Biology Reference
In-Depth Information
way to treat and recirculate wastewaters in extensive systems, but that a
multiple treatment combining a retention pond, foam fractionation and
micro-algae-bivalve fi ltration, is the best solution to treat all these forms
of wastes from intensive systems (Hussenot et al., 1998).
Cultivation of Macro-algae
To exploit fi sh-farm nutrients as a resource input, and at the same time to
reduce the risk of eutrophication, the high-temperature adapted red alga
Gracilaria lemaneiformis (Bory) Dawson from South China was co-cultured
with the fi sh Sebastodes fuscescens in North China in warm seasons.
Growth and nutrient removal from fi sh culture water were investigated
in laboratory conditions in order to evaluate the nutrient bioremediation
capability of G. lemaneiformis . Feasibility of integrating the seaweed
cultivation with the fed fi sh-cage aquaculture in coastal waters of North
China was also investigated in fi eld conditions. Laboratory seaweed/fi sh
co-culture experiments showed that the seaweed was an effi cient nutrient
pump and could remove most nutrients from the system. Field cultivation
trials showed that G. lemaneiformis grew very well in fi sh farming areas,
at maximum growth rate of 11.03%/ day. Mean C, N, and P contents in
dry thalli cultured in Jiaozhou Bay were 28.9 ± 1.1%, 4.17 ± 0.11% and
0.33 ± 0.01%, respectively. Mean N and P uptake rates of the thalli were
estimated at 10.64 and 0.38 µmol/g dry weigh/t h, respectively. An
extrapolation of the results showed that a 1-ha cultivation of the seaweed
in coastal fi sh farming waters would give an annual harvest of more
than 70 t of fresh G. lemaneiformis , or 9 t dry materials; 2.5 t C would be
produced, and simultaneously 0.22 t N and 0.03t P would be sequestered
from seawater by seaweeds. Results indicated that the seaweeds could be
suitable as a good candidate for seaweed/fi sh integrated mariculture for
bioremediation and economic diversifi cation (Zhou et al., 2006).
Fishery industry waste management has been one of the problems
that have the greatest impact on the environment (Arvanitoyannis and
Kassaveti, 2008). Fish and fi shery products are highly traded, with more
than 37% of total production entering international trade as different food
and feed products. Export of fi sh and fi sh products has increased by 32%
in the period 2000-2006. In 2006, more than 110 million tonnes (76.8%)
of world fi sh production was used for direct human consumption ( Table
8.3 ) ; 37.3% was in live and fresh form. Freezing is the main method of
processing fi sh for food use, accounting for 19.9%, followed by prepared
and preserved (11.3%) and cured fi sh (8.3%).
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