Bioremediation - Can brine shrimp stop Velvet?

[robert]

In the confines of our tanks - when we get blooms of undesirable organisms we often employ another organism to get things back under control - the use of a harlequin shrimp to eat asterina startfish, or a copper banded butterfly to take out aptasia are a couple of examples. These can be great solutions when they work.

I thought it would be interesting to hear what fellow reefers have employed along these lines - what was the pest - what was the control - and how did it turn out?

Here's one I ran across that I've never heard of before that's got my interest...Using baby brine shrimp to control or eliminate marine velvet...Practical? maybe, maybe not, but a very cool idea. What do you all think?

The potential for using nauplii of brine shrimp Artemia salina to remove the dinoflagellate Amyloodinium ocellatum from aquaculture systems for red drum Sciaenops ocellatus was investigated. Dinospores of A. ocellatum were dispensed in cell culture plates at a concentration of approximately 10,000/mL and were exposed to brine shrimp nauplii at concentrations of l, 2, 4, or 8 nauplii/mL over a 24‐h period. 1n the presence of 8 nauplii/mL, dinospores were eliminated in 8 h. In another study, 300,000 dinospores were placed in 3 L of saltwater in two tanks, and l,000 nauplii were added to one tank. After 12 h, three 202‐g red drums were placed in both tanks for an additional 12‐h‐exposure period, after which the fish were euthanized and the trophont load on gill filaments was assessed. Fish from the tank with brine shrimp nauplii had 65% fewer trophonts on their gills than those from the nontreated tank (10.75 versus 3.75 trophonts/filament). These data and the observation that dinospore remains could be observed in naupliar fecal casts suggest the potential value of brine shrimp as a bioremediation measure for this serious gill parasite.​

https://afspubs.onlinelibrary.wiley.com/doi/pdf/10.1577/1548-8667(1995)007<0257:CCOAOD>2.3.CO;2

https://afspubs.onlinelibrary.wiley.com/doi/epdf/10.1577/1548-8667(1995)007<0257:CCOAOD>2.3.CO;2?purchase_referrer=scholar.google.com&tracking_action=preview_click&r3_referer=wol&show_checkout=1

 

[Instigate]

How interesting! Thanks for sharing.

 

[Instigate]

@Paul B

 

[robert]

Alright...so how about this. When or slightly before adding any new stock add decapsulated brine shrimp eggs to the display...In our tanks the brine shrimp typically don't have a sufficient food source - so any velvet would be their food source. It looks from the study that one nauplii consumes 300 dinospores.

They then become food for corals etc...

 

[robert]

Just ordered a pound of eggs to give it a try...what can it hurt? Don't have velvet, but we'll see how they fare in the tank...if nothing else - coral food...

 

[KrisReef]

This might change the Quarantine Rx method for treating marine velvet?
Probably not practical in a circulating DT, or with a skimmer.

 

[robert]

It at least is something that can be done in the DT. Even if it only slows progression and spread enough to get a hospital tank etc set-up...

 

[robert]

Well those brine shrimp eggs are non-hatching - but my gonis seem to love em - so coral food...
I've ordered hatching decapsulated brine shrimp eggs and will add those when they get here - probably just more expensive coral food....

FWIW - turns out that peppermint shrimp can and do eat the encysted stage of cryptocaryon irritans...(ich)...both might be useful additions -

Makes me curious if pods in general don't consume these (and other ciliates in general)...might explain why so many with mature tanks get away with ich management...

Something to read: https://www.int-res.com/abstracts/aei/v10/p429-436/

 

[robert]

So in the link provided you'll find a link to the full study... but the relevant part in summary...

"In our recent laboratory trials (Vaughan et al. 2018), L. vittata was effective at reducing and consuming the benthic stages of the cilio phoran ectoparasite Cryptocaryon irritans Brown, 1951, and the cocoons of the marine leech Zey lani cobdella arugamensis de Silva, 1963."

 

[Paul B]

@Paul B

What!

 

[Instigate]

What!

Thought you might find that article interesting! You used to or maybe still do BBS daily right?

 

[Paul B]

I did, but find it relatively useless in our tanks.

 

[VR28man]

I did, but find it relatively useless in our tanks.

That’s interesting. What made you change your mind?

 

[Paul B]

It was never my mind to add baby brine shrimp to kill velvet or anything else. I use the shrimp to feed pipefish and mandarins. The small amount of parasites they "may" eliminate IMO would make no difference in disease control

 

[Scott Campbell]

It was never my mind to add baby brine shrimp to kill velvet or anything else. I use the shrimp to feed pipefish and mandarins. The small amount of parasites they "may" eliminate IMO would make no difference in disease control

But it is likely that not just baby brine shrimp and peppermint shrimp would knock back parasite populations. I expect lots and lots of things in a mature tank (sponges, copepods, amphipods, worms, mysis shrimp, corals, etc.) would work to suppress disease by consuming parasites. I still believe a "disease resistant" tank is more a function of bio-diversity and tank maturity than individual fish building up immunity by exposing them to life-threatening diseases. Just my two cents.

 

[Paul B]

OK, But I think it's still immunity. It doesn't matter as long as it works.

 

[Gareth elliott]

How many would you have to add to make a meaningful dent in populations? As a comparison a single brown bat eats 1000 mosquitoes a night there are on average 9000 bats in a colony, so 9,000,000 mosquitoes a night are eaten. On a summer night i still get my tushy eaten off in my backyard while watching the bats fly over my head.

 

[Cory]

Im curious if brine shrimp would eat dinoflagellets

 

[AlexG]

I think this is an interesting topic. While this was related to brine shrimp I do wonder what role that micro/macro fauna living in our reef tanks play in the control of parasites during stages that settle in the substrate or are free swimming. Every time I examine sand samples from my tanks under a microscope it is crawling with life which must be consuming food to survive. It would be interesting to run controlled experiments using different species of copepods, amphipods, ostracods, worms, ect... to determine if they will consume free swimming or parasites settled in the substrate. I believe that healthy fish with a strong immune system is very important to ensuring that parasites stay in check but as a reef ecosystem is so diverse with life though it would be interesting to learn if there are other food webs that help keep parasites in check.

 

[robert]

"How many would you have to add to make a meaningful dent in populations? As a comparison a single brown bat eats 1000 mosquitoes a night there are on average 9000 bats in a colony, so 9,000,000 mosquitoes a night are eaten. On a summer night i still get my tushy eaten off in my backyard while watching the bats fly over my head."

I like this analogy! A mosquito has a multistage life-cycle with a female laying a clutch of between 100-500 eggs a week or two apart. This is similar in a gross way to ich's life-cycle as far as reproductive rate. The number of tomites which develop inside a ich tomont falls in a similar range on a similar timescale so population growth dynamics might be similar.

Absent predation, if you started with just 100 female mosquitoes and every two weeks they lay 500 egg, after just six weeks you'd have 12.5 billion mosquitoes and 2 weeks later 6,250,000,000,000. 6.25 trillion mosquitoes.

So despite predation by bats you still get bitten. Does the mean the bio-remediation provided by bats against mosquito's has failed? If you were caged on an island in a swamp with those 100 females in an environment without predation, you probably wouldn't make it to the six week mark and if you did I'm sure you'd wish you hadn't.
That's a very good analogy to how ich behaves in a brand new tank.

Burgess, Brown, Lawler and others ran the studies on which we base most of our understanding and practices when it comes to these two parasites in particular.
They did so in lab environments not reef tanks, so while we can and do learn a lot from them, some of their data and metrics don't necessarily translate directly and can be somewhat misleading when thinking about our tanks.

For example - when they exposed fish to ich, they did so in a very confined space with swarms of theronts to ensure maximum contact time between theronts and the host fish, but even in doing so they discovered that it was more likely than not that most of theronts didn't find a host. In fact only between 5 and 20 percent found and successfully attached to a host fish even in the best possible lab created situations.

On the reef, theronts get swept off to deep water, sink through thermoclines, get eaten etc. Tomonts (which we assumed were virtually impervious) and theronts are obviously food for other benthic organisms as demonstrated in the studies above. A tomont eaten by a peppermint eliminates hundreds of potential theronts and a brine shrimp hatchling can consume upwards of 1200 dinospheres in 8 hours. That's not a small predation rate, and has a profound impact on ich's future population growth, increasing the number of cycles before lethal densities are achieved in the tank.

Here is where the the mosquito analogy breaks down a bit as fish develop immunity to ich whereas we don't necessarily develop immunity to mosquitoes. A fishes immunity to ich takes time to develop and that's where even imperfect predation can have the effect of extending the time before parasites reach the numbers sufficient to overwhelm the host. This extended time coupled with the fishes developing immunity turns the tide and hold ich's population in check at sub-lethal levels and further since an immune fish doesn't play host to ich - breaks the back of the bloom and collapses the ich population.

It is ultimately immunity which makes this work - but immunity waxes and wanes - it is also a mature tank with a matrix of ciliate predators, sufficient dilution through good filtration and flow which makes mature tanks resistant to sudden blooms sufficient to prove lethal to its residents as it is the sudden bloom that kills.

Its a myth that you have to eliminate ich and velvet from your systems or all you fish will suffer and die and its based on misapplication of the data from very good studies. What this leads to is to cumbersome husbandry practices, sub-optimal treatment of fish and frustration on the part of hobbyists.

We have adopted the practice of seeding tanks with bacteria as part of the cycle. Could we not do the same for the benthic predators of some of our most commonly encountered ciliate parasites? I don't think its far fetched. Thank god for bats!