Growth portfolios buffer climate-linked environmental change in marine systems

Area of Science:

• Marine ecology
• Fisheries science
• Climate change impacts

Background:

• Increasing ocean productivity synchrony due to climate change can reduce fish population resilience.
• The role of within-population trait synchrony in marine species' adaptive capacity is poorly understood.
• Existing research primarily focuses on synchrony across populations, not among individuals within populations.

Purpose of the Study:

• To investigate changes in individual growth synchrony within Atlantic cod populations over a century.
• To determine if within-population growth synchrony is influenced by environmental conditions and climate variability.
• To explore the potential adaptive significance of growth synchrony and asynchrony in marine populations.

Main Methods:

• Analysis of century-scale time series of annual otolith growth data.
• Utilized 74,662 annual growth increments from 13,749 otoliths of Atlantic cod (Gadus morhua).
• Statistical examination of growth conformity among individuals within multiple Northeast Atlantic cod populations.

Main Results:

• Detected increasing conformity in long-term growth rates within five Northeast Atlantic cod populations.
• Observed that within-population growth synchrony correlates with favorable growth conditions and climate variability (East Atlantic Pattern).
• Found evidence of climate-linked, among-individual growth synchrony in other Northeast Atlantic marine species.

Conclusions:

• Within-population growth synchrony can increase under favorable conditions, potentially enhancing population productivity.
• Growth asynchrony in poorer years may represent bet-hedging, increasing resilience to environmental change.
• Synchronized growth dynamics may have a stabilizing, albeit unexpected, impact on marine population productivity facing large-scale environmental shifts.