Science

20190816 Reef | Data

At 6:30 I was heading to the beach down SE 8th St. There were already divers in the waters and when I reached the reef I was surprised to see much more fauna and coral than at the structures of north and south. Still, no lionfish. 

We attended the derby kick off event, where Lad Atkins, the founder of REEF.org, reef environment educational foundation, spoke about the dangers of lionfish.

Pterois Origins

The lore around how lionfish were introduced into the Atlantic waters once pointed to Hurricane Andrew, which had smashed a large aquarium, situated on Biscayne Bay. Some of the fish which escaped were later retrieved,

Another theory was the lionfish escaped a Miami home aquarium that had been destroyed in the hurricane. Some believe they were simply released by aquarium owners who were distraught by the destruction of the aquarium life by a lionfish introduced by an unwitting individual. You can imagine it: a guy goes to a local aquarium store, sees this stunning fish, pays $80 for it, brings it home and drops it in his tank; an hour later all the other fish are gone. Then the guy thinks, shit, either I get rid of this thing or my aquarium is now just a glass cube with this fish inside. A couple weeks later we decide to release it into the bay. 

The observation of lionfish in waters around Florida as early as the 1970s suggests that it was not that singular event, at least not just Hurricane Andrew, but it could have been all of these contributing factors. What's interesting is that when the lionfish were first observed in  Florida reefs by marine biologists in the 1990s, they didn't remove them because they wanted to see if the species could coexist, that is, if the biodiversity of the reefs would improve with lionfish. And there are other non-native species that exist in Florida waters, which currently do not cause utter pandemonium. 

Another theory is that eggs or larvae were carried in ballast water from their native habitat and dumped in the ports of the US. 

A recent study showed that lionfish taken from the Gulf of Mexico and northeast Florida have homogeneous DNA, suggesting that a small group of ancestors as well as very little adaption as the population has spread.


Spread

With the average female spawning 27,000 eggs every three days, Pterois spp. have spread throughout the Caribbean, as far south as Brazil and colonized as far north as the Carolinas. As water temperatures change due to seasonal stream changes, populations can be found as far north as New York. They can inhabit water as shallow as a few inches and have been found as deep as 350 meters, over 1,000 feet.

Models of currents predict a future expansion of the lionfish domain, which can carry eggs and larva to distant places, such as the recent introductions to the Bahamas. At present the Bahamas have responded with their own derbies to try to forestall the population explosions of the invasive species. The colonization in the Bahamas confirms what the genetic analysis of populations of the east and west side of Florida suggest. But the prediction of ocean currents as a conveyance for Pterois is only one of the tools that bares bad news. The models of climate change, and increased water temperatures only makes matters worse. One study predicts, "the effects of warming temperature on lionfish pelagic larval duration and dispersal and predation rate, it was found that increased temperatures set the perfect stage for an invasion to thrive." Predictions expect a full 1-degree increase in water temperatures; with warmer waters, their range increases, but the larval stage is also shortened, permitting even faster rates of reproduction and growth. Waters at 10 degrees Celsius are lethal to Pterois spp. and feeding stops at 16 degrees C. With warmth spreading north and south, more species will be impacted permanently, and greater numbers of seasonal lionfish temporarily depleting native groups. 

In tandem with tools that predict further expansion are unexpected spread of lionfish. As the problem has garnered more interest and concern, increased monitoring and research has found lionfish adapting to deeper depth, and cooler waters, than previously believed. Individual lionfish have been found at reefs as low as 1,000 feet deep. It’s not clear if this is an evolutionary adaptation or simply a trait that was not recognized.

The spread of lionfish is also occurring in distant, unconnected locations. In 2012, colonies of lionfish began to appear around Cyprus, Greece, Turkey, Tunisia. In the cooler waters of the Mediterranean, procreation is not expected to occur at the same rate as at the equator. Rather, their presence is a bioindicator of the nodes of globalized trade.

Not only do these derbies have a direct impact on the coral reefs, they are also used to gather data on the life and biology of lionfish. When each teams’ fish are counted, they are also measured in order to get a sense of the age of the population. The fish are put on ice if they will be eaten as part of the event, sold for consumption, or further analyzed. Researchers have used these catches as opportunities to examine the stomach contents of lionfish, which form statistical analyses that would be otherwise prohibitively expensive for research teams to conduct. From these studies, researchers have shown the dramatic breadth of what lionfish may eat, as well as the unexpected capacity of their appetite. Collectively, these analyses are the foundation of the hysteria around the lionfish invasion, but they also demonstrate a relationship between humans and marine life, a relationship that is quantified and driven by data. This may not seem remarkable unless its juxtaposed with how we thought of marine life a half century ago. Popular knowledge would be informed by television shows like Flipper (1964-1967) or The Undersea World of Jacques Cousteau (1967-1976), also scientific understanding was informed by the technologies built that Cousteau developed, such as the Conshelf 1, the underwater habitat for humans. Even within a decade from the airing of Sea Hunt (1958-1961), which was essentially an underwater police show, and Cousteau, the focus has shifted from people underwater to the lifeforms found underwater. While Sea Hunt may continue the military origins of the SCUBA equipment, Cousteau continues the ontological pursuit of Melville’s Moby Dick. While Melville’s 1851 classic follows the unknown movement of a singular white whale, we can only imagine how the book would read in today’s context in which marine life is tagged and tracked with technologies that extrapolate the lifeforms’ relationship to the ocean and how we may mitigate our impact on those species. 

I was surprised by some of the data shared at the kick off event: some reefs lost as much as 95% of marine life; on average a reef loses 45% when lionfish are introduced. While I was surprised and appalled, the rest of the audience had mostly heard the presentation, which I took as a bad sign, since that equated to their experience. The only rise from the audience came when Lad solicited remarks on what it was like to be stung by a lionfish. One man shouted out that he cried like a baby, as if he were confessing his trespasses. We met a team that had won 11 tournaments and included the inventor of the Zookeeper, the standard container to hold lionfish. I spoke with a PhD candidate who had been researching the human influences on environmental systems. One thing that was clear: we were in over our heads.