Synergistic effects of fishing-induced demographic changes and climate variation on fish population dynamics
Hidalgo, Manuel; Rouyer, Tristan; Molinero, Juan Carlos; Massutí, Enric; Moranta, Joan; Guijarro, Beatriz; Stenseth, Nils Christian
Journal article, Peer reviewed
Permanent lenke
http://hdl.handle.net/11250/109138Utgivelsesdato
2011-03-28Metadata
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Originalversjon
http://dx.doi.org/10.3354/meps09077Sammendrag
The synergistic effects of fishing, climate
and internal dynamics on population fluctuations are
poorly understood due to the complexity of these interactions.
In this paper, we combine time series analysis and
simulations to investigate the long-term dynamics of
an overexploited population in the Mediterranean Sea,
and its link with both fishing-induced demographic
changes and hydroclimatic variability. We show that the
cyclicity of the catch per unit of effort (CPUE) of European
hake Merluccius merluccius (EH) vanished in the
1980s, while the correlation between the CPUE and a
local environmental index increased. Using simulations,
we then show that the cyclicity observed in the EH biomass
before the 1980s can have an internal origin, while
that its disappearance could be due to the fishinginduced
erosion of the age structure. Our results suggest
that fishing can trigger a switch from internally generated
to externally forced population fluctuations, the
latter being characterised by an increasing dependency
of the population on recruitment and ultimately on environmental
variability. Hydroclimatic modifications occurring
in the Mediterranean in the early 1980s could
have enhanced these changes by leading to a mismatch
between early life stages of EH and favorable environmental
conditions. Our conclusions underline the key
effect of the interaction between exploitation and climate
on the dynamics of EH and its important consequences
for management and conservation.