can long term hypo be harmful?

[jmaneyapanda]

In a discussion with some fellow reefers regarding the pros and cons of hyposalinity, I have run into a wall. I am a firm believer in treatring only when necessary, and not routinely or prophylactically treating fish (as to minimize unnecesary stress). Some opponenets of my view have asked for evidence that such hyposaline exposure cause ANY negative effects- and I am honestly unable to find much, except for personal accounts. What do you guys think? Is there any literature or studies?

 

[TerryB]

I have seen plenty of scientific studies reported in the journals indicating that at least some marine teleost fish actually grow faster in salinities (not SG) ranging from 12 to 14ppt. Lots of benefits to hypo. Haven't seen anything to back the idea of kidney damage in marine teleost reef fish.

Terry B

 

[jmaneyapanda]

Terry- thanks for the response. Most of the information I canm find are quite anecdotal and imprecise. For example that claim many teleosts can "adapt" or "withstand" the hyposalinity, but do not define this, nor have any time scale aside from vague "up to 4 weeks", etc. Do you have any refeneces I can find which are a bit definitive and scientific? As I said, everything I am finding is just heresay, anecdotal, or non-empirical. Thanks.

 

[TerryB]

Carneiro, P.C.F. & Urbinati, E.C. "Salt as a Stress Response Mitigator of Matrinxa, Brycon cephalus (Gunther) ,During Transport." Aquaculture Research, 32, 297-304, 2001.

Lim, L.C. Wong, C.C. Koh, C.H. Dhert, P. & Sorgeloos, P. "A Stress Resistance Test For Quality Evaluation of Guppy (Poecilia reticulata)." Abstract Book of First AVA Technical Seminar, pp. 4-5, Agri-food & Veterinary Authority of Singapore, Singapore, 1 September 2000.

Wedemeyer, G.A. "Handling and Transportation of Salmoniods," Principals of Salmoniod Aquaculture. Pennel, W. & Barton, B., eds., Elsevier Publishing, Netherlands, 1996.

Lambert, Y. Dutil, J-D & Munro, J. "Effects of intermediate and low salinity conditions on growth rate and food conversion of Atlantic cod (Gadus morhua)."
Canadian Journal of Fisheries and Aquatic Sciences [CAN. J. FISH. AQUAT. SCI.]. Vol. 51, no. 7, pp. 1569-1576. 1994.

I can find more references if you need them, but this should give you a good start on the benefits of hyposalinity.

Terry B