Environmental Engineering Reference
In-Depth Information
Chile smolts are called according to the production method as in-season smolt, late smolt,
and early smolt, depending mainly on broodstock´s photoperiod manipulation, chilled egg,
and imported egg. Therefore, smolt size regardless production method will normally range
between 90 g and 120 g. Furthermore, the transportation of smolt over 250 g is prohibited
and a certain small amount of smolts between 60 g and 90 g are produced by land-based
facilities.
Smolt production reached its historical peak production in 2007, presenting a significant
decrease in 2008 and 2009 (Figure 5), going from close to 400 million in 2007 to 160 million in
2009. This abrupt decrease in smolt production, mainly in Atlantic salmon, was caused by
the sanitary crisis. Commonly smolts are transported by road and wellboat to their final
ongrowing site in the sea. Due to the widespread FW areas in Chile fish are frequently
transported on land over 300 kilometres prior wellboat transportation. In addition, fish may
be transported to a lake or estuary then following land transport, wellboat and final
ongrowing destination. This has been a major challenge in welfare and adequate water
quality for the smolt transport systems.
300
Atlantic salmon
Co ho salmo n
Rainbow Trout
250
200
150
100
50
0
1995
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
Year
Fig. 5. Number of smolts produced (data available from year 1995). Source: Sernapesca
2011a
2.3.2 Seawater production
The technology used for salmonid on-growing in Chile is very similar to the rest of the
salmon producing countries, it is carried out in cages and today most operations are
automatized. At the end of the 1980s the sea cages were usually few square wooden
modules of approximately 1.100 m 3 (10x10x11) and located near-shore or in sheltered
waters. However, the size, location and type of cages have undergone profound
development during the 1990s and 2000s. Sea sites developed to over 12 modules of circular
high-density polyethylene cages of 12.725 m 3 (d. 30m) or square modules hinged steel cages
of 25.600 m 3 (40x40x16) provided with modern automated systems. Thus, large integrated
sites are also provided with pontoons including all comfortable living needs. The feeding
and fish-waste cleaning procedures have been changing enormously from 1980s. In the early
days of the salmon aquaculture, mainly hand control was performed that today is carried
out by automatic feeding systems, satellite and under water video devices. An important
development in anti-predators devices have been carried out due to huge losses caused by
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