Billions of Dead Jellyfish Washing Up Worldwide: What’s Happening?

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• FAQs

In recent years, beaches across the globe have been inundated by billions of dead jellyfish, creating what experts describe as a “crunchy carpet” of corpses. These mass strandings involve a specific type of jellyfish known as Velella velella, also referred to as “by-the-wind sailors.” While the phenomenon may seem shocking, understanding the reasons behind these events reveals important insights into marine ecosystems and the potential impact of climate change effects on oceans.

What Are Velella velella Jellyfish?

Velella velella are unique jellyfish that thrive in large colonies, often consisting of millions of individuals or more. These jellyfish are equipped with small, sail-like structures that allow them to drift along ocean currents and winds. They are typically harmless to humans, and their translucent blue bodies are often a spectacle to behold at sea.

However, this reliance on wind and currents for movement makes them vulnerable to changing weather patterns. Seasonal wind shifts can drive these colonies toward the shore, where they become stranded. Once on land, they dry up and die, leaving behind a brittle, crunchy layer of corpses. Such Velella velella strandings are becoming more common due to climate change effects on oceans.

Notable Stranding Events

Large-scale Velella strandings are not new, but their frequency and magnitude have drawn increasing attention. Some significant events include:

• 2006: Millions of Velella washed up on beaches in New Zealand.
• 2015: Approximately one billion dead jellyfish were stranded on the west coast of the United States.
• 2015 to 2019: The largest recorded mass jellyfish strandings occurred along the U.S. Pacific Coast, coinciding with a marine heat wave known as “the blob.”

The Role of “The Blob” and Climate Change

“The blob” was a period of unusually warm ocean surface temperatures that affected the Pacific Ocean from 2015 to 2019. Studies based on 20 years of citizen-science observations have linked these marine heat waves to increased Velella velella strandings.

Warmer waters during the blob extended the spawning season of certain fish, leading to an abundance of plankton, the primary food source for Velella velella. This abundance likely fueled jellyfish population booms in Velella, resulting in massive strandings when winds shifted.

While beneficial for these jellyfish, the blob disrupted marine ecosystems, causing die-offs in other species. As climate change intensifies and marine heat waves become more frequent, it’s likely that Velella strandings will become more common and even larger in scale.

Why Does It Matter?

Mass strandings of Velella jellyfish serve as a stark reminder of the interconnectedness of marine ecosystems and the effects of climate change. While the sight of billions of dead jellyfish washing ashore can be fascinating, it’s also a signal of broader ecological changes.

FAQs

1. Are Velella velella dangerous to humans? No, Velella velella are harmless to humans. They lack the potent stingers of other jellyfish species, though some people may experience mild irritation if they come into contact with them.

2. Why do Velella velella wash up in such large numbers? These jellyfish rely on winds and currents for movement. When seasonal winds shift, they can be driven toward shorelines, resulting in mass jellyfish strandings.

3. What happens to the jellyfish after they wash ashore? Once stranded, Velella velella dry up and die, leaving behind a brittle, crunchy layer of corpses.

4. How is climate change influencing these events? Climate change increases the frequency of marine heat waves, such as “the blob” heat wave, which create conditions favorable for Velella population booms. These booms, combined with wind shifts, lead to larger and more frequent strandings.

5. Can these events harm the environment? While Velella strandings are natural, the conditions leading to them—such as marine heat waves—can disrupt marine ecosystems, affecting other species and altering food webs.