Coral-Associated Gobies in the Red Sea: Host Specificity, Niche Diversity, and Adaptations

1. Host specificity, spatial niche diversity and adaptations of coral-associated gobies in the northern Red Sea J. Herler, M. Dirnwöber, L. Schiemer, S. Niedermueller

2. Introduction M&M Results & Discussion • Overview • Short introduction to coral-associated gobies • Brief overview about methods (DNA, habitats, shape) • Results and discussion of molecular, ecological and morphological analyses • Research perspectives Herler et al., ICRS 2008: Coral gobies

3. Introduction M&M Results & Discussion „Thumbnail gobies“: size range: 9 – 50 mm SL • Bi-directional sex changers • Hypoxia tolerance (Gobiodon) • Toxic skin (Gobiodon) • Specific habitat choice • Competitive hierarchy (Gobiodon) Munday, Nilsson, Schubert and others Herler et al., ICRS 2008: Coral gobies

4. Introduction M&M Results & Discussion 1 cm Bryaninops Paragobiodon Gobiodon Trimma Eviota Pleurosicya Diversity Indo-Pacific: 160 – 200 species Red Sea: ~ 30 species reported Priolepis Herler et al., ICRS 2008: Coral gobies

5. IntroductionM&MResults & Discussion • Ecological data: • 5-10 x 1m belt transects • Random swims, random plots • Aquarium experiments • Morphological data: • Traditional morphometrics (cluster, size constraints) • Geometric morphometrics (shape variation within Gobiodon) • Molecular data: • Partial sequences of mitochondrial genes: 12S rRNA, • 16S rRNA and cyt b Herler et al., ICRS 2008: Coral gobies

6. Introduction M&MResults & Discussion Molecular tree: 12S, 16S, cyt b Consensus of NJ, MP, ML, BI (NJ) Herler et al., ICRS 2008: Coral gobies

7. coral rock live coral Introduction M&MResults & Discussion Ppro Bnat Byon Pmic Brid Egut Epra Esee Ezeb Tavi Tmen Edis Psem Gsp2 Gcit Gret Griv Gsp1 Ghis Gsp3 Pech Morphometric Tree Bray Curtis – similarity Herler et al., ICRS 2008: Coral gobies

8. Introduction M&MResults & Discussion Zone specialist Microhabitat generalists Microhabitat specialists Herler et al., ICRS 2008: Coral gobies

9. Introduction M&MResults & Discussion Geometric morphometrics RW 1 RW 2 Herler et al., ICRS 2008: Coral gobies

10. Introduction M&MResults & Discussion Regressions of RW1 (GM) against body size, depth and width Herler et al., ICRS 2008: Coral gobies

11. Introduction M&MResults & Discussion G. histrio shows a split in the increase and lower variation in body depth with growth than G. rivulatus. Both species show a reduction of their head width during growth but this is stronger in G. histrio. Herler et al., ICRS 2008: Coral gobies

12. Threshold Threshold Introduction M&MResults& Discussion Acropora acuminata Acropora digitifera interbranch space (mm) coral colony size (mm) Gobiodon rivulatus Gobiodon histrio max. head width (mm) fish body length (mm) Herler et al., ICRS 2008: Coral gobies

13. coral inter- branch space range 15% size diff. Introduction M&MResults & Discussion Aquarium experiments: swimming performance G. histrio G. rivulatus minimal interbranch distance passed (mm) fish size (mm SL) Herler et al., ICRS 2008: Coral gobies

14. Introduction M&MResults& Discussion PMI: Different species of Acropora host corals show different susceptibility to stress PMI = partial mortality index Breeding pairs of gobies prefer corals with little or no damage: Occupation of undamaged colonies = 5 x occupation of corals with PM > 70% Herler et al., ICRS 2008: Coral gobies

15. P-10.374 Herler et al., ICRS 2008: Coral gobies

16. Perspectives Adaptations to microhabitats: Important traits for ecological performance? Fitness consequences of the use of alternative habitats after habitat loss? Goby-coral associations: What kind of relationship is it: mutualism, commensalism? Parallel evolution between coral and fish? Diversification: Is there additional ecological/morphological diversification other than spatial niche diversification, for example trophic niche differentiation? Herler et al., ICRS 2008: Coral gobies

17. Many thanks to ... • Austrian Academy of Sciences • Moustafa Fouda (EEAA, Egypt) • Ayman Mabrouk (Nabq MPRA, Egypt) • Helge Hilgers (University of Vienna, Austria) • Phil Munday (JCU, Australia) • Carden Wallace (MTQ, Australia) • Rick Winterbottom (ROM, Canada) • my students: Markus, Mona, Lucie, Marlene, Eva • Dahab Association for Environmental Development • ICRS – committee • millions of gobies that (still) exist • you, for your attention