Water quality management in a marine fish hatchery system

Abentin Estim (2010) Water quality management in a marine fish hatchery system. Doctoral thesis, Universiti Malaysia Sabah.

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Abstract

Water quality is vitally important for any aquaculture system. The quality of water at intake point as well as changes in the quality as the water flows into the various sections of the hatchery require regular monitoring. The effect of fish in the hatchery tanks is brought to bear on water composition by release of metabolic waste and degradation of unconsumed feed among other factors. Unless remedial action is taken, water quality is impaired and this in turn produces adverse influence on growth and survival of the fish. Obviously, in order to maintain healthy operation of the aquaculture system, certain parameters have to be identified, examined and their range regulated within the tolerance limits of the fish in captivity. This thesis was designed to generate information on dynamics of water quality in a marine finfish hatchery and environment-friendly methods which can be applied to manage the water quality. The parameters monitored included temperature (0C), dissolved oxygen (mg/L), pH, salinity (0/00), total suspended solid (mg/L), turbidity (mg/L), total alkalinity (mg CaCO3/L), total carbon dioxide (mg/L), NH3+NH4-N (mg/L), NOr N (μg/L), NOrN (mg/L), PO4-P (mg/L), Cd (μg/L), Cr (μg/L), Cu (μg/L), Fe (μg/L) and Pb (μg/L). As a result of intensive studies the range of variations in the water quality parameters was established, the problems affecting captive fish were identified and remedial actions worked out. Water quality remediation involved application of biofilters, mainly the Aquamat™ and biodynamic integration of aquaponic system with the aquaculture units. Aquamat™ is an innovative product fabricated from highly specialized synthetic polymer substrates that provided in situ biofiltration while the culture was under progress. The aquaponic system provided a natural filtration of water for the fish and the fish waste was made use of in growth of plant biomass. Seaweeds used as the plant component of the aquaponic system comprised of three varieties of Eucheuma namely, £ spinosum (brown and green colours) £ cottoni. Results showed that the seawater quality of the six sections in the hatchery was within the suitable range for marine fish culture activity. However, two sections, namely, culture tanks and the waste water required improvement for reducing NHrN+NH4-N and NOrN concentrations. Aquamat™ reduced fish mortality, and concentrations of NHrN and total suspended solid. However, NO2-N and NOrN concentrations remained high, which suggested that the Aquamat™ could not remove all the dissolved inorganic nitrogen from the culture system. Aquamat™ provided surface area for larval fish to hide from cannibalism, for attachment of extra feed ingredients and fish waste, and for microbes to grow, which then enhanced nitrification process. In aquaponic experiment, specific growth rate and biomass yield of£ spinosum were in the range of 0.36 ± 0.11 % perday to 0.42 ± 0.13 % perday and 0.95 ± 0.27 g/day/m2 to 1.13 ± 0.32 g/day/m2, respectively. £ spinosum had the capability of reducing NH3+NH4 +, NO2 - and NO3- concentrations in culture systems. Combination biofilters of seaweed and coral rubble had higher NH3+NH4 + removal percentage. Based on these findings, a combination of Aquamat™, aquaponic and coral rubble was tested as a model of biointegrated, environmental-friendly and efficient aquatic food production system. In conclusion, this thesis yielded practically feasible water quality remediation systems that can contribute towards a low carbon sustainable aquaculture technology.

Item Type:	Thesis (Doctoral)
Keyword:	Water quality, Marine fish hatchery, Aquaponic, Aquamat and Biofilter
Subjects:	S Agriculture > SH Aquaculture. Fisheries. Angling > SH1-691 Aquaculture. Fisheries. Angling > SH20.3-191 Aquaculture > SH151-179 Fish culture > SH171-179 Diseases and adverse factors
Department:	INSTITUTE > Borneo Marine Research Institute
Depositing User:	DG MASNIAH AHMAD -
Date Deposited:	09 Feb 2024 15:41
Last Modified:	09 Feb 2024 15:41
URI:	https://eprints.ums.edu.my/id/eprint/38187

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