Publication Abstract

Using elasticity, perturbation analysis, demographics and elasmobranch species phylogenic relationships as indicators of vulnerability to exploitation

Using elasticity, perturbation analysis, demographics and elasmobranch species phylogenic relationships as indicators of vulnerability to exploitation

M.G. Frisk, N. Dulvy and T.J. Miller

Using exiting data from the literature for elasmobranch species we: (1) used stage-based population models and elasticity analyses to determine how the vital rates of mortality (M) and fertility (f) influence population growth rate (r), (2) determined the response of elasticity to changes in the levels of exploitation, (3) used model inputs and species vital rates, such as size maturity (L_mat), and total length (L_max), and phylogenic associations, as indicators of potential acceptability to over exploitation, and (4) estimated the effects on elasticity of perturbing model vital rates. We found a negative association between species size and elasticity of inter-stage transitions and a positive relationship between species total length and elasticity for adult and juvenile stages of the models. We found that there were no clear associations between trends in elasticity and phylogenic groupings. However, when reproductive modes and vital rates were added weak associations were found between species phylogenies and population dynamics.

Reference:

M.G. Frisk, N. Dulvy and T.J. Miller, 2002. Using elasticity, perturbation analysis, demographics and elasmobranch species phylogenic relationships as indicators of vulnerability to exploitation. NAFO SCR Doc., No. 02/111. 18p.

M.G. Frisk, N. Dulvy* and T.J. Miller

NAFO SCR Doc., No. 02/111. 18p