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Part B: Literature and models available

Key questions

  • Two projects were funded that addressed the following key question:
  • Does the relationship between population vital rates and population dynamics provide any insight into the demographic parameters (e.g. sex or age group) that should be considered in the risk management process?

Summaries

Project 1 (NOVA) was a comprehensive literature review and modeling effort to determine which vital rates are most important for determining the growth and sustainability of marine mammal populations, and how much each vital parameter can change before a change in population trend would be expected. Project 2 (CREEM) was a modeling exercise that successfully incorporated life functions and behaviour into existing models of population dynamics that did not consider these variables.

The literature review project indicated that most large whale populations appear to be most sensitive to changes in adult female survival and secondarily to juvenile survival and growth. The modeling project provided a theoretical summary of mathematical and statistical models that could be used to predict how changes in behaviour may impact population dynamics. Both projects identified sensitivity and elasticity analyses as useful first steps in identifying proper management focus.

Objectives and methods

  • The objective of Project 1 was to review the data available (terrestrial and marine) on the relationship between vital rates and population dynamics.
  • The objective of Project 2 was to modify existing models for population dynamics in marine mammals so they may include the effects of animal behaviour and life functions on vital rates.

Importance

Project 1

Suggested that industry should focus research on the effects of industry noise on adult female and juvenile survival, and use existing data to develop the relationship between vital rates and/or behaviour and population effects. Project 2 succeeded in incorporating behaviour into a population model, and showed that reliance on models can help defray the costs and difficulty of gathering new data.

Both projects contributed to further improvement and development of the PCAD model by a panel funded by the U.S. Office of Naval Research. Project 1 contributed data, and Project 2 contributed the population model that served as the basis for four other models that this panel created for different marine mammal species.

Go to the ONR website.

Links to other research

  • Project 1: No other literature search was conducted on this topic.
  • Project 2: See the link to the ONR website above.

Institutions/PIs

  • Project 1: NOVA Southeastern University, Florida (Edward Keith)
  • Project 2: CREEM, University of St. Andrews, Scotland
    (John Harwood).

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