Climate change and fish species decline – A new study led by Dr Angus Atkinson of PML (Plymouth Marine Laboratory) has revealed a silent threat beneath the waves: climate change is significantly eroding the ocean’s ability to provide fish. The findings, published in Nature Communications, reveal a hidden amplification mechanism within the marine food web, highlighting the vulnerability of our marine ecosystem.
Phytoplankton decline and the food chain
At the heart of the problem lies the even small decreases in phytoplankton caused by global warming. When phytoplankton levels decrease by only 16-26%, as predicted by global models, there is a 38-55% drop in the carrying capacity of fish. This amplification phenomenon is the result of a longer and inefficient food chain, which has crucial implications for global fisheries.
The role of phytoplankton and the discovery
Contrary to expectations, temperature is not the main culprit. The key lies in the overall amount of phytoplankton, which determines the efficiency of energy transfer through the food chain. The warming of the oceans indirectly affects fish, reducing the supply of nutrients from deeper waters, changing the size of phytoplankton and compromising energy flow.
Dr Atkinson emphasises the urgency of considering climate change in fisheries management, pointing out that global averages can mask real threats, with some of the most significant declines in concentrated fishing areas. The team’s global analysis reveals a hidden vulnerability that requires a multi-pronged approach to ensure sustainable fisheries in the face of climate change challenges.
Climate change is triggering a dangerous ripple effect in the oceans, threatening the viability of global fisheries. Understanding the hidden amplifiers within the food web is crucial to protecting the future of our oceans and the vital resources they provide. Research highlights the need for climate-smart strategies that combine data on plankton size structure and sophisticated computer simulation models to preserve marine resources.
Climate change and fish species decline