Distribution mapping and health assessment of honeycomb worm, Sabellaria alveolata, reefs on Heysham Flat, Lancashire Report to the North Western Inshore Fisheries and Conservation Authority January 2014 Sian Egerton, c/o Cumbria Wildlife Trust Email: [email protected] Alternative email: [email protected] Sabellaria alveolata: distribution mapping and health assessment Report to NWIFCA Contents Figures & tables ................................................................................................................................ 3 Figures ...................................................................................................................................... 3 Tables ........................................................................................................................................ 4 1 Acknowledgements .................................................................................................................... 5 2 Introduction ................................................................................................................................ 6 2.1 Background ........................................................................................................................ 6 2.1.1 Distribution ........................................................................................................................ 6 2.1.2 Environmental requirements ............................................................................................. 7 2.1.3 Population dynamics ......................................................................................................... 7 2.1.4 Associated biodiversity ..................................................................................................... 7 2.1.5 Competition with the blue mussel, Mytilus edulis .............................................................. 8 2.1.6 Conservation status of Sabellaria alveolata ...................................................................... 8 2.2 Project aims & objectives .................................................................................................... 9 2.3 Previous surveys ................................................................................................................ 9 3 Survey location .......................................................................................................................... 9 4 Field surveys ........................................................................................................................... 10 4.1 Survey organisation .......................................................................................................... 10 4.1.1 Access permissions ........................................................................................................ 10 4.1.2 Licenses ......................................................................................................................... 10 4.1.3 Site of Special Scientific Interest (SSSI) consent ............................................................ 10 4.1.4 Dates, tides & surveying hours ....................................................................................... 10 4.1.5 Surveyors ....................................................................................................................... 11 4.2 Methodology ..................................................................................................................... 11 4.3 Data analysis .................................................................................................................... 12 4.3.1 Statistical analysis .......................................................................................................... 12 4.3.2 Mapping data .................................................................................................................. 13 5 Results .................................................................................................................................... 13 5.1 Sabellaria alveolata distribution ........................................................................................ 14 5.2 Health and formation of Sabellaria alveolata ..................................................................... 17 5.3 Mytilus edulis distribution .................................................................................................. 22 5.4 Biodiversity ....................................................................................................................... 25 5.5 Summary of results ........................................................................................................... 26 6 Discussion ............................................................................................................................... 26 2 Sabellaria alveolata: distribution mapping and health assessment Report to NWIFCA 6.1 Sabellaria alveolata distribution ........................................................................................ 27 6.2 Health & formation of honeycomb worm reef .................................................................... 27 6.3 Mytilus edulis distribution .................................................................................................. 28 6.4 Biodiversity ....................................................................................................................... 29 7 Conclusion ............................................................................................................................... 30 8 Future research & recommendations ....................................................................................... 30 9 References .............................................................................................................................. 31 10 Appendices .............................................................................................................................. 35 10.1 Appendix I – A guide to the classification of Sabellaria alveolata ...................................... 35 10.2 Appendix II – Outline of waypoints covered during each survey ....................................... 36 10.3 Appendix III – Sabellaria alveolata raw data ..................................................................... 37 10.4 Appendix IV –Mytilus edulis and substrate raw data ......................................................... 51 Figures & tables Figures Figure 1. Distribution of Sabellaria alveolata in UK waters ................................................................ 6 Figure 2. Location of Heysham Flat survey site............................................................................... 10 Figure 3. Percentage cover of Sabellaria alveolata on Heysham Flat ............................................. 15 Figure 4. Presence of Sabellaria alveolata on Heysham Flat .......................................................... 16 Figure 5. Distribution of formation types (patchy, hummock, reef and sheet) of Sabellaria alveolata at Heysham Flat .............................................................................................................................. 18 Figure 6. Distribution of health types (crisp aperture, worn aperture, newly settled and dead) of Sabellaria alveolata at Heysham Flat .............................................................................................. 19 Figure 7. Patchy formation of Sabellaria alveolata colonies ............................................................ 20 Figure 8. Typical hummock formations of Sabellaria alveolata ........................................................ 20 Figure 9. The health of Sabellaria alveolata worms associated with different reef formations ......... 21 Figure 10. Sabellaria alveolata colonies in reef formation ............................................................... 21 Figure 11. Percentage area of adult blue mussels, Mytilus edulis, in quadrats surveyed on Heysham Flat between 2011 and 2013........................................................................................................... 22 Figure 12. Percentage area of under-size blue mussels, Mytilus edulis, in quadrats surveyed on Heysham Flat between 2011 and 2013 ........................................................................................... 23 Figure 13. Percentage area covered by under-size and adult blue mussels, Mytilus edulis, on Heysham Flat ................................................................................................................................. 24 Figure 14. Examples of the species recorded in close proximity to Sabellaria alveolata colonies .... 25 Figure 15. Correlation between species richness and Sabellaria alveolata percentage cover ......... 26 3 Sabellaria alveolata: distribution mapping and health assessment Report to NWIFCA Figure 16. Cyclical recruitment of Sabellaria alveolata and Mytilus edulis to Heysham Flat skear between 2011 and 2013 ................................................................................................................. 29 Tables Table 1. Survey dates and corresponding daylight hours and tide times. ........................................ 11 Table 2. Descriptions of different formation types used to categorise Sabellaria alveolata colonies 12 Table 3. Number of waypoints surveyed in 2011, 2012 and 2013 at Heysham Flat, Lancashire ..... 14 Table 4. Percentage cover of Sabellaria