In the panoramic vista of the UK’s aquatic territories, there has been an unprecedented spike in jellyfish sightings. A recent survey by the Marine Conservation Society has revealed a 32% surge in jellyfish presence on beaches and within waters over the year.
Among the noted species, the colossal barrel jellyfish has become a frequent sight. However, sporadic appearances of the exotic warm-water crystal jellyfish have also been observed in the survey. Intrinsically waxing and waning over time, the jellyfish population’s burgeoning growth is attributed to the climate’s escalating warmth nurturing these creatures.
In fact, during a marine heatwave that occurred in June, it was noted that UK water temperatures underwent a 3-4C surge. This climate fluctuation coincides with global warming trends, with the world currently 1.1C warmer than the pre-industrial era, a sobering statistic leading to widespread apprehension among the scientific community.
The Society’s yearly wildlife reportension derives its data from citizens employing online platforms and apps for reporting their sightings. The period from October 2022 to September 2023 witnessed an impressive 32% rise in jellyfish sightings than the preceding year. A majority of these were observed along the UK’s west coasts, predominantly in Cornwall and Wales, with 11% constituting large swarms exceeding the count of a hundred.
The gargantuan barrel jellyfish, eloquently dubbed the “dustbin-lid” jellyfish, boasts a 1m (3ft) in diameter size. Their distinct feature is eight thick frilled arms, as opposed to the usual tentacles. The recent times have seen a whopping 467 sightings of this species. Other species like the Lion’s mane, Portuguese man o’ war, moon, and compass jellyfish have also been documented.
Members of the public have been requested by the Marine Conservation Society to report jellyfish sightings for the past two decades. These spiking figures could potentially indicate a 20-year cyclic pattern of growth and depletion, as per Dr. Peter Richardson. He expressed the significance of the survey in understanding the implications of climate change on our marine ecosystem.
Agreeing with this perspective, Dr. Abigail McQuatters-Gollop, a University of Plymouth plankton expert, observed an unprecedented abundance of jellyfish this year based on her daily diving experiences in August. She reported numerous sightings of the crystal jellyfish, a normally warm-water species, indicating the impact of increasing temperatures.
She asserts the successful proliferation of native jellyfish this summer could indicate the commencement of “tropicalisation of the oceans” due to climate change. However, she admits to the need for more research to ascertain if these high numbers are a result of long-term natural trends or marine heatwaves.
Future predictions suggest that the perennial warming of UK seas could transform the nation’s fish stocks, as the nourishment essential for fish species like cod could evolve.
The survey also brought to light sightings of twelve turtles, with four being the largest sea turtle, the leatherback.