Dr Maheswarudu: One of the important factors is the absence of a sea farming policy and guidelines till now by the Government. The Tamil Nadu Fisheries Department has drafted a policy quite long back. But so far no announcements. The other important factor is trust among the sea farmers (?). Apart from harsh weather conditions, poaching is one of the problems. Conflicting arguments arise frequently between the traditional fishers and sea farming groups. Continued availability of seed and feed may be also considered as other factors. This is true recently as cobia seeds are not available from the recognized hatcheries for the past few months for farming.Thanks for your concern. Dr Lipton

1) Feed made from fishmeal is not sustainable in the long run. Feed manufacturing companies import fish meal in India, as the country doesn't have the natural potential to have its own fish meal. 2) As a  part of feed is wasted, there are chances of pollution of the aquatic media. 3) If any cultured fish escapes into the wild, that would be disastrous to the gene pool of the natural population. 4) Vietnam,Thailand, Australia & Indonesia have established many hatcheries for supply of culturable varieties of seeds, it is a great potential for open sea cage culture in India. It appears that CIBA has succeeded in establishment of Indian Sea Bass hatchery, still there are many other varieties in which even the maritime state fisheries departments have not gone into their establishment. This is a severe drawback. 5) Respective state fisheries departments have still not identified which are the "no culture zones" looking into the navigational & shipping lanes, which may interfere with culture practices. 6) The cage culture zones has to be outside the neritic zone, otherwise it will interfere with the traditional capture fisheries & habitats of the neritic zone. 7) In future Kappaphycus culture is going to demand more of space, which would be in head on competition with cage culture of fish.  

Dr. Lipton Sir

Thanks for your valuable   inputs.

Dr. Trivedi Sir

Availability of fishmeal for aquaculture industry is a global concern and it is also causing non availability of fish for commonman consumption. Alternate protein source from agriculture based origin, for replacement of at least 50%  fishmeal in Aquaculture industry has to be evaluated. Aquatic pollution can be addressed by determining carrying capacity of a concern waterbody. Thank you for your active participation and concern inputs.

Dr. Gidda Maheswarudu

Daer Dr,. Maheswarudu, This is my opinion.-Besides the lack of  adequate seed and feed, the major limiting factor is lack of confidence in fish farmer about the  net return as cage farming in sea is prone to damage due to  harsh weather, and poaching. 

Dr. Kaladharan

Poaching can be addressed as a management measure and damage due to harsh weather can be reimbursed through insurance of crop.

Dr Maheswarudu:In my opinion it is also necessary an automatic feeding system which foresee the daily intake based on body weight, water temperature and dissolved oxygen, And to correct the daily supply of feed according to the daily weight gain and feed conversion. Thanks Dr. Agostinho

Dear Dr. Gidda,

I'm agree with Dr. Claudio.

Dr. Claudio and Dr. Shahram Dadgar

Your suggestions are welcome and thanks for the same.

Sir,

In open sea cage farming aquaculture,  the following points are considered concern for commercial fish production. 

i) In site selection -  the water depth, water current, wind speed and water velocity are considered as threats. 

The selected site, not nearby industrial area and effluents discharge area. 

The selected site for away from the fishing harbour to avoid the local conflict  and avoid the navigational area, fish spawning, and nursery zone. 

ii) the optimum size seed stocking (i.e 100g cobia seed is suitable for open sea cage farming),and the seed availability 

if the stocking size less than optimum leads to mass mortality within short periods/ subsequently mortality occurs

iii) the higher feed cost, 

Among the operating cost, feed alone accounts min. of 55- to 60% to total cost. Maximum profit occurs only by cost minimization. To reduce the production cost an alternative feed is required.

The cost of feed reduction is possible by practicing the alternative day feeding trials. (i.e day, two days once, three days once and weekly five days) if the growth rate is significant between regular feeding and alternative day feeding, the feed cost reduced about 50% from the exist.

iv) the fastest rate of disease spread speed

It's an open water system, therefore difficult to control and by giving treatment can partially save. Therefore, disease surveillance is more essential and a number of frequencies should be higher.

For commercial scale production, a consultancy/filed expert is essential for successful production rather than theoretical knowledge.  These are considered as the potential threat in open sea cage farming.

Thank you

RK

Dear Radhakrishnan Kalidoss

Do you think reducing feeding frequency, as you suggested, will yield optimum growth especially in fast growing shellfish and fin fish.

All the best

Sir,

In this regards, I do not have real field experiences. But, this work has done in tilapia species in Philipines at pond and cage (freshwater) level. They found that alternative day feeding has higher FCR and better survival with good yield as compared to daily feeding practices. Up to my knowledge, so far no work in open sea cage culture at the global level. I guess, this work needs to be done in open sea cage farming. Herewith, I attached two papers two paper related to alternative day feeding practices for your view.

With best,

RK

Dear Radhakrishnan Kalidoss

Your suggestion skipping feeding strategy is most appropriate to tilapia cage culture in reservoirs as it improves economics as well as mitigates the pollution caused by excessive feeding, leading to promotion of   public health because reservoirs are main source for drinking water. The effect  of skipping feeding strategy has to be evaluated in marine fin fishes and shell fishes.

All the best

Sir,

Well said (The effect of skipping feeding strategy has to be evaluated in marine fin fishes and shell fishes.)