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Revealing the reef: marine life settling on ex-HMS

Scylla Keith Hiscock

Last updated: 9th March 2009

Including information from the Settling on Scylla project

Get this presentation: www.marlin.ac.uk/learningzone/scylla

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.)

19 November 2003. Devonport

Inspection of existing fouling

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

27 March 2004

www.national-aquarium.co.uk

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

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.)

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.

Other UK artificial reefs: local wrecks

Persier

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.);

Poor cod

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

9 June 2004

Brown filamentous algae

25 June 2004

Spiny starfish, Marthasterias glacialis

30 July 2004

Keeled tube worms, Pomatoceros triqueter, saddle oysters, Heteranomia squamula etc.

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, many ‘decorata’ 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;

30 July 2004

Queen scallops settle

18 February 2005

Queen scallop, Aequipecten opercularis inside the vessel

30 July 2004

Decorata anemone, Sagartia troglodytes decorata

9 June 2004

Tubularia hydroid

9 June 2004

Encrusting sea mat, ?Electra pilosa

30 July 2004

Solitary sea squirts, Ciona intestinalis

30 July 2004

Brown alga, Cutleria multifida

30 July 2004

Filamentous red algae

30 July 2004

Facelina bostoniensis and eggs

30 July 2004

25 September 2004

By end of the summer: dense colonisation – but the urchins and starfish have settled

10 November 2004

Mussels, Mytilus edulis Image: Sally Sharrock

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;

18 February 2005

Green sea urchin Psammechinus miliaris

18 February 2005

Common starfish, Asterias rubens

18 February 2005

Cleaned by urchins & starfish

18 February 2005

Plumose anemone, Metridium senile

18 February 2005

Calcareous sponges, Leucosolenia botryoides & Sycon ciliatum

18 February 2005

Colonisation on below-waterline black paint. Effective antifouling paint

30 January 2005

Corkwing wrasse on the starboard walkway

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.

19 March 2005

The bow: still very grazed

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).

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.

Urchin midden

15 July 2005

Algae have colonised the foredeck – but a small variety of filamentous species

7 September 2005

Jewel anemones

7 September 2005

Jewel anemones

20 August 2006

Dead mens fingers

15 July 200515 July 2005

20 August 2006

Leathery sea squirts – present from about October 2004, common by 2006

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 man’s fingers are common and grow to full size

3. Leathery sea squirts begin to be conspicuous

But still room for more – especially inside

Plumose anemones on prop shaft

28 January 2006

Still plenty of room inside

28 January 2006

Ross, Pentapora fascialis

25 March 2006

Omalosecosa ramulosa: a branching sea mat (bryozoan)

20 August 2006

Sea beard, Nemertesia antennina, first seen winter 05/06

30 August 2006

Dead mens fingers now common and nearly full grown (and more have settled)

18 August 2006

Top of the reef colonised by ‘expected’ variety of seaweeds including kelp

18 August 2006

Foredeck colonised by ‘expected’ variety of foliose seaweeds

20 August 2006

Lots more fish by end of summer 2006 – scad off the bow

20 August 2006

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

20 August 2006

The scallops are back! (but not so many)

20 August 2006

Records of dahlia anemones confirmed (Image: Sally Sharrock)

28 August 2006

Sagartia elegans rosea

7 October 2006

Many parts of the outside of the reefs are ‘solid’ with colonisation and a wide variety of species

18 August 2006

Some parts of the reefs might even qualify as “pretty”

18 August 2006

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

18 August 2006

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 First seen June 2005June 2005

First seen First seen Sept 2005Sept 2005

First seen First seen March 2006March 2006 Still lookingStill looking Still lookingStill looking

126 species recorded from Scylla from observations and photographs

Still lookingStill looking

Sampling the little beasties (worms, crustaceans etc.)

30 August 2006 and during the subsequent Scylla Week

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

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.

27 April 200727 April 2007

Red sea fingers were first seen in April 2007Red sea fingers were first seen in April 2007

17 August 200717 August 2007

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

15 June 200715 June 2007

By summer 2007, established species characteristic of wrecks were growing By summer 2007, established species characteristic of wrecks were growing towards full size: dead man’s fingers, ross and orange pumice bryozoans were towards full size: dead man’s fingers, ross and orange pumice bryozoans were abundantabundant

19 September 200819 September 2008

Sea urchins, Sea urchins, Echinus esculentusEchinus esculentus were not reported from the reef until 30 were not reported from the reef until 30 September 2007September 2007

10 December 200810 December 2008

Seafans, Seafans, Eunicella verrucosaEunicella verrucosa, settled in about July 2007 – and some grew rapidly, settled in about July 2007 – and some grew rapidly

19 September 200819 September 2008

Feather stars, Feather stars, Antedon bifidaAntedon bifida only became abundant in 2008 only became abundant in 2008

There are significant seasonal changes on Scylla – winter scene with few algae on There are significant seasonal changes on Scylla – winter scene with few algae on shallow decksshallow decks

10 December 200810 December 2008

10 December 200810 December 2008

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

26 February 200926 February 2009

Spring growth beginning – sea beech Spring growth beginning – sea beech Delesseria sanguineaDelesseria sanguinea

26 February 200926 February 2009

Topknot ‘braving’ the anti-fouling paint under the sternTopknot ‘braving’ the anti-fouling paint under the stern

By end of March 2009 (from our ‘Wanted’ list of spring 2005 & after ‘Scylla week’):

Dead man’s fingers Red sea fingers

Ross Edible sea urchin Pink sea fan

Devonshire cup corals

First seen First seen June 2005June 2005

First seen First seen Sept 2005Sept 2005

First seen First seen March 2006March 2006

First seen First seen Sept 2007Sept 2007

First seen First seen August 2007August 2007

258 species recorded from Scylla from observations, photographs and samples

First seen First seen April 2007April 2007

Some species are expected to increase in abundance over the next few years:

Fish, especially wrasse

Edible sea urchins

Devonshire cup corals

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

Scylla now hosts (March 2009, five years after placement) Scylla now hosts (March 2009, five years after placement)

a mature steel wreck wildlife communitya mature steel wreck wildlife community

Report any unusual or interesting marine Report any unusual or interesting marine life (supported by images where possible):life (supported by images where possible):

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