Are we heading towards a global decrease in coregonine catches? 6
Coregonine catches declined in 67% of the 27 lakes studied across three continents in the Northern Hemisphere during the first two decades of the 21st century, with 44% showing significant trends. The analysis showed that lakes with significant catch declines were larger and nutrient-poor. The rate of change in catch appeared to be related to the trophic state of the lake, with oligotrophic and ultra-oligotrophic lakes experiencing the largest declines. While local factors such as nutrients, invasive species and fishing practices contribute to declines, the study suggests a global link between trophic state and coregonine catch trends, influenced by climate change and lake size. The results highlight a potential conflict between water quality management objectives and coregonine fisheries productivity. Efforts to achieve pristine water conditions in developed countries may reduce the productivity of coregonine fisheries. The study highlights the need for collaboration between water and fisheries managers to establish lake-specific management objectives that address the needs of all lake users, particularly in the face of increasing climate change impacts and the introduction of invasive species.