Can we project changes in fish abundance and distribution in response to climate?

Area of Science:

• Marine ecology
• Fisheries science
• Climate change impacts

Background:

• Climate change significantly impacts fish abundance and distribution globally.
• Fisheries management requires accurate, short-term projections at regional scales, validated by empirical data.
• High-resolution, long-term fish survey data offer a valuable resource for model validation.

Purpose of the Study:

• To assess the accuracy of bioclimate envelope models in simulating fish distribution and abundance changes.
• To evaluate model performance across different spatial scales using a 26-year North-East Atlantic fish survey dataset.
• To determine the influence of ocean model resolution and biogeochemical model fidelity on fisheries simulations.

Main Methods:

• Utilized a dynamic bioclimate envelope model forced by outputs from eight ocean models.
• Simulated fish abundance and distribution changes at spatial resolutions down to 0.5°.
• Compared model simulations against annual fish survey data from the North-East Atlantic.

Main Results:

• Largest discrepancies between model simulations and survey data occurred at the finest spatial scale (0.5°).
• Model-data differences decreased substantially when results were aggregated to larger scales, total catches, or ensemble means.
• Improved biogeochemical models led to reduced errors in fisheries simulations, though predictions often remained more similar to each other than to survey data.

Conclusions:

• Bioclimate envelope models can inform fisheries management at broader spatial scales.
• Greater caution is necessary when applying model results for fisheries management at finer spatial resolutions.
• Continued improvements in oceanographic and biogeochemical models are crucial for enhancing the reliability of fisheries projections.