38 research outputs found
Water quality management in a marine fish hatchery system
No full textWater 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
Positioning of Aquaculture in Blue Growth and Sustainable Development Goals Through New Knowledge, Ecological Perspectives and Analytical Solutions
No full textSaleem Mustafa, Abentin Estim, Sitti Raehanah M. Shaleh, and Rossita Shapawi. 2018. Positioning of Aquaculture in Blue Growth and Sustainable Development Goals Through New Knowledge, Ecological Perspectives and Analytical Solutions. Aquacultura Indonesiana, 19 (1): 1-9. Aquaculture is undergoing a rapid phase of expansion as never before. Like any food-producing sector, there are environmental, social and economic implications of aquaculture development as well. It is imperative to identify actions and potential for promoting business ideas behind aquaculture systems that are in harmony with the environment even as this sector increases its contribution to food security and socio-economic welfare. This paper presents an in-depth analysis of the actual and potential role of aquaculture in supporting blue growth and achieving sustainable development goals. It emerges from the synthesis of information so generated that: 1) Aquaculture‟s key role in sustainable development goals deserves to be adequately documented, backed by facts and figures, 2) Aquaculture‟s contribution to each of the goals is qualitatively and quantitatively different, 3) Aquaculture is a diverse activity and, therefore, its impacts, especially from an environmental perspective, cannot be generalized across the whole sector, as these will vary with species, farming methods, environmental conditions at the location and the local socio-economic scenario. With its projected role in food security the aquaculture will continue to develop. However, this will be possible through scientific solutions focused on sustainability by informing best practices. As marine aquaculture moves further out to the sea new knowledge will be needed to understand environmental impacts and to support new farming systems. Similarly, data will also be needed to adapt aquaculture methods to changing climate. A systems approach to managing aquaculture is the way forward, a showcase of which is integrated multi-trophic aquaculture. The progress of aquaculture in meeting the sustainable development goals will require a monitoring mechanism that the relevant agencies need to put in place
Integrated multitrophic aquaculture
No full textThere has been a growing concern in recent years about the impacts of aquaculture on the environment and natural resource supplies. It is estimated that 85% of the phosphorus, 80-88% of the carbon, 52-95% of the nitrogen and 60% of the mass feed input in aquaculture ends up as a particulate matter, dissolved chemicals or gasses. Uncontrolled nutrients released by aquaculture operations harm the industry in at least three ways: reduced water quality, loss of valuable nutrients and adverse effects on the health of cultured organisms. This situation has to be corrected. The most prominent characteristic of some aquaculture production systems is the presence of biofilters, which helps in internally treating the water containing waste from the cultured organisms. The future of aquaculture must be based on the development of sustainable environment-friendly systems such as the Integrated Multitrophic Aquaculture. This provides an effective way of treating aquaculture water and can be done by bacteria, microalgae, macroalgae and suspension feeders
Types and abundance of macro and micro-marine debris at Sebatik Island, Tawau, Sabah
No full textThe amount of marine debris is increasing worldwide and has become a matter of serious concern. It is important to identify the nature of debris to understand the sources and to devise practically feasible methods for managing this problem. This study was carried out at Sebatik Island on the east coast of Sabah with the aim of examining the types and abundance of macro – and micro-debris. The observations covered a period of December 2015 – May 2016. Debris collected from different stations was compared. Transect line method was used to assess the stranded macro-marine debris (SMD). Evaluation of floating macro- debris (FMD) was done by surveys of the selected areas. Density separation technique was applied in order to extract the micro marine debris (MMD). Results showed 14 types of SMD and 9 types of FMD in the study areas. Three major types of SMD and FMD were discarded plastic, organic debris and plastic bottles. Four types of MMD recorded at the beach and mudflat areas were fragments, fiber, films and polystyrene. Based on the comparison between stations (S), S2 showed the highest abundance of SMD with 80 items m-2. Meanwhile, FMD at one location was as high as 94 items m-2. Station S3 has the highest of MMD with 22 items ml-1. Plastic formed (40%) of the SMD category whereas FMD constituted 42 % at the Sebatik Island. Small fragments and film were the most abundant of MMD (32 %). This study highlights the scale of the marine debris problem in Sebatik Island and calls for a comprehensive plan of action to protect the Island’s marine ecosystem services
Adopt and adapt nature’s design principles to create sustainable aquaculture systems
No full textSustainable development of aquaculture faces many constraints. An approach that offers solutions to these challenges is emulating nature’s patterns and strategies. There are many elements of sustainability employed by nature that can be adopted for aquaculture systems through necessary adjustments (or adaptations). Analysis of empirical data generated by a series of experiments on different aquaculture systems generated new knowledge of practical importance. An outcome of the analysis pertaining to two important aspects of aquaculture, the sex control in captive stocks of commercially important protogynous hermaphrodite grouper and the operation of integrated multi-trophic aquaculture systems is presented here. Both cases serve as outstanding examples of the relevance of examining and applying nature’s principles for finding sustainable solutions to aquaculture problems
Aquaponic application in a marine hatchery system
No full textSeaweeds of various species have been studied as nutrient biofilter for treating effluents from enclosed mariculture system since mid 1970’s. This study was conducted to determine the Euchuema spinosum (also known as E. den- ticulatum) effectiveness in reducing NH3+NH4+, NO2- and NO3- concentrations in the waste water of marine fish hatchery flow-through system. Four rectangular treatment tanks (0.5 x 0.55 x 0.5 m) were used in the experiment for 30 days. Each treatment tank planted with two E. spinosum cuttings with initial wet biomass of 50.28 ± 0.24 g and the waste water from the tank holding L. calcarifer juveniles flowed into each treatment tank using PVC pipe (ID = 25 mm) with an average flow-rate of 0.05 ± 0.01 L sec-1. The first treatment tank contained only seaweed (Swd) cut- tings, while the second and the third tanks were added with 8 kg substrate. The two substrates used were sand (S) and coral rubble (CR) with respectively sizes of 0.2 to 0.5 mm and 10 to 25 mm. A combination substrate of S+CR was added into the fourth treatment tank. Results showed that the water temperature ranged from 29.15 ± 0.86 to 29.31 ± 0.76 oC, pH ranged from 8.16 ± 0.13 to 8.22 ± 0.19 and salinity ranged from 30.135 ± 0.087 to 30.145 ± 0.091. The variance analyses of interaction factors (four treatment tanks X inflow-outflow) showed significantly different values (p<0.05) in terms of NH3+NH4-N concentrations. The NO2-N was also significantly different (p<0.05) in terms of inflow-outflow factor. This proved that the treat- ment tank efficiently removed the NH3+NH4-N and NO2- N. The highest removal of NH3+NH4-N and NO2-N was recorded in the CR+Swd treatment tank. No significant difference (p<0.05) of specific growth rate and yield of E. spinosum in the four treatment tanks was recorded. The average growth rate and yield of E. spinosum were 0.42 ± 0.12 % day-1 and 1.13 ± 0.30 g day-1 m-2, respectively in the Swd tank, 0.42 ± 0.13 % day-1 and 1.13 ± 0.32 g day-1 m-2, respectively in the Swd+S tank, 0.40 ± 0.13 % day-1 and 1.08 ± 0.31 g day-1 m-2 respectively in the Swd+CR tank, and 0.36 ± 0.11 % day-1 and 0.95 ± 0.27 g day-1 m-2 respectively in the Swd+S+CR tank. Besides, the new thal- lus of E. spinosum was slightly small and thin. Other algae such as Melosira sp. and Vaucheria sp, were noted to grow on the surface of four treatment tanks. This study sug- gested that a combination of coral rubbles and E. spinosum 26 are suitable for use in a hatchery seawater remediation of dissolved inorganic nitrogen
Use of coral rubble, aquamat and aquaponic biofiltration in the recirculating system of a marine fish hatchery
No full textA preliminary study on the effect of combination biofilters, including coral rubble, geotextile AquamatTM (Meridian Aquatic Technology, Silver Spring, MD, USA), and algal aquaponics in a marine fish recirculating system was investigated. AquamatTM is an innovative product fabricated from highly specialized synthetic polymer substrates. AquamatTM forms a complex three-dimensional structure that resembles seagrass in appearance, and has been used to support high stocking densities in fish culture ponds and enhance biological processes. In addition, coral rubble was used, and two seaweed species, Eucheuma spinosum and E. cottonii, were evaluated for their usefulness as aquaponic biofilters in a recirculating system. Results showed that the four different biofilters operating within the recirculating system were significantly different (P<0.05) in NH3-N and NO3-N concentrations. The lowest mean NH3-N concentration was recorded in the recirculating tank using AquamatTM + seaweed + coral rubble, while the highest mean NO3-N concentration was recorded in the recirculating tank using AquamatTM + coral rubble. Fish weight gain and survival rates were not significantly different (p<0.05) in the four recirculating systems. In the second experiment, three varieties of Eucheuma spp. grew poorly, and produced no noticeable effects on NH3-N, NO2-N and NO3-N concentrations. Eucheuma cottonii decayed in the early days, while the two varieties of E. spinosum decayed after 35 days. Once decayed, water quality impairment followed This study concluded that Eucheuma species were not suitable as a method of biofiltration in a recirculating culture system. While these seaweeds do remediate water quality, they themselves require a good environment to perform this role. When conditions are not optimal for the stocked organisms, the co-culture system can produce negative results. Follow-up investigation is needed to determine the suitability of such integrated aquatic systems for a large-scale fish production in recirculation system
Higher Education and Sustainable Development of Marine Resources
No full textMarine park is a designated area of the sea where
national regulatory authorities place limits on certain
human activities. Marine parks usually allow
multiple uses. Certain zones are protected for
preserving specific habitats for marine biodiversity
to achieve ecological sustainability while in
others activities such as recreational fishing, ecotourism,
snorkeling, and diving are allowed.
Large marine parks have open zones for fishing
and no-take zones where extractive activities such
as fishing, sand mining, and drilling are prohibited.
Generally, marine parks are considered
suitable places for gaining scientific understanding
and promoting environmental awareness
while safeguarding the benefits of indigenous
coastal communities.
Sea ranching is a type of marine farming in
which juveniles are released into the ocean where
they grow without containment structures. The
juveniles are generally produced in the hatcheries.
In some cases, wild-caught juveniles from one
area are also released into another area for stock
enhancement or creating a fishery resource. They
grow unprotected and without any assistance such
as feed from outside. The marine environment
provides the juveniles all the resources to grow
to be subsequently harvested. Sea ranching is
unlike mariculture where stocked species are
held in captivity, in cages, sea pens, or other
types of enclosures, and provided feed and other
requirements from external sources.
Nature-based solutions are human actions
aimed at sustainably managing the natural or
modified ecosystems. Such solutions include
measures to protect and restore the ecosystems
and are inspired by nature. In the context of
oceans, the nature-based solutions are systematic
and informed interventions that are resource-efficient
and help in building resilience. This concept
is based on the understanding that healthy ocean
provides more ecosystem services that benefit the
humanity
Water quality remediation using aquaponics sub-systems as biological and mechanical filters in aquaculture
No full textThis paper presents data obtained through trials on small-scale aquaponics sub-system which performs the roles of biological and mechanical filters for aquaculture water quality remediation. Aquaponics is a bio-integrated food production system, consisting of closed recirculating aquaculture combined with hydroponics. The trials were conducted on Nile tilapia (Oreochromis niloticus), and green beans (Phaseolus vulgaris) and the Chinese cabbage (Brassica rapa chinensis) over a period of 70 days. The results revealed that the system is more efficient in terms of plant growth and does not adversely affect the growth of captive stock of fish. Mean (± S.D.) values of water temperature, DO, pH, NH3-N, NO2-N, NO3-N and PO4-P during the trial were 25.2 ± 0.25 °C, 6.6 ± 0.13 mg/L, 7.14 ± 0.06, 0.23 ± 0.02 mg/L, 0.39 ± 0.22 mg/L, 0.89 ± 0.37 mg/L and 0.45 ± 0.04 mg/L, respectively. The average total weight gain by O. niloticus was 637.2 ± 8.49 g, and feed conversion ratio (FCR) was 1.47 ± 0.01 which indicated the efficiency of Nile tilapia in converting feed mass – a universally standard measure of efficiency of feed assimilation into weight gain, especially when there is no additional source of nourishment. High survival rate (95 ± 2.8%) was noticed during the trials. The average (±SD) values of biomass gain by P. vulgaris and B. rapa were 951.6 ± 1.6 g and 85.3 ± 13.4 g, respectively. The system was cost-effective and efficient in purging the toxic waste from water, resulting in remediation of water quality for the recirculating aquaculture system. This reflected the effectiveness of biofiltration which is currently assessed by its ability to completely remove the ammonia and minimize the generation of nitrite
Behavior and response of Japanese catfish (Silurus asotus) in captivity provided with an artificial microhabitat
No full textRearing of Japanese catfish (Silurus asotus) requires special considerations for designing of facilities and management. Information on its biology in natural environment provides ideas for developing suitable culture systems. For this species, underwater artificial microhabitat structures are needed to perform its normal behavior. The fish shows distinct preferences for some designs based on visual cues and its decision to make use of these structures is guided by other cues probably related to light and water flow. Microhabitat structures can make a real difference to managing stress of captivity in this species. Absence of a suitable structure causes ‘habitat bottleneck’ that develops aggressive behavior. However, the intraspecific antagonistic behavior gives way to social tolerance among conspecifics. Microhabitat metrics is important in addition to physical attributes of the structure so as to allow social grouping in the fish under favorable conditions
