Diseases can have significant economic impact on aquaculture operations. For example global economic loss due to white spot disease, a viral disease of prawns, was estimated to be $US3000 million/year in 2001 (Hill, 2001).
Disease is a departure from the normal health status of the animal. In aquaculture disease can cause decreased weight gain, poor feed conversion ratios, unmarketable product and in more severe disease, some or all of the animals in a population may die.
Aquaculture diseases can be caused by:
A. Non-infectious causes
- Nutritional factors such as poor or imbalanced diet, too much or too little food and unpalatable food
- Cancer
- Gas bubble disease
- Physical damage e.g. sunburn, electric shock, cannibalism
- Toxins e.g. pesticides, herbicides
- Poor Water Quality e.g. low dissolved oxygen, high levels of ammonia, nitrite or CO2
2. Infectious causes e.g. pathogens such as viruses, bacteria, fungi and parasites.
Check out these links below to learn more about some non-infectious causes of aquaculture diseases:
Once you have checked the links on non-infectious causes of aquaculture diseases — complete the following tasks by writing a comment:
- Summarise the information you gained from reading these articles.
- Was there any aspects you didn’t understand or want further clarified?
- How can fish farmers minimise stock losses due to non-infectious diseases?
8 responses so far ↓
Wow! some good links here that will extend the last couple of elluminate sessions. I will look forward to reading them in detail and adding some comments.
@Peter Glad to see your comment worked well. Look forward to how you go with the readings and I will write the next post later in the week.
Diseases in Aquaculture: Non-Infectious Causes
Without going into detail, information I have gained from these readings is that diseases in aquaculture are a critical aspect of the industry to monitor and prevent whether on a multi million dollar prawn farming venture or a backyard goldfish pond. The importance seems to lead to prevention rather than treatment and I am thankful that our strict quarantine laws and geographical isolation in Australia has limited our exposure to some of the infectious diseases affecting stock in other parts of the world. e.g. white spot disease in prawns.
It was interesting to read about some of the non infectious diseases and be able to relate my understanding of water quality to the diseases that can occur in aquaculture stocks. I can see how excessive nitrite levels can lead to brown blood disease and depleted DO levels can cause large scale fish kills but I didn’t realise that gas supersaturation and gas bubble disease could be a problem that requires monitoring. Is this a common condition? Have you ever had any first hand experiences with this?
Minimizing stock losses due to non infectious diseases must start at maintaining optimum water quality. This in my opinion is the most critical area to control as other variables like feed rates, stock density, environmental conditions and other localised impacts such as runoff from neighbouring farms or waterways all have an effect on water quality and thus fish health. Secondly, farmers must monitor their stock regularly to notice any change in appearance or behaviour and be able to take action before a problem escalates and avoid risking their entire stock.
hi sue thanks for the hekp and cant wait to be fully involved.
Well just read the three articles,lots of information to obsorb and just goes to show how in depth this fishy business can go.Look forward to more articles.
@Peter Yes as you point out it is important to prevent diseases regardless of size of the farming operation and prevention is always better than having to treat/deal with a disease outbreak. Hopefully we maintain our relatively disease free status however with increased production there is increased chances of new diseases occurring.
Gas bubble disease has been a problem in our training facility because the bore water contains high levels of CO2. What happens is the gas bubbles often form in their eyes leading to loss of eyes. Sometimes you will see fish with missing eyes.
Monitoring the stock everytime you interact with them i.e. when you feed them or clean their tanks is one of the best way to watch out for problems.
@Papa Good luck and don’t hesitate to contact me if you get stuck.
@Scott I totally agree there is a lot to absorb. I tried to choose 3 articles that were good and provided some extra information.
Hey I just had my 4 year old in here asking all sorts of questions about fish,she pretty much is againts eating anything alive,I showed her around this website as well as one where they are off on a field trip and there are great whites in the Video.She said if we be nice to the shark they wont eat you well I just said its a good idea to watch them from a distance.
On the topic of Fish kills by low DO.
If I had a pond that was around 20mtrs by 20mtrs and the depth was say 5mtrs,the weather is always in the upper 30s and very Humid with the occasional downpour of rain.This rain would not have any cooling effect but can cause a lot of runnoff from Properties nearby.Would it be best to have the water exchanged from a pond that is nearby and take the water that is exchanged from the lower parts to ensure you are getting cooler water rather then taking the warmer surface water.Also would it be better to aerate the water as much as possible during the curculating process,as this would assist with managing the DO levels as well as cooling the water to most optimum levels.
I am of the assumption that any movement of water can decrease its Temp and assist with DO levels??
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