Harvesting and Population Structure Effect on Population Growth

Population dynamics of marine fishes has been the focus of considerable research particularly in relation to climate change and harvesting. However many functional mechanisms remain a mystery. Population growth is affected by several factors such as climate, species interaction, and harvesting pressure, the last having been shown to make the marine populations more sensitive to climate forcing. The juvenated populations are a worldwide consequence of the protracted size-selective mortality of commercial fishing on the older and larger individuals. This process may also increases a populations’ ability to directly respond to environmental fluctuations, emphasizing the importance of the interaction between fisheries, environment and internal dynamics that produces complex synergic effects on the population dynamics of marine species.

            We used a comparative approach investigating commercially fished species on an Arcto-boreal system: the Barents Sea. Our objective was to address the ecological consequences of fisheries effect on population properties (intrinsic growth rate) in relation to different external conditions (fishing intensity or climate). For this, we have applied techniques based upon age-structured population matrices to analyze estimated stock sizes. We investigated differences in the coupling between life history traits and population dynamics for all stocks that display different level of juvenescence.