Hi guys, welcome back to Tidal Gardens. When it comes to reproductive methods, corals
have a diverse skill set. They are capable of sexual reproduction as
well as a variety of asexual methods such as longitudinal fission seen in corals like
Caulastrea, budding as seen in corals like frogspawn, or pedal laceration seen in mushrooms,
and especially fragmentation which makes companies like Tidal Gardens possible. There is however a much less common method
which is the subject of this video. Polyp. Bailout. Ok, roll that intro! Before we delve deeper into this topic please
take a quick moment to subscribe to this channel if you are into informational videos on corals
and reef aquariums in general. Subscribing helps this community grow and
it is a good way to stay notified whenever we upload new content. Polyp bailout is a stress response to unfavorable
tank conditions that certain stony corals can activate as a last ditch effort to save
themselves. You may have seen corals express stress reactions
in other forms. For example, regulating zooxanthellae can
be seen whether it is “browning out” to increase the population or “bleaching”
which is essentially expelling zooxanthellae. Some corals prefer low light and as a stress
response to too much light might form oxide radicals in their bodies that resemble bounce
mushroom bubbles. It is part of the reason why the first time
I saw a bounce mushroom the first thing I thought was it was just a regular Rhodactis
with horrible tumors. Anyway, those are just some examples of stress
reactions that are fairly common. Polyp Bailout is a much more extreme measure
which I liken it to a fighter pilot hitting the eject seat and hoping for the best. During Polyp Bailout, Polyps are killing off
their own connective tissue through apoptosis. For those that are unfamiliar with the term,
apoptosis is programmed cell death as opposed to necrosis which is traumatic cell death. Apoptosis is a highly regulated and controlled
process so the coral polyps bailing out due to stress are doing so in a direct calculated
response to an exogenous threat. It is certainly not a common occurrence but
over the years I’ve seen it happen in SPS like Pocillopora, and Stylophora as well as
LPS such as Euphyllia and Catalaphyllia. The SPS corals seem to do this much more successfully,
but perhaps it is just a numbers game. A colony of Pocillopora or Stylophora might
expel a hundred polyps during a polyp bailout event where only a small fraction survive
and regrow on a more favorable substrate. This is in contrast to a large polyp stony
coral like an elegance where it is just a single polyp with a sliver of a chance of
survival after bailing out. When things go right however, it is an unexpected
surprise. We tend to see SPS colonies pop up seemingly
out of nowhere on the side glass of the aquarium or an overflow box. Although much less common, here is a head
of Frogspawn that detached in horrific fashion to regrow on the bottom of the tank. This little head has survived now over 6 weeks
so I think it is well on its way to recovery. So what causes a coral to decide to bail out? That is not so clear, but there are a number
of possibilities. First off is any shift in temperature. In a home aquarium temperatures are relatively
stable as compared to my greenhouse for example, BUT when something goes wrong in a home aquarium
temperature-wise the effect is way more severe. Small water volumes can either heat up or
cool down very quickly and that could cause this type of stress response in coral. Similarly, sharp changes in salinity could
be the cause. Again, it is not typical for an aquarium to
go crazy salinity-wise, but it could happen especially when the testing device has not
been calibrated in a while and the readings might have drifted significantly. I’ve seen a refractometer be off by a whole
.005 so a reading of 1.025 was ACTUALLY 1.030. On top of that, there were plenty of times
where that tank was giving readings of 1.028 or 29 meaning the specific gravity of that
tank may have drifted towards 1.035 which is WAY too high. Having said that, the animals in the aquarium
may have a muted stress response to that salinity because that sort of change happens gradually
BUT the moment you get that new coral, that poor little sucker is going to be in a world
of stress. Even if you took an insanely long time to
acclimate it, there is a really big difference between acclimating a coral for an hour and
slowly changing salinity over a few months. So THAT could be a stress inducing event that
could activate polyp bailout. Three… there could be a chemical change
in the aquarium which could be either too little nutrient or too much nutrient. I’ve seen one scientific journal describe
polyp bailout happening to a specimen with low food availability and I’ve personally
seen it happen in systems with an overabundance of nutrient and high nitrate. Lastly, I could see corals bail out due to
some manner of pest infestation or harassment from a fellow tank inhabitant like a fish
or invert. Ok, that does it for this short overview of
polyp bailout. I hope you never have to experience it happen
in your aquarium, but it is something to be aware of none the less. This hobby isn’t always puppy dogs and rainbows
and occasionally our tank lets us know when we are being unfit coral parents. Anyway, I hope you enjoyed the video. As always, don’t forget to like, comment,
and subscribe and until next time, happy reefing.