Question for Brett

[B.Scott]

Brett,

I was reading an article about salt in the forum of a Dutch vet. He states several things that seem to me to be completely out of wack.

First he states
"There are several type of parasites unaffected by salt, like trichodina. Other parasites like costia actually thrive and treble their reproductive rate in a saline environment".

Now before I run off and embarrass myself, do you as a biologist know of any info that supports this? I'm been searching but have yet to find anything that supports or disputes his claims.
We all know that in the past, before many strains built up a resistance, salt was a common treatment for costia infection
Still it would seem to me that it is unlikely that despite resistance to salt, costia would actually be stimulated in the presents of salt.

My first inclination is simply to ask the guy to back up his facts. In the meantime any extra backup is welcome.
B.Scott

[JasonS]

JR and this vet must read some of the same books. Here's a quote from JR regarding costia and salt from this thread. (Post #5 is most instructive)

"And forget salt, Ichthyobodo is found on salmon in 34% seawater! Only if you are lucky enough to have a wimpy local freshwater species will salt work. The idea that these protozoa are gaining resistance to salt, by the way , is incorrect and naiive." (exact quote)

I'm inclined to agree with the vet; trich and costia aren't cured by salt alone. Costia can be zapped by salt plus high heat, maybe, while trich is dealt with by PP at relatively low rates as a preferred treatment.

[B.Scott]

I agree about using salt as a cure... useless. But does saline increase reproduction rates?

[JasonS]

That's probably specific to a type that can live in both fresh and salt water. It probably does better in saltwater.

Increasing salt from .1% to .6% shouldn't make a diff.

[Fishbreeder]

I been on sabatical, I wish. Box got struck by lightening. That weren't so bad, what was bad, so was my primary water supply at the koi farm...ouch. Backup box here at home and new pump in the big water well at the farm now.

I live and work as a biologist and fish farmer in the estuary. Most of the local flora and fauna, inluding parasitic ones are tolerant of a wide range of salinities.

More specifically I agree that salt has little or no effect on Trich or Costia. It is very conceivable to me that a particular species or strain of parasite might trhive better at one salinity than at another, and increasing ambient salinity might cause it to increase, rather than decrease, in numbers.

I'm also of the opinion that it wasn't truly the development of salt resitant strains trhough salt use that rendered salt a less effective tool in some cases. Rather it was the spread of already tolerant strains of parasites from estuarine locations that brought thjis about. Alternatively it never has been the case and only a bunch of anecdotal information.

Brett