Ocean fronts as an indicator of marine animals: expediting site selection and survey for offshore renewables

Transcription

1 Ocean fronts as an indicator of marine animals: expediting site selection and survey for offshore renewables Peter Miller and David Sims 1 1 MBA

2 Oceanic fronts for pelagic diversity Detecting ocean fronts using EO data UK project on Marine Protected Areas Application to offshore renewable energy Marine animal case studies: Basking sharks vs. fronts Seabirds vs. fronts Acknowledgements:

3 Satellite detection of oceanic fronts 26 Jun :37 27 Jun :58

4 Composite front maps: revealing important fronts X X F mean F persist F comp Mean gradient P front F prox Persistence Advection / proximity Miller, P.I., (2009) Composite front maps for improved visibility of dynamic oceanic fronts on cloudy AVHRR and SeaWiFS data, Journal of Marine Systems.

5 Advantages of front detection F comp SST Does not blur dynamic features. Highlights persistent or strong gradient fronts. Miller, P.I., (2009) Composite front maps for improved visibility of dynamic oceanic fronts on cloudy AVHRR and SeaWiFS data, Journal of Marine Systems.

6 Ocean fronts vs marine megafauna Firth of Clyde, Scotland 55.5 N Front Basking shark track 55.0 N 5.5 W 5.0 W Priede, I.G. & Miller, P.I. (2009) A basking shark tracked by satellite with simultaneous remote sensing: reveals orientation to a thermal front. Fisheries Research, 95(2-3), Also many pelagic fish distributions are related to fronts

7 Seasonal frequent front maps Percentage of time for which a strong front was observed, over 10 years Summer % Fronts may be used as a proxy for pelagic biodiversity Technology used by Defra to help define Marine Protected Areas Techniques can be applied worldwide

8 Seasonal frequent front maps Percentage of time a strong front was observed at each location Winter Spring % Strong seasonal variability Summer Autumn

9 Areas of Pelagic Ecological Importance % Front maps were used to prioritise candidate MPAs: 10 out of 46 offshore MPAs. Now being used to model distribution of cetaceans for Countryside Council of Summer Wales Frequent fronts

10 Validation of frequent front maps Front map compares well with in situ and model analyses of front locations. Summer frequent front map compared with fronts predicted by a numerical model based on tidal currents and bathymetry (dashed lines, Pingree and Griffiths, 1978). FF=Flamborough front, UF=Ushant front, CSF=Celtic Sea front. FF CSF Miller, P.I. & Christodoulou, S. (accepted) Frequent locations of ocean fronts as an indicator of pelagic diversity: application to marine protected areas and renewables. Marine Policy. UF %

11 Ocean fronts: from spaghetti to synoptic chart May 2008 Weak Key Warm Cold Strong May 2008 Miller, P.I., (in preparation), A line clustering algorithm with application to simplifying ocean front maps derived from satellite data, Remote Sensing of Environment.

12 Application to offshore renewables Front techniques could be applied to characterise the proposed sites of marine renewable installations. Enable a cost-effective initial comparison of alternative sites in terms of potential impact on marine animals (and fishermen), and expedite planning process. Contribute to the environmental impact assessment, by estimating the likely abundance and distribution of key species known to inhabit the area. During construction, use near-real time EO data to advise on operation times to minimise acoustic impacts on marine mammals. Witt, M.J., et al. including Miller, P.I. (2012) Assessing wave energy effects on biodiversity: the Wave Hub experience. Phil. Trans. Royal Soc. A (IF 2.5)

13 Basking shark track vs. synoptic fronts Weak Key Warm Cold Strong 24 Aug. 15 Oct Acknowledgements to Prof David Sims and his shark-tagging team at MBA, Plymouth

14 Gannets tracked using GPS loggers 5 Gannets tracked 17 to 21 Jun. 2006

15 Gannets tracked using GPS loggers Key Weak Warm Cold Strong Sigma 4.0 T-high 0.5

16 Studying marine animal use of fronts Ongoing collaborations to gain evidence on: Basking sharks; Cetaceans; Seals; Turtles; Fish and fishing effort; Seabirds: Kittiwakes, Gannets, Albatross, Shearwaters, Fulmars Oppel, S., et al. including Miller, P.I. (in press) Comparison of five modelling techniques to predict the spatial distribution and abundance of seabirds. Biological Conservation PhD project on ocean front metrics for improving understanding of marine animals.

17 Ocean front metrics Front density Front distance May 2008 Weak Key Warm Cold Strong May 2008 Low High Low High

18 Higher resolution ocean colour fronts Thermal fronts Aug MERIS 300m chl-a fronts Aug Higher resolution ocean colour maps detect fronts closer to the coast. Colour may indicate physical features even when no thermal front.

19 Conclusions on fronts for renewables Defra have used oceanic fronts as a proxy for pelagic biodiversity, to guide the siting of 10 out of 46 offshore MPAs. Ocean front statistics could be applied to expedite site selection for marine renewable installations, while minimising potential impact on marine animals. May also assist EIA and construction procedures. PML is gathering further evidence on the importance of satellite-detected fronts to marine animals: Basking shark feeding behaviour; Seabirds, cetaceans, seals, fish, etc. Peter Miller - pim@pml.ac.uk NOC Association stand