- Geographical scale of the assessment:
- Regional, Mediterranean Sea
- Contributing countries:
- Mid-Term Strategy (MTS) Core Theme:
- 2-Biodiversity and Ecosystems
- Ecological Objective:
- EO1: Biological diversity is maintained or enhanced. The quality and occurrence of coastal and marine habitats and the distribution and abundance of coastal and marine species are in line with prevailing physiographic, hydrographic, geographic and climatic conditions.
- IMAP Common Indicator:
- Common Indicator 5 (CI5): Population demographic characteristics (e.g. body size or age class structure, sex ratio, fecundity rates, survival/mortality rates related to marine mammals)
- Indicator Assessment Factsheet Code:
- Cetaceans: Species populations are in good condition: Low human induced mortality, balanced sex ratio and no decline in calf production.
- Monk Seal: Species populations are in good condition: Low human induced mortality, appropriate pupping seasonality, high annual pup production, balanced reproductive rate and sex ratio.
- State: Decreasing trends in human induced mortality.
- Pressure (cetaceans): Appropriate measure implemented to mitigate incidental catch, prey depletion and other human induced mortality.
- Pressure (monk seals): Appropriate measures implemented to mitigate direct killing and incidental catches and to preclude habitat destruction.
The objective of this indicator is to focus on the population demographic characteristics of marine mammals within the Mediterranean waters. Demographic characteristics of a given population may be used to assess its conservation status by analysing demographic parameters as the age structure, age at sexual maturity, sex ratio and rates of birth (fecundity) and of death (mortality). These data are particularly difficult to obtain for marine mammals, thus relying on demographic models, all of which make assumptions that may be violated in practice.
Monitoring effort should be directed to collect long-term data series covering the various life stages of the selected species. This would involve the participation of several teams using standard methodologies and covering sites of particular importance for the key life stages of the target species.
The preliminary classical tools for demographic analyses are life tables, accounting for the birth rates and probabilities of death for each vital stage or age class in the population.
Fin whale - Demographic models - commonly used in animal and plant populations - have been applied to marine mammals and cetaceans only in the recent years. Usually, two different approaches are used when dealing with demographic studies, based on static or cohort life-tables. A third approach refers to the use of mortality tables and provides detailed information about size⁄age and sex of dead individuals.
Available data on demography for Mediterranean marine mammals are rather scarce and fragmented and at present it is rather difficult to provide strong and robust evidence on baselines and changes over time in demographic parameters.
- Systematic and long-term photo-identification programs, jointly to the use of appropriate instruments to measure observed animals, would be essential tools to supply basic knowledge on population structure needed for conservation plans.
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