NCCARF Climate change effects on fisheries: implications for management Nick Caputi Alan Pearce & Rod Lenanton December 2009
Overview 1. Overall environmental trends 2. Environmental effect on fisheries (recruitment, size at maturity, etc) 3. Historic trend of these environmental variables 4. Implications Stock assessment management 5. Future climate trends 6. Future climate change effects on fisheries
Key environmental trends (a) increasing frequency of ENSO events; (b) more years with weaker Leeuwin Currents; (c) increase in water temperature off lower west coast (autumn-winter) (d) increase in salinity with large inter-annual fluctuations (e) changing frequency & location of storms (westerly winds, rainfall) lower west coast (f) change in frequency of cyclones (& summer rainfall) affecting north-west of WA
Environmental databases (Alan Pearce) 1. SOI /Indian Ocean Dipole (monthly) 2. Fremantle sea level (monthly) National Tidal Centre 3. Temperature/salinity puerulus sites (monthly) DoF commercial lobster monitoring (monthly Nov-June) DoF Rottnest station - CSIRO 4. Reynolds Satellite SST (monthly 1 o block) CSIRO 5. ChlA (monthly 1 o block) CSIRO 6. Wind data Automatic Weather Stations (12) (minute) - BoM NCEP: large scale winds 7. Temp logger Puerulus sites (hourly) - DoF Albany/Esperance (daily (1980-92) Exmouth (hourly 1997-00) - DoF Jurien/Ningaloo/Rowley Shoals (hourly) DEC 8. Wave data - DPI
Rate of warming ( C/year) 1951 2004 (Pearce & Feng, 2007) 30 20 10 0 10 20 30 40 Western Australia o C/yr 0.05 0.04 0.03 0.02 0.01 0 0.01 0.02 0.03 0.04 0.05 50 20 30 40 50 60 70 80 90 100 110 120 130
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 et al. 2009
Leeuwin Current (Warm low-nutrient waters flowing south)
Frequency of ENSO events 8 events in 18 years (1991-2008) 1 in 2 years 5 events in 20 years (1971-1990) 1 in 4 years Cause? Climate shift at decadal level (Pacific Decadal Oscillation) Climate change
Modelled volume transport of Leeuwin Current at 32S (off Perth) Southward Ming Feng
Case studies - examples 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)
Female with tarspot (sperm) & eggs Phyllosoma larvae Life History Stages Migrating white & non migrating red Puerulus
Standardized Migrating Whites Mean Carapace Length 90.00 88.00 86.00 84.00 Fremantle 82.00 All Locations 80.00 CL (mm) 78.00 76.00 Dongara 74.00 74/75 76/77 78/79 80/81 82/83 84/85 86/87 88/89 90/91 92/93 94/95 96/97 98/99 00/01 02/03 04/05 Season Caputi et al. in press
'Whites' carapace length and Water temperature 85 83/84 84 84/85 82/83 <87/88 '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 92/93 01/02 >88/89 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 et al. in press
Scallops (Amusium balloti)
Scallop catches v. El Nino events Shark Bay Landed catch (t whole wt) 25000 20000 15000 10000 5000 0 * * El Nino event previous year * * * * * * * * * 85 87 89 91 93 95 97 99 01 03 05 07 Year * Abrolhos Islands Landed catch (t whole wt) 25000 20000 15000 10000 5000 0 * El Nino event previous year * * * * * * * * * * 85 87 89 91 93 95 97 99 01 03 05 07 Year * Lenanton, Caputi, Kangas 2009
Pearl oyster piggyback spat (0+ and 1+) Hart & Joll 2006
0+ Spat (per 1000 shell) 0+ Spat (per 1000 shell) 30 25 20 15 10 5 0 8 7 6 5 4 3 A 0 100 200 300 400 500 600 700 800 900 B (05) 2005 Settlement r 2 = 0.91 (03) (06) (07) (02) (05) (04) (01) Bidyadanga Rainfall (Nov-Apr) mm (03) r 2 = 0.69 (06) (07) (04) (05) (02) (01) 300 400 500 600 700 800 900 Bidyadanga Rainfall (Nov-Apr) mm Pearl oyster 0+ settlement vs rainfall (Nov to April) at Bidyadanga Hart et al. in prep.
Rainfall trends (Nov-April) Bidyadanga 1400 1200 C 3 yr mean 1000 800 600 400 Nov - Apr Rainfall (mm) 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 200 0 2005 Rainfall 2000 2010 Hart et al. in prep.
Tailor: Recruits 0+ (Feb-Apr) v. Salinity previous year Point Walter juvenile catch rate (no./person/hour) 4 3 2 1 0 01 02 03 00 98 04 06 99 07 08 96 05 97 95 35.6 35.8 36.0 36.2 36.4 36.6 Ayvazian et al. Salinity (Nov-Jun) (lagged 1 year)
Implications for stock assessment (Rock lobster case study) Biological parameters generally assumed fixed Climate change trends of biological parameters Size of migrating (to deepwater) lobsters smaller More lobsters in deep water Size of maturity smaller Change in growth curve Reduced recruitment Abundance trends/prediction important
Management implications Changes in abundance (+ve or ve) Adjust fishing effort and/or catch quota Changes in biological parameters (eg growth) changes in minimum/maximum size etc? Change in spatial distribution of species relative to management boundaries winners and losers? historic shares?
SHARK BAY Rock lobster 26 S WESTERN AUSTRALIA fishery ABROLHOS IS LANDS PORT GREGORY DONGARA NORTH COASTAL - 3 Fishing zones - 9 Collector sites 30 S SOUTH COASTAL JUR IE N LA NC E LIN ALKIMOS FREMANTLE INDIAN OCEAN WARNBRO 34 S CAPE MENTELLE 113 E 116 E
Future climate trends/research Poloczanska et al. (2007) CSIRO Mk3.5 model Waters around Australia will warm 1-2 o C (2030s) & 2-3 o C (2070s) Westerly winds in southern Australian waters weaken Higher frequency of ENSO events? WA marine climate change (WAMSI Node 2) Indian Ocean, Leeuwin Current, coastal site Indian Ocean Climate Initiative (IOCI) Storm rainfall decline (south-west) Increase in cyclones/rainfall (north-west)
Research Findings Caputi, N., Pearce, A., Lenanton, R. (in prep.). Fisheries-dependent data and climate. WAMSI. report Caputi, N., de Lestang, S., Feng, M., Pearce, A. (2009). Seasonal variation in the long-term warming trend in water temperature off the Western Australian coast. Marine and Freshwater Research 60: 129-139 Caputi, N., Melville-Smith, R., de Lestang,S., Feng,M., Pearce, A. (in press). The effect of climate change on the western rock lobster fishery. Can.J. Fish.Aquat. Sci. Lenanton, R, N. Caputi, M. Kangas, M. Craine (2009). The influence of the Leeuwin Current on economically important fish and invertebrates off temperate Western Australia. J. Royal Soc. WA 92: 111-127