Anomastraea irregularis, a Vulnerable coral of the rocky interdal zone of Watamu Marine Naonal Park, Kenya

Cassie Raker, Benjamin Cowburn, Victoria Sindorf, Peter Musembi, Benjamin Vanbaelenberghe, and Robert D. Sluka A Rocha Kenya, Marine Conservaon and Research Programme, Watamu, Kenya [email protected]

INTRODUCTION The scleracnian coral Anomastrea irregularis is a rare coral usually found in rock pools or at the base of fringing reefs. It is classified as vulnerable on the IUCN Red List of Threatened , and is a target conservaon species of the EDGE (Evoluonarily Disnct and Globally Endangered) Programme. A. irregularis generally forms small massive colonies that are brown in color. The corallites form an irregular honeycomb paern. Previously there have been no published studies focusing solely on A. irregularis, and lile is known about its ecological significance. A. irregularis is relavely common in the Watamu Naonal Marine Park (WNMP) on the coast of Kenya. The WNMP was established in 1968 and covers around ten square kilometers of marine habitat, including lagoonal reefs and rock pools. The park is completely closed to fishing and other extracve acvies. However, there has been significant impact of tourism on the most heavily visited site and our observaons suggest that many tourists also visit rockpools to view marine life. This study provides the first observaons on the density and distribuon of Anomastrea irregularis in East Africa and aempts to determine ecological factors influencing this distribuon.

Turtle Bay: sheltered

Plot 34: sheltered

Garoda: exposed

Map of WNMP: major study sites marked in red Clockwise from upper le – study site located at Turtle Bay; a typical rockpool containing A. irregularis as well as various RESULTS other life; Pavona frondifera and Acropora bruggemanni, other coral species commonly observed in WMNP rockpools. • 131 total colonies: 20 at Garoda (exposed); 36 at Plot 34 (sheltered); 75 at Turtle Bay 70 A 120 B (sheltered) 60 • Most corals located on seaward facing wall of 100 rockpools 50 • No significant relaonship between the height 80 40 of the colony from the boom of the pool and Sand/Rub 60 Coral the size of the colony Colony Height 30 Dead Sg Pool Depth Percent cover • Exposed colonies were outliers with Seagrass significantly deeper, smaller pools with more 40 Algae Colony height/pool depth (cm) 20 colonies per pool. 20 • Colonies at the two sheltered sites were most 10 frequently found singly. • Exposed pools were frequently dominated by 0 0 Turtle Bay Plot 34 Garoda Total P34 TB Gar Total sand/rubble and algae, while sheltered sites Site Site showed a much higher seagrass presence A. Average A. irregularis height above the boom of the pool compared with B. Average percent cover of five major benthic categories compared over all • A. irregularis does not seem posively or average pool depth (cm) sites negavely affected by the presence of other coral species. CONCLUSIONS • Coral species observed in rockpools: • Anomastrea irregularis generally form small, seaward facing colonies in producve pools near the seaward edge of rockpool • Anomastrea irregularis areas • Pseudosiderastrea tayami • Exposed and sheltered sites seem to show significantly different ecological trends • Hydnophora microconos •More informaon is needed on A. irregularis populaon dynamics and reproducve strategies • Favia speciosa •Rockpools in this naonal park not acvely protected through the current management plan. Understanding the importance • Pavona frondifera of this habitat to local biodiversity will lead to beer future protecon. • fascicularis • Acropora bruggemanni • Porites spp. ACKNOWLEDGEMENTS We would like to thank the Kenya Wildlife Service for their support in conducng this research. We would also like to thank Udit Chohan, • Psammacora sp. Hannah Hereward, and Dorothea Kohlmeier for their assistance with data collecon. And a huge thank you to the enre A Rocha Kenya team • Platygyra sp. for their constant encouragement and support.