Yearly, on beaches all over the world, colonies of Sailor jellyfish turn stranded by the thousands. There, they dry up and die in those sites, turning out to be what’s described as a ‘dry carpet’ of dehydrated bodies that cover the sand.
By Marie Morales
A new study recently showed millions of dead sailor jellyfish are worldwide, and ‘the blob’ could be blamed for such an occurrence.
Yearly, on beaches all over the world, colonies of jellyfish turn stranded by the thousands. There, they dry up and die in those sites, turning out to be what’s described as a ‘dry carpet’ of dehydrated bodies that cover the sand.
This was what professor and a new study, Velella strandings co-author Julia Parish, from the University of Washington, said in a Live Science report.
Sailor jelly strandings are typical when seasonal winds change course, although some, like an event that took place in 2006 on the west coast of New Zealand, are on another level completely, with the jellyfish dead bodies totaling not in thousands but the millions instead.
The reason for such an occurrence and what force of nature is making some Velella strandings so much greater than others is what the researchers were trying to find out in their study.
20-Year Observations of Velella
Like a tourist aboard a cruise ship, the by-the-wind sailor jellyfish, also called Velella velella, is spending its days aimlessly wandering through an open sea, gorging itself on what this science report described as an “endless buffet of complimentary morsels.”
The jelly is straddling the surface of the ocean with an inflexible sail punching just above the water and a collection of purple tentacles hanging just beneath.
As the sail is catching the wind, the jelly floats from place to place, catching small fish and plankton anywhere it roams.
Thriving colonies of Velella can comprise millions of individuals, all just apparently partying and chowing down together in the open water.
Until that’s the wind, blowing a cluster of sailor fish into shore. Parrish, together with her colleagues, wanted to find out. Therefore, in their new study, which the Marine Ecology Progress Series journal published, they investigated 20 years of observations of Velella, reported along the west coast of the United States.
The ‘COASST’ Program
These observations came from the Coastal Observation and Seabird Survey Team or COASST, a program training citizen scientists to look for their local beaches for marine birds that have washed ashore and any other unusual sightings of animals.
According to the group’s website, the network of COASST covers hundreds of beaches that stretch from northern California through the Arctic Circle. And certainly, some members had the so-called ‘run-ins’ with Velella.
The stud authors found that almost 500 reports of Velella strandings in the database of COASST, sighted on almost 300 beaches.
Based on these reports, the most massive die-offs took place during the spring months from 2015 until 2019. The researchers discovered that dead jellyfish littered over 620 miles or 1,000 kilometers of continuous coastline during the said years.
‘The Blob’
According to the science information site, the said jellyfish die-offs coincided with the so-called ‘the blob,’ a massive marine heatwave.
In 2013, the report specified that surface water off the Pacific coast started to heat up to levels that were never recorded in the past.
The strong warming continued until 2016, tampering with each level of the marine food chain and leading to mass die-offs of sea lions, seabirds, baleen whales, and other creatures.
This new study specified that it is possible that the blob draws the mass die-offs of by-the-wind sailor fish reported in the years mentioned.
The catch is, those warming ocean waters may have, in fact, been good for the jellyfish, according to the study authors. As the ocean’s blob increased surface temperatures, certain fish like northern anchovies benefited from a longer spawning season, providing more food for Velella jellies to eat up earlier in the year.
They may have caused jellyfish populations to spike before seasonal wind changes drove the jellies ashore in the spring.
Originally published at The science times