Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Frequency responses of age-structured populations: Pacific salmon as an
  example   Increasing evidence of the effects of changing climate on physical ocean
conditions and long-term changes in fish populations adds to the need to
understand the effects of stochastic forcing on marine populations. Cohort
resonance is of particular interest because it involves selective sensitivity
to specific time scales of environmental variability, including that of mean
age of reproduction, and, more importantly, very low frequencies (i.e.,
trends). We present an age-structured model for two Pacific salmon species with
environmental variability in survival rate and in individual growth rate, hence
spawning age distribution. We use computed frequency response curves and
analysis of the linearized dynamics to obtain two main results. First, the
frequency response of the population is affected by the life history stage at
which variability affects the population; varying growth rate tends to excite
periodic resonance in age structure, while varying survival tends to excite
low-frequency fluctuation with more effect on total population size. Second,
decreasing adult survival strengthens the cohort resonance effect at all
frequencies, a finding that addresses the question of how fishing and climate
change will interact.

25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex