You feeling the burn? The black jelly, or black sea nettle. Photo: Wikimedia Commons via Monterey Bay Aquarium.
Most days when you paddle out into the ocean, the water fully refreshes you. As glassy waves wash over your board and body, any worries or irritants seem to fade away, falling with the tides.
And then there are the other days. The days when you paddle out and your skin feels an immediate irritation. A mildly-itchy, slightly-stinging sensation that seeps into your wetsuit and rests on your forehead and cheeks, flaring between sets. You surf your way through the session because, of course you do, but leave the lineup excited to rinse the salty sea off. Perhaps this is a result of the sunscreen you forgot to re-apply last weekend, but more likely than not, this itch is from exposure to blooms of microscopic jellyfish larvae. A common and relatively harmless occurrence, but an uncomfortable one.
While acidification, rising ocean temperatures, and pollution are impairing most marine species, these changes are actually aiding jellyfish expansion and creating an ideal environment for jellies to thrive in. The West Coast sees several species, like the Pacific sea nettle or black sea nettle (black jelly), that have reportedly clogged up Orange County beaches before . For the majority of marine life, plastic pollution can result in entanglement, suffocation and debris-filled stomachs that lead to starvation. For jellyfish, more plastic means more opportunity for survival during some critical stages of their formation.
The lifecycle of a jellyfish is a bit more complex than one may expect of a boneless, brainless, bloodless creature. The distinctive bell-shape that we all envision when we think “jellyfish” is from a late phase of a jellyfish’s lifetime, known as the “medusa phase.” At the beginning of their lives, jellies have been asexually produced as tiny larvae and float along with the tides for a while…often drifting into your wetsuit…and after some maturing, these tiny larvae undergo a radical change, cycling into their “polyp” phase. Think of it as their rebellious teenage years (it’s just a phase, mom).
During this polyp phase, the jellies must attach themselves to a surface or “substrate” in order to grow. Under natural circumstances, these polyps will settle into the ocean floor. But as man-made surfaces such as plastics infiltrate the seas, jellies are provided with other materials to attach to. In consequence, jellyfish are able to thrive in deeper water, no longer needing to remain on the coastlines or endure great depths to reach a substrate. Thus, expanding their populations and range.
Through the crisp winter months of 2019, an expedition ship filled with marine biologists braved twenty-foot swells across the Gulf of Alaska to record changes in the salmon population. But what ended up defining the voyage was a massive, wildly unanticipated bloom of jellyfish, or more precisely, a giant cluster of northern sea nettle.
Canadian oceanographer Brian Hunt, who was the primary observer of these jellyfish blooms, spent 11 nights of their journey on the ship’s deck, counting the species typically native to shallow water through visual observation. Overall, Hunt estimated that the ship passed some 10 million tons of displaced jellyfish.
As one of the most opportunist species on Earth, jellyfish have both adapted to, and thrive in, environments and degraded ecosystems in which other species cannot. According to fossil and sediment records, jellies are one of the only animals to have survived every mass extinction in Earth’s history since their evolution. Because they are boneless, pH imbalances in the ocean do not negatively affect the jellies in the way that it affects marine species with skeletal structures. And because rising temperatures have such drastic effects on other species, the uninfluenced jellyfish are able to outcompete their adversaries, such as salmon, for food.
All this to say, it’s not the jellyfish’s fault. These brainless beings are simply adapting to an environment that is shifting in their favor.
Higher temps, increasing acidification, more plastic…more jellies. So the next time you go to order that fun new set of flip flops that ships in plastic packaging, consider that down the line the outcome may result in more itchy-skinned surfs and a greater presence of the big, stinging jellies.
