Sunday, March 30, 2014

Lionfish: The Unwelcomed Guest

Lionfish by Corbis
Everybody knows someone whom they don’t particularly enjoy being around. In the marine world, specifically the eastern coast of the U.S., this unwelcomed guest is the Lionfish. You may ask what does this fish do to make everyone hate them? Well for starters, this alien fish is highly toxic and likes to kill smaller fish and invertebrates. They are starting to become a major problem in the eastern U.S. because they are indigenous to the Indo-Pacific region and have few predators here. Therefore, nothing is keeping their numbers under control (besides humans). Allow me to explain their toxicity. The Lionfish has spines that it uses to sting its prey. When it strikes its prey, acetylcholine and a neuromuscular toxin are released. This can cause tremendous pain, respiratory distress, and even paralysis. (Lionfish Biology Factsheet). Because of these things, their invasion has led them to be considered one of the world’s greatest conservation issues (sort of a “Most Wanted” list). Basically these are some bad dudes!

The research article, “Invasive Lionfish Drive Atlantic Coral Reef Fish Decline”, gives a great insight into what effects the Lionfish are having on the indigenous fish in the Atlantic and Caribbean. There are numerous invasive species found throughout the U.S., but the article tells us that the Lionfish invasion is of “unparalleled speed and magnitude” (Green). In other words, we aren’t dealing with your average, run-of-the-mill, invasive species. In fact, the research done by Green et al., which was performed off of New Providence Island, Bahamas. Results from nine different coral reefs showed that “40% of the total predator biomass” was comprised of the Lionfish. That is a tremendous amount when you think about what percent this should be (zero: they shouldn't live there). Perhaps an even more shocking statistic is that in just two years there was a “65% decline in the biomass” of the 42 fish species in the Atlantic that fall victim to the lionfish. Whats more, the Lionfish were present in the Atlantic prior to 2008 when the latter report was performed. Therefore it is fair to assume that the total decline is greater than just 65%.

The graph above gives a good depiction of the native fish species biomass between 2008 and 2010. As you can see, the small-bodied prey had about 65% decline in biomass as mentioned, and the large-bodied competitors and non-competitors alike had a decline. Only the small-bodied non-prey species have benefited from the lionfish. This is probably because of less competition with other small-bodied fish and less predation by the large-bodied fish.

It appears that the lionfish is causing an underwater apocalypse and by this point your probably asking yourself if this is any hope? Well to be quite frank with you, we don’t know but its not looking good. The research article warns that the fish will have the same impact elsewhere in the Atlantic when it reaches the more northern waters. Additionally, when small-bodied prey become scarce they could go after the young from the large-bodied fish. All of these species of fish have their own niche and duty in the ocean and such a drastic reduction in biomass could be truly detrimental to the ocean. This is especially true when over-fishing, disease, toxins and other threats are impacting these species as well. Green et al. states that “given the geographic extent of the invasion, complete eradication of Lionfish from the Atlantic appears unlikely”, but it could be possible to keep them out of important nursery sites and protected areas. Some regions are actually giving prizes and money to people to catch these bad guys.

The fate of the oceans and lionfish is still yet to be determined, but with any luck their numbers will be controlled. For if not, their impact will be tremendous.
I told you these are some bad dudes. The picture above shows the wound from a Lionfish. The pressure builds up so greatly in the wounded area that typically the skin must be sliced open and  drained. As the picture shows.

Corbis. Unknown in the Amercias 30 years ago, lionfish have multiplied at a rate that is almost unheard of in marine history. Picture. Visuals Unlimited.

Green, Stephanie J., John L. Akins, Aleksandra Malijkovic and Isabelle M. Cote. “Invasive Lionfish Drive Atlantic Coral Reef Fish Declines.” PLoSOne 10.1371 (2012):Web.

Lionfish Biology Fact Sheet. NOAA, 31 May 2011. Web. 30 march 2014.


  1. Loved your post Scott! So how are the lionfish invading the Atlantic Ocean if they are from the Indo-Pacific? Are their larvae getting into the water? Or are people releasing them after having them as a pet?

  2. Great question, they are believed to have entered during Hurricane Andrew. There was an aquarium in Southern Florida that had Lionfish in it and they got loose from the storm. They aren't positive about this, but multiple sources attributed their release to this event