Trophic Signatures of Marine Organisms
in the Mediterranean as Compared with
Other Ecosystems
Rainer Froese1, Stefan Garthe2,
Daniel Pauly3, Uwe Piatkowski1
1) Institute of Marine Research, Düsternbrooker Weg 20, 24105
Kiel, Germany, rfroese@ifm.uni-kiel.de
2) Research and Technology Centre (FTZ), University of Kiel,
Hafentörn, 25761 Büsum, Germany
3) Fisheries Centre, 2204 Main Mall, University of British Columbia,
Vancouver, B.C., Canada V6T 1Z4
Content of Presentation
•
•
•
•
Large Marine Ecosystems
Material and Methods
Comparing the Mediterranean
Scale-free Networks
Large Marine Ecosystems
• An Introduction to LMEs >>
• What are the LMEs >>
Material & Methods
•
•
•
•
•
•
What are Trophic Levels? >> >>
How to Estimate Trophic Levels >> >>
Marine Mammals Data (Daniel Pauly)
Marine Birds Data (Stephan Garthe)
Cephalopod Data (Uwe Piatkowski)
Fish Data (www.fishbase.org)
>>
How to Estimate Trophic Levelss
Troph = mean troph of food items + 1
where the mean is weighted by the contribution of the different food items
TL = (50% * TL1 + 50% * TL 2 ) / 100% + 1 = 2.5
<<
Global Marine Fish Species by Trophic Level
5
4.5
Trophic Level
4
3.5
Troph = 3.2
3
2.5
2
1
10
100
Num ber of Fish Species
1000
10000
Fish in the Mediterranean
5
Trophic Level
4.5
4
3.5
trophic level
3.2
3
2.5
2
1
10
100
Num ber of Fish Species
1000
10000
Mediterranean vs Tropical
5
South China Sea
4.5
Caribbean
Mediterranean
Trophic Level
4
3.5
3
2.5
2
1
10
100
Num ber of Fish Species
1000
10000
Mediterranean vs Temperate
5
Baltic
4.5
Black Sea
North Sea
Mediterranean
Trophic Level
4
3.5
3
2.5
2
1
10
100
Num ber of Fish Species
1000
10000
Comparison of Six LMEs
5
Baltic
Black Sea
4.5
South China Sea
Caribbean
North Sea
Trophic Level
4
Mediterranean
3.5
trophic level
3.2
3
2.5
2
1
10
100
Num ber of Fish Species
1000
10000
Size of Mediterranean Fishes
5.0
4.5
Trophic level
4.0
3.5
3.0
2.5
2.0
0
50
100
150
Mean max. length (cm TL)
200
Size in other LMEs
5
4.5
Trophic Level
4
3.5
Baltic
3
Black Sea
South China Sea
Caribbean
2.5
North Sea
2
0
50
100
Mean m ax. Length (cm TL)
150
200
Mediterranean Size vs Other LMEs
5
4.5
Trophic Level
4
3.5
Baltic
Black Sea
3
South China Sea
Caribbean
2.5
North Sea
Mediterranean
2
0
50
100
Mean m ax. Length (cm TL)
150
200
Distribution vs Length
Distribution as function of body size in marine
fishes (Number of Countries vs Length)
200
Number of Countries
180
160
140
120
100
80
60
40
20
0
0.1
1
10
100
Length (cm)
1000
10000
Distribution vs Length:
Mediterranean
Mediterranean
200
Number of Countries
180
160
140
120
100
80
60
40
20
0
0.1
1
10
100
Length (cm)
1000
10000
Mammals, Birds and Cephalopods
in the Mediterranean
5.0
4.5
Trophic Level
Birds (48)
4.0
Mammals (17)
3.5
Cephalopods (59)
Fish (567)
3.0
2.5
2.0
1
10
100
Number of Species
1000
Mammals, Birds, and Cephalopods
in the North Sea
5
Marine
Mammals (22)
Trophic Level
4.5
4
Cephalopods (20)
Birds (69)
3.5
Fish (186)
3
2.5
2
1
10
100
Number of Species
1000
Trophic Pyramid Mediterranean
Birds
4.5-5
Mammals
4-4.5
Fish
Cephalopods
3.5-4
Benthic invertebrates
3-3.5
Planktonic
invertebrates
2.5-3
2-2.5
0
1000
2000
3000
4000
5000
Trophic Pyramid North Sea
Fish
4.5-5
Birds
Mammals
Trophic Levels
4-4.5
Cephs
Benthic invertebrates
3.5-4
Planktonic invertebrates
3-3.5
2.5-3
2-2.5
0
500
1000
Number of Species
1500
Summary on Trophic Signatures
• Trophic signatures represent long-term
characteristics of ecosystems
• They are useful to compare and classify
ecosystems
• Trophic species pyramids also appear to
be promising decriptors
• Taxonomy and trophic relationships of
invertebrates need more attention
Distributions I
• Many biological parameters have a normal
or log-normal distribution:
– size at age
– offspring per female
– oxygen consumption per body mass
– distance between worm holes
– species counts per area in a given habitat
Distributions II
• Many other biological parameters follow a
(negative) power function:
– number of sexual partners
– number of habitats
– number of food items
• Such distributions are scale-free networks
Scale-free Network Mediterranean
Scale-free Fish Foodweb Mediterranean
Species with k Food Categories
120
100
80
60
40
20
0
0
5
10
15
Number (k) of Food Categories
20
25
Thank You