The Oyster Toadfish’s journey into orbit
I absolutely adore “ugly” fish. I’ll pass on the betas, the designer goldfishes, and the flashy tropical varieties. Give me a fish that looks like a Jabba the Hutt love child. The Oyster Toadfish is one such fish, and its mother certainly was not Princess Leia.
I worked with these beauts during one fortunate summer and the best way I can describe them is ‘The Oscar the Grouch of Fish.’ For one, the Oyster Toadfish resembles the irritable Muppet; their football-shaped heads are consumed by scowling mouths so wide one would half expect them to be operated by a puppeteer. Just above their pouty lips protrudes wonky eyes which tend to look crossed when viewed head on. I for one think it engenders a lovable nature to these little guys much like Oscar’s unkempt unibrow. Framing this masterpiece of a face are little barbels—whiskers—that oddly enough look like the result of say, living in a trash can. Funnily enough, that is just what Oyster Toadfish love to do.
Rather uniquely, these slimy fish seem to be unfazed by polluted water. Indeed, they almost prefer the natural hiding spots that man made debris allows (at my job, they loved to lounge in PVC pipes and cement blocks). They have even been observed gathering up garbage to transform into cave-like breeding shelters.
So how did this ugly toad turn into NASA’s prince, hitching a ride into the great unknown? Well it had a few so-called ‘fairy godmothers.’
John Glenn was once such fairy godmother, or rather godfather. He was the first American to orbit the earth in 1962 and nearly 40 years later, at the age of 77, returned to space as a guinea pig to study the effects of microgravity (the weightlessness we associate with the absence of gravity). The resulting STS-95 mission was concerned primarily with this meta-research: trying to understand the effects space travel has on astronauts.
The second fairy godfather is Stephen M. Highstein, a researcher at the Marine Biology Lab (MBL) in Woods Hole, MA. Highstein was interested in the vestibule system (sensory system primarily controlling balance) and found a good lab rat in the Oyster Toadfish. Humans are able to land a triple axel or simply walk to the mail box because there are calcium carbonate crystals in our ears. When we move our head to the left the crystals shift. Our brains take in this information and piece it together with the visual informational coming from our eyes; together these inputs prevent us from falling over every time we move. Motion sickness, for example, can be thought of as a miscommunication between our ears and our eyes. On a boat our ear crystals shift because the boat moves, however we do not perceive our surroundings as moving because they move along with the boat. The resulting mixed information leads to the all too familiar uneasiness. A very similar phenomenon occurs to astronaut as the microgravity disturbs the crystals, known as otoliths.
So what do Oyster Toadfish have to do with any of this? Well, like us they also have ear crystals. In fish, otoliths are these tiny white plates that have rings much like a tree’s rings that are generally thought to correlate with the fish’s age. In fact we use the rings on these crystals to understand fishing populations (this however, is a story for another day). Highstein used Oyster Toadfish in his vestibule system research as their otoliths were easy to find in a dissection and quite large due to the fish’s Muppet head. The loud, fog horn and almost cicada-like mating noises in addition to their habitat just under dock pilings outside Highstein’s office at the MBL made these fish particularly accessible and hence even better test subjects.
In place of a princess kiss, NASA plucked the toads from their garbage enclosed hiding places and suited them up for space. After 9 days in orbit, the two Oyster Toadfish successfully returned to Earth and eventually to Woods Hole for further testing. Honestly, the results were…lackluster. For starters, the sample size was probably too small to draw meaningful conclusions. There were four, of which only two survived, aboard the STS-90 (which ran a similar experiment) adding to the total of 4 in the experimental group. Furthermore, I personally have unresolved qualms about the comparison to the control group. Fish are notoriously easily stressed. The oyster fish I worked with would get extremely upset if I took their PVC pipes out for cleaning. So I imagine that the takeoff and landing of Discovery could have been a confounding variable (as the control group was simply physically moved in their tanks). Regardless, experimenters found that the fish had a similar experience with space adaption syndrome (aka motion sickness in space) as humans did with there being a greater acclamation time when leaving Earth than returning to it. One research article also hypothesized that, “we would not expect significant remodeling of the spatial extent of dendritic arbors of afferents within the sensory epithelium to have occurred” (Boyle et al.). I was also hopelessly lost at each word of this sentence until I got a dictionary in front of me. What I believe they are saying is that this process did not make any new synaptic connections. In other words, it is unlikely that exposing astronauts to microgravity beforehand would help their transition, it just seems to be an inevitable part of the journey.
Was this experiment a total bust? Of course not! No experiment really is, there are always things to be learned even if those things just reaffirm what we already expected. Additionally, simply sending fish into space leads to better engineering and experimental design for the test animals. (I would also be remiss if I did not direct you to one research paper that has a delightful illustration of the Oyster Toadfish).
I love this little tidbit about the Oyster Toadfish as it is a real underdog story. Fisherman never want to catch them because of their less than ideal features. Their propensity to bite anything that floats in their crossed line of sigh, say a Fisherman’s boot, has also earned them the rather unfortunate nickname, “The Mother-in-Law Fish.” Yet, we as humans and scientists still have a lot to learn from them, as we do all creatures. I think that is pretty beautiful.
If you are interested in the vestibule system especially how it operates in space you can check out this demonstration by an astronaut aboard the ISS.
If you want to hear the lovely Toadfish fog horn croak, you can visit the Ocean Conservatory Research website.
Lastly, if you also think the Oyster Toadfish is a handsome little guy you might want to check out some of the goods at toadfishoutfitters.com as proceeds go towards planting oyster beds to increase coastal water quality and combat toxic runoff. I am not associated in any way with this website, I just stumbled across them in my researching.
Boyle, Richard, et al. Neural Readaptation to Earth’s Gravity Following Return From Space. Journal of Neurophysiology. 1 Oct 2001.
Marine Biological Laboratory. NASA Studies Balance In Two Woods Hole Toadfish, A Senator, And Five Astronauts In Shuttle Mission. ScienceDaily. 2 November 1998. http://www.sciencedaily.com
NASA. Mission Archives. NASA. http://www.nasa.gov
NOAA. What causes seasickness? National Ocean Service website, oceanservice.noaa.gov
Sakimura, Toru, et al. NASDA Aquatic Animal Experiment Facilities for Space Shuttle. Biological Sciences in Space, Vol. 13, No.4 1999.
Deeper than the Sea 