Supporting information
Temporal Dynamics of Top Predators Interactions in the Barents Sea
Joël M. Durant, Mette Skern-Mauritzen, Yuri V. Krasnov, Natalia G. Nikolaeva, Ulf Lindstrøm,
Andrey Dolgov
Table S1. Diet of the different predators.
Black-legged
kittiwake
Rissa tridactyla
Common
guillemot
Minke whale
Northeast
Arctic cod
Uria aalge
Gadus morhua
Years
1982-1999
1984-1999
Balaenoptera
acutorostrata
1992-2004
n
18
16
13
26
Latitude
Longitude
Niche breadth D
(range)
68°78
37°33
1.09 ± 0.28(SD)
(0.45 – 1.65)
68°78
37°33
0.79 ± 0.31(SD)
(0.39 – 1.42)
69°83-80°28
6°54-38°65
1.25 ± 0.21(SD)
(0.66 – 1.49)
Barents Sea
Prey species
Herring
Capelin
Cod
Haddock
Sandeel
Salmon
Bullhead
Butterfish
Blenny
Herring
Capelin
Cod
Sandeel
Redfish
Wolfish
Blenny
Herring
Capelin
Cod
Haddock
Saithe
Sandeel
Mackerel
Krill
Unidentified
codfish
Other fish
Herring
Capelin
Cod
Haddock
Blue whiting
Polar cod
Redfish
Long rough dab
Greenland halibut
Bottom fish
1984-2009
1.51 ± 0.21(SD)
(1.00 – 1.81)
Krill
Other fish
Amphipods
Crustaceans
Shrimp
Offal
Other
D is the Shannon-Wiener niche breadth index calculated as follows:
D = - Σ Pi*ln(Pi)
where pi is the proportion of the species considered feeding on prey species/group i.
1
Table S2. Prey species and categories used for the calculation of the Schoeners’ index.
Category
Capelin
Herring
Cod
Haddock
Other gadoids
Saithe
Polar cod
Sandeel
Redfish
Flatfish
Krill
Amphipods
Crustaceans
Other fishes
Offal
Other
species
Mallotus villosus
Clupea harengus
Gadus morhua
Melanogrammus aeglefinus
e.g., Blue whiting (Micromesistius poutassou) or unidentified gadoids
Pollachius virens
Boreogadus saida
Ammodytidae
Sebastes sp.
e.g., long rough dab (Hippoglossoides platessoides), Greenland halibut
(Reinhardtius hippoglossoides) etc
Euphausiids
Hyperiids
e.g., shrimp Pandalus borealis
every fish not in the above categories
fish rest
stomach content of cod: mush
To calculate the diet overlap between species we needed the same number of categories for each
predator diet. We have put in the same categories some prey such as halibut and plaice in the
flatfish category... Intraspecific diet overlap analysis was conducted on unmodified data as
extract from our sources (see Table S1).
2
3
100
80
60
0
20
40
Common guillemot diet
80
60
40
20
0
1985
1990
1995
2000
1985
1990
2000
Sandeel
Amphipods
Other
60
Cod
Polar.cod
Krill
Offal
Herring
Saithe
Flatfish
Other Fish
Redfish
Crustaceans
80
Haddock
40
100
Legends
20
Minke whale diet, 70-74°N and 20-40°E
80
60
40
0
Capelin Other gadoids
1998
2000
2002
2004
1992
1994
1996
1998
2000
2002
2004
100
NEA cod diet, 70-80°N and 5-40°E
80
60
40
1985
1990
1995
Years
2000
2005
2010
0
20
0
0
20
40
60
80
NEA cod diet, 68-72°N and 20-40°E
100
Years
100
Years
80
1996
60
1994
40
Minke whale diet
20
0
1992
NEA cod diet ICES
1995
Years
100
Years
20
Black-legged kittiwake diet
100
Figure S1. Diet of the main predator species in the Barents Sea over time.
1985
1990
1995
Years
2000
1992
1994
1996
1998
2000
2002
2004
Years
Note that for the black-legged kittiwakes and common guillemots the amphipods and krill prey species where not dissociated and are
assembled in one category “krill”. There are two minke whale diet plots: for the whole Barents Sea (left) and restricted to the Southern
Barents Sea part (70-74°N and 20-40°E). The first data are used to analyse the change in the minke whale diet over time and to
compare with the diet of the NEA cod. The second data are used to compare with the diet of the seabirds that are central place foragers
and limited to the Southern Barents Sea during reproduction (period when the seabird diet data were collected). There are three NEA
cod plots: for the ICES data (1984-2009) used for the intraspecific analysis and for restricted area of the Barents Sea to compare with
the seabirds’ diet (March to July, 68-72°N and 20-40°E ) and with the minke whale’s diet (July to September, 70-80°N and 5-40°E).
4
5.0
4.5
4.0
3.5
Sea temperature, °C
Figure S2. Time series used as explanatory variables in the study.
1985
1990
1995
2000
2005
2010
2000
2005
2010
2000
2005
2010
2000
2005
2010
4
2
0
-2
-4
winter NAO index
Years
1985
1990
1995
0
2
4
6
6
Capelin biomass, 10 t
Years
1985
1990
1995
0.0
1.0
2.0
6
Young hering biomass, 10 t
Years
1985
1990
1995
6
5
2
3 4
Total abundance
Northw estern Barents Sea
1
Krill indice, individuals m
3
Years
1985
1990
1995
2000
2005
2010
Years
5
Data for the winder NAO come from
https://climatedataguide.ucar.edu/sites/default/files/climate_index_files/nao_station_djfm.txt.
Data for the sea temperature come from PINRO. They are yearly average sea temperature
measured monthly at 0-200 m depth on the Russian Kola meridian transect (33° 30’ E, 70° 30’ N
to 72° 30’ N).
Data for capelin and herring biomass come from ICES report (Table 9.5 p 498 in ICES 2012).
6
1990
1995
0.4
0.6
0.8
1.0
1985
0.0
a. Minke w hale vs Cod
0.2
Schoeners' diet overlap
0.8
0.6
0.4
0.2
0.0
Schoeners' diet overlap
1.0
Figure S3. Interspecific diet overlap for the main predator species in the Barents Sea.
2000
2005
b. Kittiw ake vs Minke w hale
1985
1990
2000
2005
2000
2005
2000
2005
1.0
Years
1.0
Years
1995
0.8
0.6
0.4
0.0
0.2
Schoeners' diet overlap
0.8
0.6
0.4
0.2
0.0
Schoeners' diet overlap
c. Kittiw ake vs Cod
1985
1990
1995
2000
2005
d. Kittiw ake vs Guillemot
1985
1990
1.0
Years
1.0
Years
0.6
0.4
0.0
0.2
Schoeners' diet overlap
0.6
0.4
0.2
0.0
0.8
f. Minke w hale vs Guillemot
0.8
e. Guillemot vs Cod
Schoeners' diet overlap
1995
1985
1990
1995
Years
2000
2005
1985
1990
1995
Years
Change of diet from one year to another is presented by a Schoeners’ diet overlap index (grey
filled dots). Higher is the index higher is the overlap.
7