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Host specificity, spatial niche diversity and adaptations of coral-associated gobies in the northern Red Sea. J. Herler, M. Dirnwöber, L. Schiemer, S. Niedermueller. Introduction M&MResults & Discussion. Overview Short introduction to coral-associated gobies - PowerPoint PPT Presentation
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J. Herler, M. Dirnwöber, L. Schiemer, S. Niedermueller
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
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
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
„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
Gobiodon Bryaninops
Eviota
Paragobiodon
DiversityIndo-Pacific: 160 – 200 species Red Sea: ~ 30 species reported
Pleurosicya Trimma
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
1 cm
Priolepis
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
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
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
Molecular tree: 12S, 16S, cyt bConsensus of NJ, MP, ML, BI
(NJ)
PproBnatByonPmicBridEgutEpraEseeEzebTaviTmenEdisPsemGsp2GcitGretGrivGsp1GhisGsp3Pech
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
MorphometricTree
coral rock
live coral
Bray Curtis – similarity
0
10
20
30
40
50
60
70
80
90
juvenile
adult
Gobiodon histrio N = 358
0
50
100
150
200
250 Gobiodon reticulatus N = 330
0
10
20
30
40
50
60 Gobiodon rivulatus N = 327light form
0
10
20
30
40
50
60 Gobiodon rivulatus N = 104dark form
0
10
20
30
40
50
60
70
80 Gobiodon species 1 N = 336
0
10
20
30
40
50
60 Gobiodon species 2 N = 69
0
5
10
15
20
25
30
35
40
45
50 Gobiodon species 3 N = 102
0
10
20
30
40
50
60
70
80
90
juvenile
adult
Gobiodon histrio N = 358
0
50
100
150
200
250 Gobiodon reticulatus N = 330
0
10
20
30
40
50
60 Gobiodon rivulatus N = 327light form
0
10
20
30
40
50
60 Gobiodon rivulatus N = 104dark form
0
10
20
30
40
50
60
70
80 Gobiodon species 1 N = 336
0
10
20
30
40
50
60 Gobiodon species 2 N = 69
0
5
10
15
20
25
30
35
40
45
50 Gobiodon species 3 N = 102
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
Microhabitatgeneralists
Zonespecialist
Microhabitatspecialists
-0.08
-0.06
-0.04
-0.02
0.00
0.02
0.04
-0.06 -0.04 -0.02 0.00 0.02 0.04 0.06
PC 2
PC 1
cit his ret rivsp1 sp2 sp3
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
Geometric morphometrics
RW 1
RW 2
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
Regressions of RW1 (GM) against body size, depth and width
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
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.
0
1
2
3
4
5
6
7
0 10 20 30 40
0
1
2
3
4
5
6
7
0 10 20 30 400
1
2
3
4
5
6
7
0 10 20 30 40
0
1
2
3
4
5
6
7
0 10 20 30 40
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
inte
rbra
nch
spa
ce (
mm
)m
ax.
he
ad w
idth
(m
m)
coral colony size (mm)
fish body length (mm)
Threshold Threshold
Acropora digitifera Acropora acuminata
Gobiodon histrio Gobiodon rivulatus
R2 = 0.90p < 0.001
R2 = 0.92p < 0.001
2
3
4
5
6
10 15 20 25 30 35 40
R2 = 0.90p < 0.001
R2 = 0.92p < 0.001
2
3
4
5
6
10 15 20 25 30 35 40
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
Aquarium experiments: swimming performance
15% size diff.
G. histrio G. rivulatus
coralinter-branchspacerange
fish size (mm SL)
min
ima
l int
erb
ran
ch d
ista
nce
pas
sed
(m
m)
Introduction M&M Results & Discussion
Herler et al., ICRS 2008: Coral gobies
Different species of Acropora host corals show different susceptibility to stressPMI = 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%
PMI:
Herler et al., ICRS 2008: Coral gobies
P-10.374
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
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
