St Aubin's Bay has experienced a summer free from the dense green sea lettuce blooms that have previously affected the popular coastal area. Officials attribute this change to a combination of unusually high spring temperatures and successful efforts to reduce nutrient runoff from agricultural land.
Sea lettuce typically reproduces in May, but the Environment Department spokesperson indicated that the exceptionally warm weather during that period likely disrupted its normal growth and reproductive cycles. Jersey recorded its hottest May day on record this year, with temperatures reaching 29.2 degrees Celsius (84.5 degrees Fahrenheit), and these elevated temperatures persisted through the summer.
Alongside the climatic factors, the government noted that initiatives by the Action for Cleaner Water group and the agriculture industry to reduce nitrate use on fields have contributed to mitigating the build-up of nutrients in the bay. Action for Cleaner Water is a collaborative project involving Jersey Water, the government, and representatives from Jersey's farming and dairy sectors, aimed at enhancing water quality.
Previously, nutrients from various sources, including agricultural runoff containing fertilizers and treated wastewater from treatment works, were identified as significant contributors to sea lettuce proliferation in the bay. In past years, harvested sea lettuce was repurposed for use on island fields; nearly 3,000 square meters of lettuce was removed for this purpose in 2025.
The absence of the seaweed this year has provided a welcome respite for the bay, which is a popular location for recreation.