Australia barely had time to recover from record breaking fires at the start of 2020 before the Great Barrier Reef experienced its third mass coral bleaching event in the past five years. Only five of these have occurred since records began in the 1980s. High water temperatures and marine heatwaves, caused by climate change, are making coral bleaching an almost regular occurrence in some parts of the world.
Coral reefs are among the most vibrant ecosystems on the planet, but they are also very sensitive to stress. Meteorologists predict that 2020 is likely to be the hottest year on record, threatening yet more bleaching on reefs around the world. But it’s not just the coral itself that suffers.
Reef fishes exposed to high temperatures tend not to behave normally. Underwater noise and pollutants, such as agricultural pesticides, can have the same effect. Juvenile fish exposed to this kind of stress are less able to identify and avoid predators. But scientists aren’t sure exactly why this is. MORE
Header image: High temperatures and pesticides can disrupt sensory development in young fish. Credit: Aldine Amiel/Kahi Kai, Author provided.