Theory on velvet

[Humblefish]

If velvet photosynthesizes and chlorophyll has a distinct fluorescence to other materials(animal proteins, rock etc.) could uv light be used as a diagnostic tool? Is the trophont fluorescent or just the dinospores? Is there enough glow of the dinospores to see against the reef? To follow the progression of a fallow period. If the trophonts have a distinctive glow compared to ich could uv be used to diagnose one vs the other?
Had read a paper on uv diagnostic of human scabies a little while ago so this came together for these questions.

Velvet dinospores are less than 10 micrometers in diameter and invisible to the human eye without the aid of a microscope.

 

[Lowell Lemon]

So if light is the possible link how come fish in the ocean display very little disease? The par of natural sunlight far exceeds many reef tanks.

 

[EmdeReef]

I’ve been discussing something similar with a friend at AIMS and in his view there is no significant increase in diseases in Australia, but again the data integrity is very poor.

I wonder if this could be traced to the consolidation of wholesalers and even fish stores in NA?

It’s also possible that the LEDs have impacted specific pigments of the a.ocellatum.

The reason I remain a bit of a skeptic on the actual strength of light is that over the course of dinoflagellates history the sun has oscillated quite a bit. In evolutionary terms that would likely mean much quicker adaptation for survival and in more recent times that would mean an adaptation to dimmer lighting conditions. From that I wouldn’t think that 10-20yrs of stronger artificial lights would make a meaningful impact.

However, the specific wavelengths change would throw the above argument to garbage. There are enough studies about soil parasites response to different light wavelengths to make your theory plausible... in sum, I don’t know but it would sure make an interesting research study!

 

[Humblefish]

So if light is the possible link how come fish in the ocean display very little disease? The par of natural sunlight far exceeds many reef tanks.

Maybe velvet dinospores are attracted to natural sunlight, propel upwards towards it, and fish know to stay away from the surface of the water? Good way to avoid getting caught as well. In our tanks, fish usually come to the top of the water in anticipation of food.

We know velvet exists in the ocean and probably takes weak/injured/older fish down, but the number of free swimmers is so diluted that a healthy fish's natural immune system should be able to fend such a low concentration off. Different ballgame in a glass box with a closed system. Without the benefit of QT, you'd need to run a UV sterilizer or diatom filter to mimic the ocean's "low concentration" parasite norm and of course, boost the fish's immune system via proper nutrition. Sometimes that strategy works, sometimes it doesn't...

 

[EmdeReef]

Maybe velvet dinospores are attracted to natural sunlight, propel upwards towards it, and fish know to stay away from the surface of the water? Good way to avoid being caught as well.

We know velvet exists in the ocean and probably takes weak/injured/older fish down, but the number of free swimmers is so diluted that a healthy fish's natural immune system should be able to fend such a low concentration off. Different ballgame in a glass box with a closed system. Without the benefit of QT, you'd need to run a UV sterilizer or diatom filter to mimic the ocean's "low concentration" parasite norm and of course, boost the fish's immune system via proper nutrition. Sometimes that strategy works, sometimes it doesn't...

^^ agree and also let’s not forget that in the ocean velvet would have predators. What would be interesting to find out if over the last 100+ yrs the predators have been in decline...

 

[Lowell Lemon]

There was a video posted here on R2R about virus and bacterial concentrations measured at various reefs around the world. One interesting aside was the meaurement of an atol where the coral, clams, and other filter feeders in high concentration in the middle of the atol seemed to filter most of the virus and bacteria by the time it exited the other end (kind of a one way flow natural through). I forgot who the lecturer was but it made me take notice.

I think U.V. and diatom filters are beneficial in this regard. Some of my best success used mechanical and U.V. in both large and small displays.

 

[Humblefish]

Speaking of bacteria, Dr. Angelo Colorni once theorized that bacteria “gnaw” on tomonts and eventually damage them. Obviously there are greater numbers of bacteria in & around coral reefs than inside our little fish tanks, so perhaps this also explains why ich, velvet, etc. doesn't seem so rampant/deadly in the wild. By using bacteria, Mother Nature keeps those little jerks in check.

 

[Gareth elliott]

This is only slightly related but they just finished a genomic study of Ichthyophthirius multifiliis and discovered two symbiotic bacteria species within it. Are doing tests now if fw ich requires them for survival.

 

[Reefer33]

This theory might also lead to why we also see more and more dinoflagellates outbreaks cropping up in tanks. I've been in the hobby awhile myself, sure you would see the occasional cyano or hair algae outbreak, but not until recently have seen all these tanks being broken down due to not being able to take care of dinoflagellates. Correlation doesn't make for causation but LEDs sure became prevalent on the scene about the same time. Could it also be due to nutrient starved tanks that everybody runs now a days? That's the other "trend" that seems to correspond.