[MARMAM] New paper

Phillip.Clapham at noaa.gov Phillip.Clapham at noaa.gov
Fri Feb 26 13:45:48 PST 2010


The following paper was just published:

Zerbini, A.N., Clapham, P.J. and Wade, P.R.  2010.  Assessing plausible
rates of population growth in humpback whales from life-history data. 
Marine Biology DOI 10.1007/s00227-010-1403-y.

ABSTRACT  The rate of growth of any population is a quantity of interest
in conservation and management and is constrained by biological factors.
In this study, recent data on life-history parameters influencing rates
of population growth in humpback whales, including survival, age at
first parturition and calving rate are reviewed. Monte Carlo simulations
are used to compute a distribution of rates of increase (ROIs) taking
into account uncertainty in biological parameter estimates. Two
approaches for computing juvenile survival are proposed, which taken
into account along with other life-history data, resulted in the
following estimates of the rate of population growth: Approach A: mean
of 7.3%/year (95% CI = 3.5–10.5%/year) and Approach B: mean of 8.6%/year
(95% CI = 5.0–11.4%/year). It is proposed that the upper 99% quantile of
the resulting distribution of the ROI for Approach B (11.8%/year) be
established as the maximum plausible ROI for humpback whales and be used
in population assessment of the species. Possible sources of positive
and negative biases in the present estimates are presented and include
measurement error in estimation of life-history parameters, changes in
the environment within the period these quantities are measured, density
dependence or other natural factors. However, it is difficult to
evaluate potential biases without additional data. The methods presented
in this study can be applied to other species for which life history
parameters are available and are useful in assessing plausibility in the
estimation of population growth rates from time series of abundance
estimates.

Reprints (pdf) available from the first author (alex.zerbini at noaa.gov).


Phillip J. Clapham, Ph.D.
Leader, Cetacean Assessment & Ecology Program
U.S. National Marine Mammal Lab
Alaska Fisheries Science Center
7600 Sand Point Way NE
Seattle, WA 98115
phillip.clapham at noaa.gov





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