Transferring
the tilapia from pond to pond using seine nets is an important part of the management
strategy being utilized at the farm in Venezuela. It is a labor intensive and
time consuming practice, but the dividends in terms of knowledge gained about
the growing crop is well worth the effort. In moving the fish, we can determine
the total number of fish in the pond and their average weight along with information
about their general well-being and health. From this data, we will be able to
extrapolate survival and actual food conversion ratios for the period. Further,
we will be able to adjust the quantity of feed to an exact known number of fish
in the system, which will result in better feed utilization and reduce the risk
of overfeeding. By splitting the crop, it also allows us to maximize space utilization.
The seining of the fish is a rather stressful event for the fish. The fish
are concentrated in high numbers in a very small area and oxygen levels decline
rapidly unless preventative measures are called on. A quick and efficient transfer
in the early morning hours eases the stress on the fish. Both supplemental oxygen
and fresh water input are important during this stage.
The fish are weighed by volume and samples counts are taken to ascertain the
average weight of the population. These fish have shown tremendous growth during
the fry to fingerling cycle. The picture to the right shows the harvest of the
farms first group of fish. These fish grew from a size of around 0.5 grams at
the time they were stocked, to the 60 gram average size in 44 days. This excellent
growth is attributed to the line of fish, the excellent water characteristics
of the site, good management and high quality feeds.