correct for resolution bias in the global models • Oceanic data requirements are: • initial and boundary conditions in the temperature, salinity and sea level • temporal resolution needed is 3h-6h for the atmosphere and daily to weekly for the oceanic parameters. Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  9. Back to biology and history Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  10. 80-200 pre LGM Where did cod survive during the last ice age? Estimated time (thousand yrs) since population sub-division 20-30 post LGM? 10-50 post LGM? 50-85 pre LGM 75-150 pre LGM • Bigg, G.R., Cunningham, C. W., Ottersen, G. Pogson, G.H., Wadley, M.R., and Williamson, P. 2008. Ice-age survival of Atlantic cod: agreement between palaeoecology models and genetics Proc Roy Soc B (2008) 275, 163-72 Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  11. Cod survived the last ice-age on both sides of the Atlantic, but were probably limited to European waters in the penultimate ice age, around 150k yr ago Cod populations seem able to survive even large changes in climate (However they also respond very rapidly to change in climate) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  12. Vendsyssel Limfjord E. Jutland NE Sjælland Bornholm NW Funen Map: K. Rosenlund • Temperature was 2 to 3 oC higher • Salinity was up to 4 psu higher • Water level was much higher (see map) • Atlantic cod were common, together with southern species Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  13. Climate is one of many pressures Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  14. From http://www.ipcc.ch/pdf/presentations/wg1-report-2007-02.pdf Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  15. Climate was a big issue in the 1930s. Published in1939 Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  16. Cod ”invasion” 1908- 1912 1917 1919 1922 1927 1929 1931 1937 Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009 (Jensen, 1939)

  17. Potential spawning areas, larval drift and migration Spawning area Eggs and larvae Juveniles Adults (> 4-6 yrs) 1950s 1960s 1990s: No spawning off SE and SW Greenland (modified after Wieland and Storr-Paulsen 2005) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009 (Logeman et al. 2004)

  18. Atlantic cod catch at Greenland Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  19. Changes in distribution and abundance of fish species off West Greenland during the period of warming from 1920 onwards.Prepared by Brander (2003) based on Saemundsson (1937) and Jensen (1939). Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  20. Changes in distribution and abundance of fish species off Iceland during the period of warming from 1920 onwards.Prepared by Brander (2003) based on Saemundsson (1937) and Jensen (1939). Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  21. Another multidecadal effect Changes in spawning areas of Arcto-Norwegian cod in response to multidecadal climate oscillations Sundby and Nakken (2008) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  22. Conclusion: • Fish (and other marine species) can expand and contract their ranges and populations very rapidly • The past may provide an analogue for the future. As Greenland warms cod is expected to extend its range and become more abundant Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  23. Annual, decadal and multidecadal variability Relations between spatial and temporal scalesSundby Period (years) AMO ~60 år NAO ~10 år Length scale (km) ~1 år Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009 Kilde: PINRO, Murmansk

  24. The NAO governs windfields (and hence temperature, cloud, inflows). It affects plankton, fish recruitment and many other marine and terrestrial systems. Redsymbols indicate strength and sign of effect of NAO on cod recruitment Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  25. Inflow of warm Atlantic water Outflow of cold Arctic water Inverse winter temperature fluctuations between Greenland and Denmark were already known in the 18th century Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009 Sundby and Drinkwater (2007)

  26. Effects of reduced Atlantic inflow: “.. in the Norwegian Sea the Polar Front, which separates Atlantic and Arctic waters, typically lies a few hundred km north of the Faroe Islands and reduced inflow would be likely to move the front closer to or even onto the Faroe Shelf. If such a shift takes place a cooling of the order of 5oC would possibly occur in the areas affected.” From ACIA report 2005 Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  27. Inflows are not just about heat transport Average PP in spring north of Iceland(borrowed from Olafur Astthorsson)

  28. Need to know: How will the THC (MOC) change? What are the consequences of change in the THC for the position and strength of ocean fronts, ocean current patterns and vertical stratification? This has consequences for inflows, position of the polar front, plankton production, fish distribution (which are only partly to do with temperature) From ACIA report 2005 Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  29. Back to processes and fish Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  30. What does climate do to fish? Define ”bioclimate envelopes” based on temperature and other factors. Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  31. Growth performance of cod • Small cod (>32g) grow quickly and have a high optimal temp • The curve (for fish >32g) is domed and pretty flat over most of the range • Effects of temperature variability are greatest on small fish and at low (<5oC) temperature. • Food limitation alters things, but only seems to happen sometimes • Wild growth is lower because of higher activity levels, sex and sometimes food limitation etc. Data from Bjornsson and Steinarsson (2002) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  32. Sensitivity of cod growth rate to temperature changes with size (results from experiments with satiation feeding) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  33. Reproductive performance of cod Less sensitive range Sensitive range Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  34. Dynamics of early life is critical and sensitive >99.99% mortality in first few weeks of life Many millions of eggs produced per female Image: Glynn Gorick for ‘Cod and Climate’ (ICES) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  35. Key parameters for spawning Water depth <500m ICES empirical data for 23 cod stocks (Brander 1994, 2005) Image: Glynn Gorick for ‘Cod and Climate’ (ICES) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  36. Key parameters for spawning Water depth <500m Time of spawning Feb -June ICES empirical data for 23 cod stocks (Brander 1994, 2005) Image: Glynn Gorick for ‘Cod and Climate’ (ICES) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  37. Key parameters for spawning Water depth <500m Time of spawning Feb -June 0 - 9°C (3 - 7 °C) ICES empirical data for 23 cod stocks (Brander 1994, 2005) Egg survival data from Pepin (1997) Temperature Image: Glynn Gorick for ‘Cod and Climate’ (ICES) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  38. 4°C 8°C 0,8 12°C Growth rate (mm d-1) 16°C Crit. zooplankton biomass mgC m-3 0,6 20°C 0,4 25 20 0,2 15 Temperature (°C) 0,0 2 5 10 20 50 100 200 Total zooplankton biomass mgC m-3 10 5 0 4 8 12 16 20 Trade off: fast growth reduces predation risk, but increases risk of starvation Growth (and survival) of larvae depends on temperature and food High temperature  high metabolism  high food requirement Higher turbulence levels Higher zooplankton biomass requirements Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  39. Regional examples:BalticNorth SeaCanadian cod stocsk Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  40. In the Baltic low O2 and salinity limits cod reproduction (Plikshs et al. 1993; Wieland et al. 1994) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  41. Variability in Cod Reproductive Volume Reproduction requires S > 11 psu O2 > 2 ml/l Plikshs et al. 1993 MacKenzie et al. 2000 Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  42. Reproductive Volume depends on hydrographic and climatic processes Such as inflows from the North Sea Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  43. Distribution of cod contracts when salinity is low Aro & Sjöblom 1983; MacKenzie et al. 2000; Köster et al. 2005 High salinity (frequent inflows) Low salinity (few inflows) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  44. cannibalism on juveniles food competition predation on juvenile herring predation on sprat continuous process, modulated by habitat overlap (S, T, O2) predation on sprat & cod eggs cannibalism on eggs food competition Complexity of intra- and inter-species interactions: cod and clupeids in the Baltic Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  45. What will happen to cod as the Baltic gets warmer and fresher? • Will there be adaptation? (how did they survive 7000 years ago) • Period in life which is sensitive to low salinity is very short • Depends on fisheries management (in short to medium term) Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  46. Effects of fishing and climate interact Risk that cod will disappear from the Baltic Climate Fishing Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  47. North Sea cod distribution has changedThere are (at least) five hypotheses to explain this Engelhard, South, Pinnegar • Warming ‘drives’ cod further north (tagging does not support this) • Temperature reduces recruitment and/or survival in the south • Fishing pressure is higher in the south • Winds alter larval drift and adults then remain in north • Different substocks respond differently to local climate and fishing pressure variability Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  48. The data 1913-1980: cpue steam and motor otter trawlers 1982-present: cpue motor otter trawlers Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  49. Decades 1920s–2000s: distribution cod cpue(normalised by year) 20s 30s 40s 50s 60s 70s 80s 90s 00s Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

  50. Changed centre of gravity of cod distribution • Latitude • Longitude • SST anomaly • Major cod distribution shifts, but not obviously linked to temperature, changes fishing, winds etc. • Mean population depth increases as annual mean temperature increases, but individual fish do not show clear temperature response Applying IPCC-class models of global warming to fisheries prediction - Princeton June 2009

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