In 'Stung,' Researcher Connects Jellyfish Blooms To Doomed Oceans
May 20, 2013 1:03 p.m.
Lisa-ann Gerswhin, Ph.D. is director of the Australian Marine Stinger Advisory Services and author of "Stung! - On Jellyfish Blooms and the Future of the Ocean"
ALISON ST. JOHN: You are listening to KPBS Midday Edition. I am Alison St. John in for Maureen Cavanaugh. Jellyfish are always fascinating for kids finding that washed up on the beach but recently they've been making some impressive. Mr. headlines lifeguards and as it is reported more than 130 swimmers were stung by jellyfish on just one Sunday. Also, last year, swarms of jellyfish clogged the cooling intake of the Diablo Canyon nuclear power plant near San Luis Obispo, forcing operators to shut it down. Never write these of jellyfish are showing more frequently on San Diego Shores so what is going on. Our guess and says the growth of jellyfish populations is dangerously out of control. So Dr. Lisa-ann Gershwin is director of the Australian Marine Stinger advisory services. She's just published a book called Stung on jellyfish blooms and the future of the ocean and she's in San Diego for an appearance at the Birch aquarium at Scripps this evening. Welcome
LISA-ANN GERSHWIN: Thank you so much. It's great to be back in Southern California.
ALISON ST. JOHN: Yes so now you're from Australia. I want to just ask, actually we were just talking about the fact that Australians appear to be a little bit ahead of the game, which is a that is true on issues related to global warming and the environment?
LISA-ANN GERSHWIN: Many of the issues, such as, I guess being more proactive about dealing with the issues and managing the issues, I think that is often true. But interesting in the issue of jellyfish blooms, America is way ahead of the game in terms of having the problems. There are many more problems where jellyfish blooms are impacting human endeavors here in America than in Australia.
ALISON ST. JOHN: Interesting. They've been around for 500 million years and they've been more of a curiosity than anything else and they seem pretty delicate creatures, but in your book you compare jellyfish to the angel of death, why?
LISA-ANN GERSHWIN: They are in many ways. They do this funny thing where, let me back up. We normally think of the food chain in fairly conventional terms, where large things eat small things, fast things eat small things, smart things eat dumb things, but jellyfish turn it all around and jellyfish actually, they are sort of low on the food chain, but the eat the eggs. Eggs and larvae of food chain of them themselves that they also eat the plant and that the larvae would eat, so they actually, with this double whammy of predation and competition. They are able to actually drive the perturbations or the stressors... I'm not finding the right words,
ALISON ST. JOHN: The stressors?
LISA-ANN GERSHWIN: So there's a little bit of an impact on an ecosystem, maybe a little bit of a wobble in the jellyfish are able to drive the wobble into a very serious problem. And we see this happening all around the world in many ecosystems.
ALISON ST. JOHN: You talked about how jellyfish are displacing penguins in Antarctica. How do they do that?
LISA-ANN GERSHWIN: Indeed, penguins eat lots and lots of krill and krill are on the decline partly because we are fishing and and partly because they are feeding, their feeding area is getting smaller. The krill eat the phytoplankton on the underside of the edges of the sea ice so, as the sea ice cover melts, there is less and less edge, right, the edge is getting smaller, so there is less available feeding grounds for the krill. The jellyfish called Soaps, a certain type of jellyfish are on the increase as the krill, or jellyfish are increasing and we see a flip to the ecosystem and the Penguins do not eat krill, sorry the penguins eat krill, not jellyfish
ALISON ST. JOHN: So we hear about polar bears being threatened but actually penguins are being threatened by jellyfish. Fascinating. Closer to home we had a story on KPBS just last year about plumes of black jellyfish that appeared only five times in the last 10 years in our local waters. And before that in nine previous 100 years they had been seen five times. And then there was this big blue (inaudible). Do you think there could ever be a point where we can no longer swim safely in the oceans.
LISA-ANN GERSHWIN: That's a really good question. Before you get to the point where we cannot swim safely. We will get to appoint where jellyfish are causing so many problems with decline in fish, clogging of nuclear power plants and desalination plants
ALISON ST. JOHN: That is relevant to us here.
LISA-ANN GERSHWIN: Pretty much where there's an intake for cooling water like this, the jellyfish are clogging up, so I think we may well get to a place where it is not safe to swim but I think we will get to another place, first that is much less desirable for us.
ALISON ST. JOHN: Why are they so difficult to deal with? There are just jelly after all can't they be dissolved?
LISA-ANN GERSHWIN: If only, if only. Look it's an interesting thing. They have what we call a biphasic lifecycle or a two-faced lifecycle with a polyp stage that is stuck to rocks and shells and the undersides of peers and whatever, that they have the jellyfish stage that we are more familiar with but the polyp stage occurs in such vast numbers underneath the water that they are just popping off little baby jellyfish not constantly, the weather conditions are good, constantly and they just form these vast blooms, so it's not a matter of dealing with the jellyfish exactly, it's a matter of dealing with the polyps as well and they are much harder to find.
ALISON ST. JOHN: What are some of the signs that the jellyfish are taking over the ocean as your book proclaims?
LISA-ANN GERSHWIN: Well, I think there are many ecosystems around the world where these ecosystems have flipped from being dominated by healthy fisheries and good grief systems and the types of ecosystems that we think of as healthy systems, they've actually flipped to being dominated by jellyfish. They scratched the fisheries. There are so many things where the jellyfish have actually taken over these ecosystems. It hasn't happened in every ecosystem, but it's happened in enough different ecosystems which different types of stressors that are at play that we can look at the pattern and say that does not look good.
ALISON ST. JOHN: The trend is kind of disturbing, yeah. What are some jellyfish predators, what happened to them?
LISA-ANN GERSHWIN: Unfortunately, we like to eat most of the jellyfish predators so there are fewer of those that there would like there to be. Sea turtles are one of the key predators. Crabs are one of the key predators. Certain types of fish, but only a few types of fish actually eat them. The bigger issue is not so much the predators as much as their competitors. Pretty much the small pelagic fish like sardines, the anchovies, those sorts of fish are the primary competitors and we are extracting those out of the oceans at unbelievable rates. That means that there is more available food for the jellyfish.
ALISON ST. JOHN: Are they getting bigger? You write that some of them are as big as a fridge, there are amazing photographs in your book.
LISA-ANN GERSHWIN: They are indeed, there are some that are very large. Most jellyfish are not getting bigger in actual size, they are limited like we are. We have a certain normal size for humans jellyfish species are the same way, but the populations are getting bigger and in many places, the season that they are in the jellyfish stages are getting better, so we are seeing longer blooms, larger blooms lasting over bigger areas and longer periods of time.
ALISON ST. JOHN: What do jellyfish eat?
LISA-ANN GERSHWIN: Just about anything but usually small. Most jellyfish eat plankton in the water so with little larvae and small crustaceans and little micro mollusks and things like that and the water, but they eat constantly. So they can actually filter eight vast, vast quantities of food. And they grow very very fast. Some jellyfish can actually eat up to 10 times their body weight per day in plankton.
ALISON ST. JOHN: This is the bottom of the food chain, which is why it's so significant.
LISA-ANN GERSHWIN: Yeah but they are at the bottom of the food chain but they are eating up the food chain. You're actually eating the eggs and larvae and plankton that are higher on the food chain than themselves. So it's a very interesting thing the jellyfish do.
ALISON ST. JOHN: Is there anything one can do with jellyfish to the tentacles of chemical properties?
LISA-ANN GERSHWIN: They probably do many jellyfish have really powerful toxins.
ALISON ST. JOHN: Some reason why, perhaps humans might be able to use them and hunt them. Because at the moment. I guess they are not really ever hunted.
LISA-ANN GERSHWIN: Some species of jellyfish are harvested for food, but particular species, not every species. We have not really explored their toxins very much for different pharmaceutical options, but sure it's there, they have very powerful toxins.
ALISON ST. JOHN: You started studying jellyfish back in 1992, what kind of reactions did you get when you said, I'm studying jellyfish and has the reaction changed?
LISA-ANN GERSHWIN: I don't know how well it will translate on radio but it pretty much was a very blank stare from most people. And if they uttered any words at all. It was kind of like, huh? People just could not believe I was studying jellyfish it was like why would you? Whereas now people go that's really interesting. So I think a lot of the awareness of jellyfish as a key component of ecosystem health and an indicator of ecosystem health, a driver of unhealthy ecosystems and I suppose something that is affecting us humans in ways that we didn't expect, and we do not want, and I think we are actually coming to see jellyfish as something we should be paying more attention to.
ALISON ST. JOHN: Is there more scientific research into it? We've got nuclear power plants being shut down because of it. Is there any money being invested into how to control the populations?
LISA-ANN GERSHWIN: There is some money being invested. I think maybe there's room for more, certainly, one has to, the money holders need to balance the priorities. But I think jellyfish are certainly bouncing up and down and flashing their tentacles all over the place saying look at me, look at me, they're definitely causing a lot of problems in a lot of places.
ALISON ST. JOHN: How do you know that the large jellyfish blooms are part not part of a natural cycle?
LISA-ANN GERSHWIN: They do bloom as a natural part of the lifecycle, so they are not doing anything that they don't normally do. That part is completely natural. What is not natural is that we are giving them the exact conditions that they need to do more of it. Warmer water makes that breed faster and grow more and grow more and faster, and extends the breeding and living and hunting season. We are giving them warmer water, fewer predators and competitors means that they don't have to struggle so hard to survive because not as many are getting eaten or dying of hunger and we are taking the predators and competitors. We are doing things, poisons and toxins in things that are unhealthy for fish, the jellyfish are sort of the me into it?
ALISON ST. JOHN: Why do they like acidic oceans?
LISA-ANN GERSHWIN: It's not that they like acidic oceans exactly. They just respond, they don't respond to it, put it that way. Whereas the predators and competitors tie off and jellyfish are kind of the last man standing.
ALISON ST. JOHN: I was just thinking we've seen a lot of male nurse to sea lion pups coming ashore recently. You think there's any connection between this increase in jellyfish and the food chain for the sea lion pups?
LISA-ANN GERSHWIN: I don't know.
ALISON ST. JOHN: It's a complex food chain
LISA-ANN GERSHWIN: I'm not too up on the Sea Lion situation. There's been a couple of issues around the world with large die offs of dolphins and things like that and the jellyfish have been suggested as a possible component. But I don't know of any studies that have demonstrated that it is or is not, but I think it's worth thinking about.
ALISON ST. JOHN: Would you think if anything can be done to modify this enormous increase in the population? You are saying it's out of control. Is there anything that can be done to control it?
LISA-ANN GERSHWIN: The really interesting thing is the jellyfish respond very quickly to environmental conditions. There have been a few success stories around the world where the conditions that enabled the jellyfish populations have been taken away and the jellyfish fall right away. They just disappear, go right back to being what we would call normal, that is not out of control, so there are some good success stories. The problem is, those conditions that we would need to take away are not things that most of us really want to do. We'd have to really illuminate the fishing. Would have to eliminate the warming. We have to eliminate the nutrients coming down the rivers from agriculture and the sewage effluence coming from the cities. Major changes would have to happen to the oceans and I think part of the problem is most humans have not connected the dots that the changes in the environment are biting us in the butt, can I say that? Biting biting us in the backside, I'm sorry. I think the problem is we haven't connected the dots to how it is affecting us, so we are not willing to make the changes because we don't want to pay higher taxes for cleaner energy and cleaner effluence. We don't want to have changes to the cost for fishing locally and all these things, we want what we want. We expect certain things. And we are willing to fight for them. But we don't realize that by having those things, we are chipping away at our future.
ALISON ST. JOHN: You have a couple of lines at the beginning of your book from the rime of the ancient barrier that goes until my ghastly tale is told, this heart within me burns. So you feel pretty passionately about this.
LISA-ANN GERSHWIN: I do. It was really a very formative process writing the book. When I first started writing the book, I thought that it was just kind of a nifty groovy story. I really didn't realize how serious we have damaged our ecosystems and it was while I was writing the book and reading up on all these things that I've known about for a long time, pollution, overfishing, introduced species, yada yada yada and I know about these, I'm a marine biologist, have been for many years but it was as I was reading up on them in the latest literature that I started realizing, oh my God, this is really serious. This is really, really serious. And that jellyfish are not only the visible indicator of that problems but the inheritor. They are what is left over when all the problems have taken their toll. So, when I started writing the book thinking it was cool. I ended the book thinking all my God, this is really serious.
ALISON ST. JOHN: Well you have left us with something to think about here, Lisa, thank you so much for joining us.
LISA-ANN GERSHWIN: Pleasure
ALISON ST. JOHN: Dr. Lisa-ann Gershwin is president of the green stinger services you speaking to me at the Birch aquarium at Scripps at 6:30 for a public evening lecture.