G. Nolan 1, K.Lyons 1, S.Fennell 1, T. Mc Grath 1, D.Guihen 2, C.Cusack 1, C. Lynam 3 G. Nolan 1, K.Lyons 1, S.Fennell 1, T. Mc Grath 1, D.Guihen 2, C.Cusack 1, C. Lynam 3 Variability in the physical structure, ocean chemistry, plankton ecology and commercial fish species of the seas surrounding Ireland between 1997 and 2010 ICES/NAFO Decadal Symposium, Santander 11 th May 2011

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Water mass overview

Biogeographical provinces: Niall Mc Ginty et al., (Poster 78) May 2011

Trends in sea surface temperature ( )  Recent intense warming in the NE Atlantic attributed in part to the AMO (Atlantic Multidecadal Oscillation), and in part to global warming.  Sub-polar gyre cooled over the period, consistent with predominantly positive NAO Local temperature anomalies extracted from HadSST2. Malin head data is overlain in red ( Note apparent 60 year cycle in N. Atlantic)

Cannaby H, Husrevoglu YS (2009) The influence of low-frequency variability and long-term trends in North Atlantic sea surface temperature on Irish waters. ICES J Mar Sci:fsp062

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AVHRR: SST anomaly from mean

Porcupine Bank Station depth = 3000m SAIW 2010 MEDW 2007

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Development of suitable growth conditions in Spring using SST as an indicator 1959 – 2005 (47 years daily SST data). Timing of Spring in Julian Days 1: Interannual variations on the date SST reaches 10 C 2: General Trend in coastal waters that it is arriving earlier 3: Abiotic conditions important in spring (water column structure and nutrient availability) 15 April 05 June Spring Bloom timing Winter: Land vegetation greening occurred 10 days earlier than the average over the past three decades (Geophs. Res. Lett. 2008) Maignan et al.

Phytoplankton colour and HAB species The percentage occurrence of Karenia mikimotoi during the winter months has increased since 2000 Total annual abundance of harmful and toxic species varies greatly between years An increase in phytoplankton biomass is evident in the northern Celtic Sea, based on Continuous Plankton Recorder (CPR) data, since 2000

Zooplankton changes: Beaugrand view of whole region Specific look at warm water species in Irish waters (on the increase) Warm >>>>>>>>>> cold The abundance of a common warm water species (Calanus helgolandicus) has increased to the southeast of Ireland mean abundance in Celtic Sea : AnnualMarch p < 0.05

Poor cod distributions 2003/4 vs 2006/7 (possible indicator species) Poor cod and lesser spotted dogfish have increased to the north of Ireland and decreased to the south and are suitable candidate climate indicator species

Decline in cold-water species of fish and increase in warm- water species (Kendall tau plot) eg. Boarfish Fishery effects must be considered and long-term data is required to detect such change Red= expected distribution Blue= actual

Pipefishes (Syngnthidae) – related to seahorses A symptom of major ecosystem changes? Possibly linked to SST rises? Largely absent from samples Increase in catch in 2003, 2004, 2005

Migratory fish species Salmon – declining marine survival since the 1970s Sea trout – stock collapse in 1980s, with adult returns still at a low level

Nutrient analysis: water mass definition

May 2011 Higher surface nutrients in more recent cruises AABW signal Higher phosphate values on WOCE cruises

Conclusions Warming trend with AMO signal apparent at Malin Head LSW (freshened between 2004 and 2009 and then increased salinity in 2010 and 2011) Changes in temperature are mirrored in biological data sets 4. Increases in the annual numerical abundance of diatoms and dinoflagellates are evident in all coastal regions since Warm water fish species more prevalent Decline in migratory fish returns Some differences in nutrient concentrations when comparing WOCE data with data