time and an alteration in larval metabolism with higher energetic cost (Ismael etal. 2001). In view of the somewhat confusing results reported above, it may still be possible that brackishwater made from natural seawater may give better overall results in the rearing of M. rosenbergii larvae than brackishwater made from artificial seawater; this are requires further research for elucidation. The chemical composition of a simple artificial brackishwater used for the M. rosenbergii hatchery at the UNESP Aquaculture Center (Centro de Aquicultura da Universidade Estadual Paulista -CAUNESP) in Brazil is shown in Table 5.2. The average cost of producing 1 m3 of 12p.p.t. brackishwater in Brazil is aboutUS$ 17 but it is cheaper in the USA - about US$ 13°C. Upstrom, pers. comm. 2008).
The water preparation has been described in detail by Valenti et al. (1998). The salts are weighed and diluted individually with previously filtered freshwater. The resulting solutions are added to a tank following the order presented in Table 5.2 and mixed thoroughly using a PVC stirrer. After that, freshwater is added in order to attain 12 p.p.t. salinity. The final solution is maintained under strong aeration for 24 hours and the salinity adjusted, if necessary.
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Lets start by identifying what exactly certain boats are. Sometimes the terminology can get lost on beginners, so well look at some of the most common boats and what theyre called. These boats are exactly what the name implies. They are meant to be used for fishing. Most fishing boats are powered by outboard motors, and many also have a trolling motor mounted on the bow. Bass boats can be made of aluminium or fibreglass.