Premieres Wednesday, Oct. 26, 2022 at 9 p.m. and Sunday, Oct. 30 at 2 p.m. on KPBS TV + Oct. 30 at 9 p.m. on KPBS 2 / PBS Video App
NOVA “Ocean Invaders” explores the fascinating rise of invasive species in a globalized world where human activity has become an increasingly powerful evolutionary force. It dives deep into understanding one massively destructive species that has taken our oceans by storm — the lionfish. Native to the South Pacific and Indian Oceans and long prized in home aquariums, lionfish have invaded the Atlantic, and are now one of the ocean’s most successful invasive species, wreaking havoc in waters across the globe.
The film follows ocean explorer Danni Washington on her journey to answer the essential questions: What has made lionfish so successful at invading? Why are they doing so much damage? Where did they come from? What, if anything, can we do about them? Danni consults experts including marine biologists Carole Baldwin and Luke Tornabene, and endangered species expert Frank Mazzotti, who each share their unique expertise.
With striking striped bodies and an array of 18 venomous spines, lionfish are as spectacular as they are dangerous. Lionfish natively occur throughout the Indo-Pacific oceans, where they have a number of naturally occurring predators. In those areas, lionfish are regarded as a beautiful ornamental species, not as a nuisance that doesn’t belong. While the lionfish’s beauty is what helped make them popular in home aquariums around the world, most scientists believe that is also what ultimately led to the Atlantic invasion.
The prevailing theory is that in the 1980s, lionfish living in home aquariums were released off the coast of Florida. Over the next few decades, they began proliferating up and down the Atlantic coast and Caribbean. They are now widespread from North America all the way down to Brazil — there are even records of lionfish in the Mediterranean, introduced separately via the Suez Canal. Short-circuiting the geographic barriers between species is not new — for millennia, humans have managed to move plenty of animals to opposite ends of the earth. So what sets lionfish apart, allowing them to proliferate so rapidly in their new territory?
Lionfish have a suite of characteristics that make them a particularly successful invasive species. Their appetite is seemingly endless — they eat more than 100 different marine species, and can devour 90% of their body weight in a day. While most native fish only reproduce for a few months, female lionfish can produce millions of eggs over the entire year. And perhaps most importantly — in their non-native habitat, there aren't any animals who are used to seeing them as food. So without predators to keep them in check, lionfish have an unfair advantage.
But why is an animal thriving in a new territory a problem? “Ocean Invaders” takes a step back from lionfish to investigate the sometimes-confusing way that species are labeled “invasive.” By taking a closer look at terrestrial invasions from species like the terrifying Northern Giant Hornet in Washington state, European honeybees in North America, and even pet cats, it becomes clear that the threshold for earning the label comes down, in large part, to the extent a species is disrupting ecosystems at this moment in time. And to avoid having an invasive species irreparably shift the balance of an ecosystem, early detection and rapid response is key. Once an invasive species becomes established, the amount of money and resources needed to eradicate it are too costly.
Now, lionfish are well established in many parts of the Atlantic, and they are dramatically impacting the marine food web in those ecosystems. In some places, lionfish are killing off up to 80% of small, young fish. In some Atlantic waters, they even make up nearly 40% of the total predator biomass, whereas not long ago they made up 0%. In parts of the Atlantic, lionfish’s increased abundance has coincided with significant decline in many different prey fish.
Many of these species play crucial roles in the survival of corals. For instance, if lionfish continue to over-consume important players that keep algae growth in check, reefs could suffocate. From fishing to tourism, the lifeblood of countless coastal communities in the Western Atlantic that depend on coral reefs could be at risk. These threats are what drive local divers to do something about the Atlantic invaders.
In addition to trapping and hunting the lionfish to manage populations, researchers are also trapping lionfish in deeper waters, with the hope of studying them to decipher their invasive habits and gain insight into their behavior. For example, scientists can examine the contents of their stomachs to gain knowledge about their feeding patterns. Recent exploration of this has shown that, based on what they’ve been eating, lionfish are likely wreaking havoc in even deeper waters than expected. This is just the beginning of the research and it has potential to unlock many more questions.
“Ocean Invaders” explores creative methods for motivating locals to manage the lionfish population, as awareness of the issue builds. Incentivising fishing the invaders creates benefits that are twofold — businesses that revolve around invasive lionfish not only support the ecosystem, but local economies too. People are taking up lionfish hunting for side jobs, and it's even been gamified to create lionfish hunting tournaments.
Invasive lionfish are becoming an increasingly popular local dish, being introduced to cuisines across the Caribbean, Florida Keys, and Gulf Coast. From ceviche to fried whole, the fish can be used to create some island favorites, sustainably. People are even finding ways to use every part of the lionfish’s body — beyond just for eating. The film highlights how craftspeople repurpose the lionfish’s ornate fins to create jewelry, shoes, and other products.
As lionfish disrupt the balance of biodiversity along the Atlantic coast, it might be tempting to let nature run its course and see how natural selection pans out — but at what cost? We risk losing native species that play critical roles in their environments. When we disrupt ecosystems so rapidly, we dive headfirst into uncharted waters.
Watch On Your Schedule:
Premieres Wednesday, Oct. 26, 2022 at 9 p.m. ET/8C on PBS. The film will also be available for streaming online at pbs.org/nova, and via the PBS Video app.
Credits:
A NOVA production by Orange Frame Productions for GBH. Hosted and narrated by Danni Washington. Written, Produced, and Directed by Jeff Boedeker. Senior Producer for NOVA is Caitlin Saks. Executive Producers for NOVA are Julia Cort and Chris Schmidt. NOVA is a production of GBH.
