The stark images of starved seabirds washing up on California's sun-kissed beaches have left marine ornithologists and conservationists grappling with the dire consequences of a prolonged marine heatwave. The situation is being exacerbated by the official declaration of El Niño, which will amplify global weather patterns and further disrupt the delicate balance of marine ecosystems.
Tammy Russell, a postdoctoral scholar at the University of California, San Diego's Scripps Institution of Oceanography, has witnessed firsthand the devastating impact on seabird populations. Her recent surveys along San Diego beaches have uncovered numerous bird carcasses, with many species succumbing to starvation due to record-breaking ocean temperatures.
The scarcity of cold, nutrient-rich surface water is having a direct impact on the availability of krill, anchovies, and sardines – the primary food sources for seabirds. This has led to an unprecedented surge in bird fatalities, with California brown pelicans, loons, and grebes among those affected. Russell's observations have also revealed cormorants collapsing and dying on shore within minutes, a phenomenon she describes as "shocking".
The current marine heatwave off the US west coast has been ongoing for over a year, marking only its third occurrence in recorded history. Daily ocean temperature measurements at Scripps Institution of Oceanography's 10 coastal stations have shown three breaking records for over 40 days this year, while robotic underwater gliders have registered abnormally high temperatures offshore and at depth.
The combined effect of the marine heatwave and El Niño is expected to wreak havoc on marine food webs, with far-reaching consequences for a wide range of sea life. As cold-water species migrate in search of cooler waters, seabirds will be forced to venture further afield in pursuit of sustenance. The impact on wildlife rehabilitation facilities in California has already been significant, with hundreds of emaciated birds treated this spring.
JD Bergeron, CEO of International Bird Rescue, notes that the situation is reaching crisis point. "We're seeing an unusual number of dead birds washing up on our shores, and brown pelicans are appearing in inland lakes – a desperate attempt to find food," he warns. The consequences of this unfolding disaster will be felt not just in California but across the globe, highlighting the urgent need for concerted action to mitigate the effects of climate change.