Warm temperatures, low river flows and declining water quality are sparking fears of another mass fish die-off in the Cowichan River this summer. The Cowichan Watershed Board said river conditions this summer “mirror” those of 2023, when an estimated 84,000 to 100,000-plus fish died after prolonged drought and heat. Samples recently collected from six points along the Cowichan River show the water is seeing significant daily fluctuations in pH and dissolved oxygen levels similar to those of 2023. …Weir flows were reduced this spring so more water could be maintained in the summer. Researchers are also looking to identify, protect and improve cold-water refuge areas along the river that could provide fish a respite from the heat when waters warm. …Built in the 1950s to provide water for the pulp mill at Crofton, the Cowichan weir is owned and operated by Domtar.