Climate, oceanographic conditions and
trophic interactions in a marine system:
seabird-fish
CEES
Joë
Joël M. Durant1,*, Tycho AnkerAnker-Nilssen2, Dag Ø. Hjermann1 & Nils Chr. Stenseth1,3
1Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, PO Box 1050 Blindern, NO-0316 Oslo, Norway.
2 Norwegian Institute for Nature Research (NINA), Tungasletta 2, NO-7485 Trondheim, Norway.
3 Flødevigen Marine Research Station, Institute of Marine Research, NO-4817 His, Norway.
INTRODUCTION
In seasonal environments, one of the main challenges for breeding individuals is to match food
supply to breeding and offspring requirements. However, prey availability depends on a variety of
physical factors and food-chain interactions that are affected by climate variation. Moreover prey
availability and predator breeding decision may not depend on the same environmental conditions
leading to a mismatch between requirement and availability. Studying top predator response to
environment changes gives insight on the whole trophic chain. E.g., in long-lived birds with singleegg clutches, the adequate timing of reproduction in regard to food availability is then essential for
the reproductive output.
70°
Lofoten
cu
rr e
nt
▶
68°
No
rw
eg
ia
n
Røst
Figure 1: Geographical position of Røst archipelago in northern Norway. The blue dotted line represents the limit of the
Norwegian shelf and of the influence of the northward Norwegian coastal current. The circle is the maximum extension of
foraging (150 km) for Atlantic puffins (Fratercula arctica) breeding at Røst1. Note that the whole extent of the continental shelf
is explored by foraging Atlantic puffins during breeding. The inside map represents the northward drift of the main prey of the
Atlantic puffin during reproduction, the first-year herring (Clupea harengus), from their birth area in southern Norway following
the Norwegian coastal current
Herring
spawning
66°
NORWAY
500 m
5°
10°
15°
20°
METHODS
Herring: As estimate of the quantity and quality
of herring we used the length of the herring
found in food loads intended for puffin chicks.
This measure was found to be highly correlated
to the estimated herring year class strength by
Virtual Population Analysis2
Puffin: We used the annual fledging success
estimated as the proportion of eggs hatched
producing a fledgling, and the mean duration of
the nestling period (annual average 64 study
nests).
Climate: Sea temperature ST and salinity Sal
were measured at two locations north-east of
Røst archipelago3. From these data we
calculated an average Sal and ST for the water
column explored by the Atlantic puffin when
foraging (0-75 m) off Røst during the breeding
period1.
North Atlantic Oscillation4,5 NAO is an
integrated measure linked to many climatic
variables such as precipitation, wind speed and
temperature over a large part of the Northern
Hemisphere5.
Statistics: modellisation and model selection
(green lines in fig 2-4) by AIC was conducted
using S-plus6.
Fledging success (0 to 1)
1
0.8
0.6
0.4
0.2
0
RESULTS
1975
1980
1985
1990
1995
2000
Year
Hatching date (June-July), days
Figure 3. Puffin fledging success can be explained by
STt, and Herring lengtht F2,18=46.57, p<0.0001, r2 =
0.84b
CLIMATE
30
Nestling period, days
20
60
10
50
30
40
20
Fledging success
Good
Poor
Failed
30
Copepods
10
1980
1985
1990
1995
2000
Herring
Puffins
0
Year
Figure 2. Puffin hatching date can be explained by
NAOt, Herring lengtht-1 and Hatching datet-1.
F3,7=13.93, p=0.003, r2 = 0.86a.
20
10
The studied system
1980
Correlations
NAO vs. ST
NAO vs. Hatch date
VPA vs. Herring length
1984
1988
1992
1996
2000
Year
p < 0.01
p = 0.015
p < 0.05
r24 = 0.541
Figure 4. Puffin nestling period can be explained by ST ,
r21 = 0.501 and Sal F =29.57, p<0.0001, r2 = 0.75c. The fledging t
t 2,20
r17 = 0.636 success is indicated by different colors.
DISCUSSION
Climate was shown to affect the breeding of the Atlantic puffin. ST and Sal (Fig. 3-4), two variables
known to affect fish development, as well as NAO (Fig. 2), known to affect abundance of marine
fishes and zooplankton5, were shown to be correlated to breeding.
We conclude that the climatic effect on puffins was mediated through their feeding conditions;
plankton and larval herring. Adverse oceanographic conditions in early spring when the
phytoplankton bloom occurs have a negative effect on puffin reproduction by degradation of the prey
availability for chick-feeding adults three months later. Indeed, the timing of the puffin's breeding was
influenced by the NAO (Fig. 3).
The breeding performance of this top predator provides useful indicators of the development and
dynamics of organisms at the lower trophic levels.
REFERENCES: 1. Anker-Nilssen, T. Food supply as a
determinant of reproduction and population development in
Norwegian Puffins Fratercula arctica. PhD Thesis, Univ.
Trondheim (1992);
2.Toresen, R. & Østvedt, O.J. Fish and Fisheries 1, 231-256
(2000);
3. Data from Aure, J. & Østensen, Ø. Hydrographic normals and
long-term variations in Norwegian coastal waters (Fisken Havet
1993) and Pers. comm. G. Ottersen;
4. Data on NAO can be obtain from the web site
http://www.cgd.ucar.edu/~jhurrell/nao.html#winter;
5. Hurrell, J.W., Kushnir, Y., Ottersen, G. & Visbeck, M. The
North Atlantic Oscillation: Climatic Significance and
Environmental Impact (Geophy. Monogr. 134, 2003);
6. Venables, W.N. & Ripley, B.D. Modern Applied Statistics with
S-plus, -3rd ed (Springer, New York, 1999).
a. Durant, J.M. Anker-Nilssen, T., Hjermann, D.Ø & Stenseth, N.C. Regime shifts in the breeding of an Atlantic puffin population Ecol. Lett. 7, online
(2004). b. Durant, J.M. Anker-Nilssen, T. & Stenseth, N.C. Trophic interactions under climate fluctuations: the Atlantic puffin as an example. PRSB
270,1461-1466 (2003). c. Durant, J.M. Anker-Nilssen, T. & Stenseth, N.C. Climate affects the Atlantic puffin through food-chain variation. In ms
* JMD was funded by a Marie Curie Fellowship of the European Community programme IHP-FP5 under contract number HPMF-CT-2002-01852. E-mail: joel.durant@bio.uio.no
Quantitative Ecosystem Indicators For Fisheries Management International Symposium, 31 March - 3 April, 2004, Paris, France