The effect of Halamid® in tropical marine fish farming is much less documented, even if similar disease problems occur.
Axcentive has therefore performed a test program to understand if the beneficial effects under tropical conditions are similar to those in cold water fish farming.
Particular attention has been given to the safety of the treatment to the high value fish concerned. Focus has been given on managing clean conditions in the land-based growing of fingerlings. After all, grow-out in tropical areas is still mostly done in flow through sea-cages, where microbial loading of the water is much less of an issue.
Three farm stages have been investigated: the hatching of eggs, the larvae rearing and the nursery.
Eggs
Fish eggs as received from own broodstock or external supplies can be a source of microbial contamination.
A simple egg wash in a Halamid® solution of 500–1000 ppm for 5–10 minutes showed 100 per cent effective in removing bacteria, including Vibrio. The hatchability of the eggs was not impaired by this treatment.
The optimal conditions depend on the specie treated, so please consult with Axcentive for further information.
Larvae
After hatching, larvae are grown for about 10 days before going to the nursery. This is a very sensitive life stage in view of microbial contamination. This was illustrated by the fact that in some of our tests the non-treated batch showed mass mortality.
The addition of Halamid® at only 2.5 – 5 ppm in the rearing media gave a full bacterial control (including Vibrio). This treatment was totally safe for the larvae.
Nursery
In the nursery, organic load in the rearing media starts to play a role with regard to the wellbeing (and thus the growth) of the fish. Also competition for feed starts being a factor of importance.
The addition of 20 ppm Halamid® every 6 days to the nursery tanks have shown a total bacteria and parasite control. Survival rates and/or weight of the fish have increased by 30–60 per cent.
In this stage, fish have to be in the best possible total health to survive and grow well and to the point of being able to survive the next grow out stage. If not, all efforts have been for nothing.
Conclusions
These tests have shown that even under the well-controlled conditions of a research facility, the output can be significantly increased by using Halamid®. The treatment with Halamid® is simple as long as the proper instructions are being followed.
Halamid® is effective yet safe for the different life stages.
This makes Halamid® different from various other products that are effective only at levels that also show toxicity to the fish.
Please do consult with Axcentive if you like to know more about the proper use for your fish and farm conditions. Always do a small test (‘bucket test’) before any first large scale use in your farm.
Further information can be obtained from local Halamid distributors or www.halamid.com.
