Hot Weather And Poor Tilapia Egg Production II

The Tilapia Group discussion goes on with suggestions on how to overcome them in preparation for the future when abnormally high temperature occurs again. Here is the continuation....

[tilapia] Re: Hot weather and poor tilapia egg production

From:	Cristobal Gaston
To:	tilapia@yahoogroups.com

Hello Jo and hi to all.

My experience this last dry season was exactly like yours and I would like to be better prepared next season just in case. I wonder if water hycinth can help shade the sun's heat if grown in the breeder pond but outside of the hapa nets. 

[tilapia] Re: Hot weather and poor tilapia egg production

From:		Jose Mari De Guzman
To:	tilapia@yahoogroups.com

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Hello to all!
Adding vegetation on the water surface will cause a shading effect and perhaps 
lower down temperature a bit. However, it will also limit the contact of your 
water to the atmospheric oxygen thus reducing the O2 level in the water. The O2 
saturation level diminishes as the temperature rises above optimum and O2 
consumption of fish is also high due to increased metabolism.
Jom

 [tilapia] Re: Hot weather and poor tilapia egg production

From: Warren A. Turner
To: tilapia@yahoogroups.com
 Subject: Re: Hot weather and poor tilapia egg production

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Hi Ramon,

Hot weather is not a problem with fry, as survival is highest then. It is
only a problem for broodstock (and possibly grow-out) spawning. I think
plankton in the water helps absorb energy from sunlight and so the water
surface gets very hot. We do fertilized with inorganics to keep the water
green, but this is not related to reducing temperature. All of the fish are
kept in shallow hapas and so there is not much scope for them to escape down
deep. Deep ponds are not practical to work in.

Best regards

Warren

[Tilapia] Re: Hot weather and poor tilapia egg production

From:	Ramon Macaraig
To:	tilapia@yahoogroups.com

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Dear Warren,

Thanks for the clarification. What you said about fry survival rates in elevated 
temperatures is true. We are observing the same thing in milkfish and grouper 
fry. 

For the broodstock environment, we may propose approaches that would minimize 
stress factors. Some things that come to mind are open field breeding (without 
hapas) during the hot months, establishing a refuge section in the pond where 
some shade and oxygen mixing by mechanical devices can be installed for hot 
days, pumping colder waters at certain times of the day. Or if the costs of such 
installations and activities are higher than what the incremental survival rates 
from the status quo system can give, maybe stop the breeding temporarily, rehab 
broodstock health and come back strongly when the conditions would favor 
productive spawning.

Best regards,

Ramon M. Macaraig

[tilapia] Re: Hot weather and poor tilapia egg production

From: Warren A. Turner
To: tilapia @yahoogroups.com
Sent: Wed, September 29, 2010
Subject: Re: Hot weather and poor tilapia egg production

Moving to high altitude might not be as funny as you think. I knew a guy who started putting broodstock in orange orchard reservoirs in Nakhon Ratchasima. They were at slightly higher altitude and there was continual run-off of cool water from the hills that ran continually through the reservoirs. He then put in some floating cages, a small hatchery, as staff member and picked up the swim-up fry every 15 days. He was hoping we would buy them, as he had excess to his needs. The water was lovely and cool during the hot season when I visited.

Best regards
Warren

[tilapia] Re: Hot weather and poor tilapia egg production

From: jobaldia@yahoo.com

To: tilapia @yahoogroups.com

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Hi Warren:

I was thinking of my case. When you are operating a 5 ha Tilapia hatchery/nursery farm with all the hatchery building, tanks, pond development and all the investments, and profitability is alright except on rare odd times like El nino for example, isn't suggesting to move to another place hilarious? The guy you mentioned must have started in that place.

I bet that egg production and growth of fish in high altitude will also be severely affected during the cooler months of December to February especially if the water comes from the run-off from the hill. I guess one cannot have everything!

Jobaldia

From: warren.namsai 
 To: tilapia @yahoogroups.com

 Hi Jobaldia,

The guy had a hatchery with broodstock, hatchery, nursery, sales and his house. The broodstock he stocked at the orange orchard were at least 50 km away (maybe 100 km) and it didn't cost him much, as he didn't have to excavate. He just built a simple gravity, flow-through hatchery. I guess during the cold season he relied more on the stock at his home farm.

There is about 4 oC drop in temperature at 500m altitude compared to sea level. If you live next to a mountain, then it's a possibility, although better if you can achieve it on your own farm for management reasons.

Best regards

Warren

[tilapia] Re: Hot weather and poor tilapia egg production

From	Jose Abucay   To: tilapia @yahoogroups.com

Certainly transferring a hatchery is not like transferring a tent. However the problem maybe resolve by collaboration. A hatchery in colder location could produce the fry and transfer them to another farm in warmer location for nursery and hormone treatment. I think this does not sound impossible.

Jose S. Abucay 
College of Fisheries
Freshwater Aquaculture Center
Central Luzon State University
Science City of Munoz, Nueva Ecija, Philippines