Fish populations are influenced by climate change through various mechanisms operating across different life-history stages and ecological processes within ecosystems. For example, factors like temperature, oxygen levels, salinity, and ocean pH affect successive life stages of fish (eggs, larvae, juveniles, adults) uniquely. The responses of fish to these changes play a critical role in shaping population dynamics and ecosystem-level processes.

Species-specific responses to temperature changes are revealed by eco-physiological data, impacting habitat suitability and interactions among species. For instance, temperature changes can disrupt trophic relationships, causing shifts in predation patterns and species interactions. Different species and species-groups exhibit varying degrees of sensitivity to temperature shifts, which can alter community dynamics and food web structures. Understanding these sensitivities is essential for predicting how climate change will impact fish populations and overall ecosystem stability.

Climate change also affects vital rates and productivity of fish populations, with early life-history stages being particularly vulnerable. Changes in ocean conditions over (multi-)decadal scales influence growth, mortality, and recruitment rates, ultimately shaping the productivity of fish stocks. Additionally, climate-driven shifts in growth rates of recruited life-history stages may impact fish productivity, potentially altering intra- and interspecific competition for resources like food.

An integrated approach that considers all life stages and ecological processes is necessary to fully comprehend the impacts of climate change on fish populations. Formulating testable hypotheses based on ecological characteristics and life-history traits helps predict species’ responses to climate change. Moreover, studying distributional shifts in fish species provides insights into broader changes in fish assemblages and ecosystem dynamics. For example, pelagic species often exhibit stronger responses to climate change compared to demersal species, which may lead to significant shifts in community composition and ecosystem structure. Overall, a comprehensive understanding of how climate change affects fish populations is crucial for effective management and conservation of marine ecosystems in a changing environment.

References

Rijnsdorp, Adriaan D., et al. “Resolving the effect of climate change on fish populations.” ICES Journal of Marine Science, vol. 66, no. 7, 2 Apr. 2009, pp. 1570–1583, https://doi.org/10.1093/icesjms/fsp056. Date Accessed: 4/15/2024