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2. Revealing the reef: marine life settling on ex-HMS Scylla Keith Hiscock Last updated: 9 th March 2009 Including information from the Settling on Scylla project Get this presentation: www.marlin.ac.uk/learningzone/scylla

3. The presentation: How Scylla was before sinking on 27 March 2004. What could we expect: experience from other artificial reefs. The time-line of marine life settlement. How you can help maintain records from Scylla – and get involved in reporting marine life observations. (All with thanks to: Plymouth Sound BS-AC; MCS local group especially Amy Bugg; Sally Sharrock; Peter Messenger; University of Plymouth Diving Centre, Unicomarine for identification of samples, and many others for the diving, the marine life records and the use of images. And, of course, the National Marine Aquarium for putting Scylla on the seabed - right-way-up.)

4. 19 November 2003. Devonport

5. Inspection of existing fouling

6. Oysters, sponges, barnacles etc. on one of the propellers

7. 27 March 2004 www.national-aquarium.co.uk

8. Other UK artificial reefs: Poole Bay (See: Jensen, A.C. & Collins, K.J., 1995, The Poole Bay artificial reef project. Biologia Marina Mediterranea 2, 111-122.) Images courtesy of Antony Jensen

9. Other UK artificial reefs: Poole Bay (From: Jensen, A.C. & Collins, K.J., 1995, The Poole Bay artificial reef project. Biologia Marina Mediterranea 2, 111-122.)

10. Other UK artificial reefs: MV Robert at Lundy (sunk, January 1975, survey 1980) Starboard (horizontal) side: 192 taxa (species or species groups) sampled from 1.4 sq. m; 39 taxa by observation; 29 taxa in c. 1 sq. m of close-up photographs.

11. Other UK artificial reefs: local wrecks Persier

12. Scylla. In the first year: 1. a small numbers of potentially resident fish (poor cod) were attracted after about 10 days; 2. colonisation by barnacles, tube worms, Obelia hydroids and microbial slime occurred within about four weeks; 4. barnacles, tube worms and Obelia hydroids became common at about 6-7 weeks and are joined by Tubularia hydroids and, on shallow parts, brown filamentous algae; 5. by ten weeks after placement, the variety of organisms was significant and kelp, solitary sea squirts, anemones etc. had settled. 3. wandering species find the reef (spiny starfish, spiny spider crabs, long-spined sea scorpion etc.);

13. Poor cod

14. Colonisation by microbial slime, barnacles, tube worms and Obelia hydroids had occurred within about four weeks 23 April 2004 Barnacles, Balanus crenatus Tube worms, Pomatoceros triqueter 23 April 2004

15. 9 June 2004 Brown filamentous algae

16. 25 June 2004 Spiny starfish, Marthasterias glacialis

17. 30 July 2004 Keeled tube worms, Pomatoceros triqueter, saddle oysters, Heteranomia squamula etc.

18. Scylla. In the first year (continued): 8. by 30 weeks, juvenile queen scallops abundant over and in the vessel. Green urchins and common starfish now abundant and largish. 6. by 18 weeks, a wide variety of species including mass settlement of juvenile queen scallops, manydecorata anemones, extensive growths of Tubularia hydroids, variety of algae etc. Mussels settling. Tube worms and solitary sea squirts cover some surfaces. Algae abundant on upper surfaces; 7. by 24 weeks, green urchins and common starfish have settled in large numbers;

19. 30 July 2004 Queen scallops settle

20. 18 February 2005 Queen scallop, Aequipecten opercularis inside the vessel

21. 30 July 2004 Decorata anemone, Sagartia troglodytes decorata

22. 9 June 2004 Tubularia hydroid

23. 9 June 2004 Encrusting sea mat, ?Electra pilosa

24. 30 July 2004 Solitary sea squirts, Ciona intestinalis

25. 30 July 2004 Brown alga, Cutleria multifida

26. 30 July 2004 Filamentous red algae

27. 30 July 2004 Facelina bostoniensis and eggs 30 July 2004

28. 25 September 2004 By end of the summer: dense colonisation – but the urchins and starfish have settled

29. 10 November 2004 Mussels, Mytilus edulisImage: Sally Sharrock

30. Scylla. In the first year (continued) 9. green sea urchins and common starfish together with normal seasonal decline have removed algal growth and much barnacle and tube worm cover; By midwinter (40-48 weeks): 10. common starfish have removed mussels, barnacles and, no doubt, other species; 11. the reef looks bare; 12. plumose anemones are reproducing (by basal laceration) and are becoming visually dominant near the bow; 14. corkwing wrasse observed holding territory. 13. calcareous sponges have settled;

31. 18 February 2005 Green sea urchin Psammechinus miliaris

32. 18 February 2005 Common starfish, Asterias rubens

33. 18 February 2005 Cleaned by urchins & starfish

34. 18 February 2005 Plumose anemone, Metridium senile

35. 18 February 2005 Calcareous sponges, Leucosolenia botryoides & Sycon ciliatum

36. 18 February 2005 Colonisation on below-waterline black paint. Effective antifouling paint

37. 30 January 2005 Corkwing wrasse on the starboard walkway

38. Scylla. In the first year (continued) 15. much of vessel still very bare (grazed); By the end of and after one year (50-55 weeks): 16. but, algae have returned; 17. common starfish declining and green sea urchins possibly less abundant.

39. 19 March 2005 The bow: still very grazed

40. By the end of one year, we had: 1. recorded (through the year and from various sources) a total of 53 species on or in Scylla (excluding surrounding seabed species); 2. been able to track sequence of species colonisation (and loss) through the year; 3. had a few surprises (unexpected settlements).

41. In the second year (2005): losses and gains 1. Grazing much less (sea urchins decline dramatically, starfish less abundant). 2. Some significant new species settle. 3. Plumose anemones become visually dominant in many areas. 4. In the reduced grazing regime, tubeworms, barnacles and foliose algae thrive.

42. Urchin midden 15 July 2005

43. Algae have colonised the foredeck – but a small variety of filamentous species 7 September 2005

44. Jewel anemones 7 September 2005

45. Jewel anemones 20 August 2006

46. Dead mens fingers 15 July 2005

47. 20 August 2006 Leathery sea squirts – present from about October 2004, common by 2006

48. During the winter 2005-6 and into 2006, visually dominant species expand and the reef communities begin to stabilize. 1. Plumose anemones are abundant in some areas 2. Dead mans fingers are common and grow to full size 3. Leathery sea squirts begin to be conspicuous But still room for more – especially inside

49. Plumose anemones on prop shaft 28 January 2006

50. Still plenty of room inside 28 January 2006

51. Ross, Pentapora fascialis 25 March 2006

52. Omalosecosa ramulosa: a branching sea mat (bryozoan) 20 August 2006

53. Sea beard, Nemertesia antennina, first seen winter 05/06 30 August 2006

54. Dead mens fingers now common and nearly full grown (and more have settled) 18 August 2006

55. Top of the reef colonised by expected variety of seaweeds including kelp 18 August 2006

56. Foredeck colonised by expected variety of foliose seaweeds 20 August 2006

57. Lots more fish by end of summer 2006 – scad off the bow 20 August 2006

58. The urchins are back! (but not so many) – and a 2006 settlement of dead mens fingers 20 August 2006

59. The scallops are back! (but not so many) 20 August 2006

60. Records of dahlia anemones confirmed (Image: Sally Sharrock) 28 August 2006

61. Sagartia elegans rosea 7 October 2006

62. Many parts of the outside of the reefs are solid with colonisation and a wide variety of species 18 August 2006

63. Some parts of the reefs might even qualify as pretty 18 August 2006

64. But, colonisation of the anti-fouling-painted areas restricted to patches where paint has flaked (under the stern) 18 August 2006

65. By end of August 2006 (from our Wanted list of spring 2005 & before Scylla week): White sea fingers Red sea fingers Ross Edible sea urchin Pink sea fan Devonshire cup corals First seen June 2005 First seen Sept 2005 First seen March 2006 Still looking 126 species recorded from Scylla from observations and photographs Still looking

66. Sampling the little beasties (worms, crustaceans etc.) 30 August 2006 and during the subsequent Scylla Week

67. About 84 additional species identified by Unicomarine from samples taken in Scylla Week, bringing the total number of species identified on Scylla to about 220

68. By the end of 2006, most of the species that were to be visually dominant on the reef had settled. But those species had to expand in abundance and grow in size before Scylla would qualify as hosting a mature steel wreck community. And some expected species were still unaccounted for.

69. 27 April 2007 Red sea fingers were first seen in April 2007

70. 17 August 2007 Orange pumice bryozoan, Cellepora pumicosa were first observed in late summer 2006 and, unexpectedly, became extremely abundant in the next year.

71. 15 June 2007 By summer 2007, established species characteristic of wrecks were growing towards full size: dead mans fingers, ross and orange pumice bryozoans were abundant

72. 19 September 2008 Sea urchins, Echinus esculentus were not reported from the reef until 30 September 2007

73. 10 December 2008 Seafans, Eunicella verrucosa, settled in about July 2007 – and some grew rapidly

74. 19 September 2008 Feather stars, Antedon bifida only became abundant in 2008

75. There are significant seasonal changes on Scylla – winter scene with few algae on shallow decks 10 December 2008

76. Two of the conspicuous characterising animals, species of oaten pipe hydroids, are devastated by sea slugs in summer and die back in late-winter.

77. 26 February 2009 Spring growth beginning – sea beech Delesseria sanguinea

78. 26 February 2009 Topknot braving the anti-fouling paint under the stern

79. By end of March 2009 (from our Wanted list of spring 2005 & after Scylla week): Dead mans fingers Red sea fingers Ross Edible sea urchin Pink sea fan Devonshire cup corals First seen June 2005 First seen Sept 2005 First seen March 2006 First seen Sept 2007 First seen August 2007 258 species recorded from Scylla from observations, photographs and samples First seen April 2007

80. Some species are expected to increase in abundance over the next few years: Fish, especially wrasse Edible sea urchins Devonshire cup corals

81. We are still waiting to see some species that occur commonly on steel wrecks in south Devon and Cornwall: Lobster Cotton spinner Yellow boring sponge (massive form) Sandaled anemone Actinothoë sphyrodeta

82. Scylla now hosts (March 2009, five years after placement) a mature steel wreck wildlife community

83. Report any unusual or interesting marine life (supported by images where possible): Get this presentation: www.marlin.ac.uk/learningzone/scylla MarLIN 24 hr reporting hotline: 01752 255026 E-mail images to: marlin@mba.ac.uk Join-up: www.mcsuk.org; www.seasearch.org.uk