Warming trends of ocean temperatures off the WA coast and implications for fisheries Nick Caputi Alan Pearce, Rod Lenanton, Ming Feng
Overview WAMSI 4.2.3: Fisheries-dependent data and climate change (Caputi, Pearce, Lenanton) WAMSI 2.2: Leeuwin Current (Feng) Marine heatwave summer 2010/11 (Pearce, Jackson, Lenanton, Feng)
Climate change effect on fisheries 1. Overall environmental trends 2. Environmental effect on fisheries (recruitment, size at maturity, etc) 3. Historic trend of environmental variables affecting fisheries (space-time) 4. Implications Stock assessment and management 5. Future climate trends 6. Future climate change effects on fisheries
Rate of warming ( C/year) 1951 2004 (Pearce & Feng, 2007)
Rate of change of water temperature Puerulus sites (Dongara/Jurien) Commercial monitoring 0-36 m Dongara/Jurien Commercial monitoring 0-36 m Lancelin/Fremantle Environmental monitoring 0-50 m Rottnest 0.04 0.03 Rate of Change ( o C/ year) 0.02 0.01 0-0.01-0.02 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Caputi, de Lestang, Feng, Pearce 2009
SST increase per year HadISST (1970-2006) by M. Feng in Caputi et al. 2009
Case studies environmental factors affecting fisheries 1. Western rock lobster 2. Prawns 3. Scallops 4. Blue swimmer crabs 5. Pearl oysters 6. Tailor 7. Dhufish 8. Whitebait 9. Marron
Western Rock Lobster (Panulirus cygnus)
Standardized Migrating Whites Mean Carapace Length Caputi, Melville-Smith, de Lestang, Pearce, Feng 2009
'Whites' carapace length and Water temperature 85 84 83/84 <87/88 84/85 82/83 'Whites' Carapace Length (mm) 83 82 81 80 79 95/96 81/82 85/86 76/77 79/80 88/89 80/81 90/91 86/87 89/90 96/97 94/95 97/98 77/78 07/08 78/79 06/07 87/88 00/01 93/94 91/92 99/00 04/05 05/06 >88/89 92/93 01/02 02/03 78 98/99 77 08/09 09/10 10/11 07/08 03/04 20.80 21.00 21.20 21.40 21.60 21.80 22.00 22.20 22.40 Water temperature Feb-Jun Lag 3-5 years Caputi, Melville-Smith, de Lestang, Pearce, Feng 2009
Salinity ( ) 37.0 36.8 36.6 36.4 36.2 36.0 35.8 35.6 35.4 Dhufish v. Capes current (Dec-Feb) (+ve trend salinity/wind: 1983+) Weak current 92 89 83 90 Poor recruitment 88 85 95 2.5 3.0 3.5 4.0 4.5 5.0 5.5 86 02 Wind speed (m/s) Strong current 84 04 93 87 00 03 91,98 05 94 99 97 01 96 Good Recruitment North component Capes
Implications for stock assessment (Rock lobster case study) Biological parameters generally assumed fixed Climate change trends of biological parameters Size of migrating lobsters (to deepwater) smaller More lobsters in deep water Size of maturity smaller Reduced recruitment recent years prediction important
Management implications Change in abundance (+ve or ve) Adjust fishing effort and/or catch quota Change in spatial distribution of species relative to management boundaries winners and losers? historic shares? Changes in biological parameters (eg growth) changes in minimum/maximum size etc?
On annual cycle, temperature variations are dominantly balanced by Leeuwin advection & sea surface heat loss WAMSI 2.2: Monthly heat balance off southwest coast (ORCA025 model) Total advection Residual (mixing) Net heat flux January December Feng, Biastoch, Boning, Caputi, Meyers (2008)
Leeuwin advection & heat storage previous winter/spring determine Feb-Apr SST 2000, high SST due to strong Leeuwin advection & warm SST previous winter Opposite occurred for 1993 Feng, Biastoch, Boning, Caputi, Meyers (2008)
Reversal of multi-decadal trends since 1993 Western Pacific: Pohnpei Eastern Pacific: Christmas Sea level trend 1993-2008 Feng, McPhaden, Lee 2010
Marine Heatwave: SST anomalies >2C Nov 2010 Dec 2010 Jan 2011 >2C >3C Feb 2011 Mar 2011 Pearce & Feng in prep.
SST anomalies Dec 2010
SST anomalies Feb 2011 NCEP-CPC
NCEP-CPC Marine heatwave : Sea level anomalies Feb 2011: peak 2010/11 La Nina event
30 28 Summer temperatures (Reynolds) Ning ShBay Abr Rot Capes Alb Esp Ningaloo Temperature C 26 24 22 20 18 1982 1987 1992 1997 2002 2007 Year Abrolhos Capes Esperance Summer temperature anomalies (Reynolds) Ning ShBay Abr Rot Capes Alb Esp 3 Temperature anomaly C 2 1 0-1 -2 1982 1987 1992 1997 2002 2007 Year
Marine heatwave: Oceanographic and Biological effects Strong Leeuwin Current (strong La Nina) Multi-decadal strengthening trend of tropical Pacific climate since 1993; Strengthening trend of Indonesian Throughflow Increase trend in SST Mortality abalone, rock lobster, fish (late Feb - associated with calm conditions) Species range extension south juveniles/adults Future recruitment extension in 1-2 years larval movement (mud crabs?)
Future Research FRDC: Management implications of climate change effects on fisheries in WA (Fisheries & CSIRO) Downscaling climate change effects (extension of Node 2) Assessing effects on fisheries (risk assessment) Management implications WAMSI stage 2 Kimberley climate change theme Non Kimberley climate change proposal Indian Ocean Climate Initiative (IOCI) Storm rainfall decline (south-west) Increase in cyclones/rainfall (north-west) New proposal