List one problem associated with composite fish culture.
Answers
Answer:
Biological Problems:
Biological hazards arise from the existence of weeds, predatory fishes, insects and snakes in the culture ponds.
These problems can be controlled if sufficient measures are taken before stocking fishes in between successive cultures.
Aquatic weeds, if any found in the pond can be very effectively controlled by the introduction of weed eating fishes like grass carp and Puntius species.
management problem:
It is always necessary to maintain at least 2 m of water depth in the pond.
Serious drought severely affects the level of the water in the rain-fed ponds. Alternative sources of water supply like tube-wells could be of helps in fighting against the drought.
Heavy rain and flood cause serious damage to the ponds by breaking the dykes or over flooding them. In both the cases, the fish escape from the pond.
harvesting problem:
It is essential to harvest the fish stock before the growth rate of the fish for the invested inputs such as feed and fertilizers start declining.
The nutritive value of water for feeding the fish cannot be increased after a certain stage.
Differential growth complicates the harvesting program and it is suggested that, if the harvesting times are very much difficult to synchronize in a community of fish even after careful manipulation of stocking ratio and density, partial harvesting may be resorted.
The sale prices of fish of less than a Kg is somewhat less as compared to those fish which weighs over a Kg or so. This also influences the harvesting programming and to get more profit, it is essential to consider this aspect also before harvesting.