Back in the 1980s, when I became a certified diver, the handling of animals was viewed a bit differently than it seems to be nowadays. On those early trips I remember the Cheez Whiz cans, taunting an octopus or a turtle, and some other stuff Id rather not mention in the era of modern etiquette. Among these antics, making a puffer fish bloat was always an entertaining event.
I have some old slides of a divemaster in Saba presenting a puffed up puffer for my viewing pleasure. That shot was used in an advertisement. In fact, it was one of the first images I ever sold. In our sanctuary these days, youd get a severe reprimand from folks for that kind of behavior. I dont know if the puffers had post-puff trauma from those interactions, but it sure was enjoyable at the time.
Puffers are a group of species I like to shoot, especially the larger varieties. They have a shy, but jovial personality. At least they always look like they are smiling. Sometimes they wont turn around to face the camera, and sometimes they dont seem to care. They are not exactly speed demons of the reef, so a little patience and the right positioning as you gauge their path can provide good opportunities to take that perpetual grin home in your camera.
On the reefs in the Keys, I see mostly sharpnose puffers. Balloon fish are also common. Porcupinefish, which can grow as large as two feet in length, are also a familiar sight.
Puffers are related to boxfish, and are also toxic, but in a different way. I found many references to two toxins, tetrodotoxin (TTX) and saxitoxin (STX), which are nerve agents. They are chemically distinct, but act on the nervous system similarly.
And of course we have all heard the stories of death-by-sashimi in Japan if the dish is not prepared correctly. TTX is listed as the second most poisonous vertebrate toxin after the golden poison frog. While trunkfish are notorious for emitting their protective toxin, puffers keep it bottled up until they are opened.
I found an old article by a fellow in Indian River, Florida that called them tasty toadies. He used to eat them as a kid growing up around the water. As I poked around a bit more, I found an article that details toxic events and deaths from puffer fish from Indian River. Looks like somebody has a lot to be thankful for.
Based on what I found, its not the puffer itself, but the bacteria that it ingests thats the poison. These two toxins are sourced from bacteria. STX is attributed more to shellfish than fin fish, but both are found in puffers under the right conditions. Other fish eat the same bacteria, but dont accumulate the toxins. Also, water quality characteristics have a lot to do with the level of bacteria ingested by marine organisms.
TTX and STX cause paralysis by blocking sodium channels in a way that short circuits electrical impulses. Muscles cant contract, and when the toxin hits the diaphragm, breathing is halted. The TTX puffer toxin is thought to be a main ingredient in voodoo zombie powder.
TTX is a compound that is not fully understood. In a literature review of scientific works, Becky Williams of the University of New Mexico lays out a comprehensive look at this substance. In addition to the accumulation in puffer fish organs, TTX is vital to many other species, and has many functions. Beyond its toxic properties, it is also thought to be a sex trigger in puffer fish.
Some flatworms and the blue-ringed octopus use it as a venom. It is thought to be a natural repellant resident in eggs and larvae of sharpnose puffers. When a puffer puffs, it may also excrete TTX through its skin.
Apart from the literature survey, the most extensive work I came across on human intoxication was in the journal Marine Drugs, here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2525488/ There is also a good piece on incidents in the U.S. This paper points out that STX is also a major health concern. See http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626430/ for the lowdown on STX and its connection to TTX.
After reading that, I dont think Ill be ordering puffer fish anytime soon.
So for our local connoisseur, it was the characteristics of the water that kept his toadies tasty instead of making him toast. The toxicity levels in puffers elevated around 2004, prompting the ban on taking them. The ecological conditions changed, and what was previously present in nontoxic levels bumped up a notch to become dangerous. Until that time, there were very few reports of illness from puffers outside of the orient.
Now puffers are invading the Mediterranean, most likely coming through the Suez Canal. According to Discover Magazine, there are well over 700 invasive species in the Med now. And an article I read in the Daily Star of Lebanon cited destruction to fishing nets and the rise of puffers as a true menace to the region. In some ways it was almost a mirror image of the concerns we have from lionfish in the Atlantic. Eerie.
To me that brings up a natural curiosity about what else could be changing and if we will know before folks find out the hard way.
Tim Grollimund is a freelance photographer and PADI divemaster based in Key Largo. He can be reached at email@example.com or through his web site at www.timgimages.com. Tim is actively involved with the Coral Restoration Foundation and the Aquarius Foundation.