• Fisheries and Aquatic Sciences
• /
• v.17 no.1
• /
• pp.1-11
• /
• 2014

The Kenyan aquaculture sector is broadly categorized into freshwater aquaculture and mariculture. Whereas freshwater aquaculture has recorded significant progress over the last decade, the mariculture sector has yet to be fully exploited. The Kenyan aquaculture industry has seen slow growth for decades until recently, when the government-funded Economic Stimulus Program increased fish farming nationwide. Thus far, the program has facilitated the alleviation of poverty, spurred regional development, and led to increased commercial thinking among Kenyan fish farmers. Indeed, national aquaculture production grew from 1,000 MT/y in 2000 (equivalent to 1% of national fish production) to 12,000 MT/y, representing 7% of the national harvest, in 2010. The production is projected to hit 20,000 MT/y, representing 10% of total production and valued at USD 22.5 million over the next 5 years. The dominant aquaculture systems in Kenya include earthen and lined ponds, dams, and tanks distributed across the country. The most commonly farmed fish species are Nile tilapia Oreochromis niloticus, which accounts for about 75% of production, followed by African catfish Clarias gariepinus, which contributes about 21% of aquaculture production. Other species include common carp Cyprinus carpio, rainbow trout Oncorhynchus mykiss, koi carp Cyprinus carpio carpio, and goldfish Carassius auratus. Recently, Kenyan researchers have begun culturing native fish species such as Labeo victorianus and Labeo cylindricus at the National Aquaculture Research Development and Training Centre in Sagana. Apart from limited knowledge of modern aquaculture technology, the Kenyan aquaculture sector still suffers from an inadequate supply of certified quality seed fish and feed, incomprehensive aquaculture policy, and low funding for research. Glaring opportunities in the Kenyan aquaculture industry include the production of live fish food, e.g., Artemia, daphnia and rotifers, marine fish and shellfish larviculture; seaweed farming; cage culture; integrated fish farming; culture of indigenous fish species; and investment in the fish feed industry.

• ALGAE
• /
• v.37 no.2
• /
• pp.85-103
• /
• 2022

Korea is one of the most advanced countries in kelp aquaculture. The brown algae, Undaria pinnatifida and Saccharina japonica are major aquaculture species and have been principally utilized for human food and abalone feed in Korea. This review discusses the diversity, population structure and genomics of kelps. In addition, we have introduced new cultivar development efforts considering climate change, and potential carbon sequestration of kelp aquaculture in Korea. U. pinnatifida showed high diversity within the natural populations but reduced genetic diversity in cultivars. However, very few studies of S. japonica have been conducted in terms of population structure. Since studies on cultivar development began in early 2000s, five U. pinnatifida and one S. japonica varieties have been registered to the International Union for the Protection of New Varieties of Plants (UPOV). To meet the demands for seaweed biomass in various industries, more cultivars should be developed with specific traits to meet application demands. Additionally, cultivation technologies should be diversified, such as integrated multi-trophic aquaculture (IMTA) and offshore aquaculture, to achieve environmental and economic sustainability. These kelps are anticipated to be important sources of blue carbon in Korea.

• Korean Journal of Organic Agriculture
• /
• v.8 no.1
• /
• pp.79-88
• /
• 1999

In order top investigate the growth of water dropwort grown by sandculture irrigated with recirculated tilapia aquaculture water, these experiments were carried out. Fish(tilapia) production and biofiltration provided by sand cultured water dropwort(Oenanthe stolonifera DC.) were linked in a closed system of recirculation water. Water dropwort was irrigated with water drawn from the tilapia tank and drainage from sand beds was returned to the fish tank. The temperature, pH and EC of tilapia culture water were stable. The growth of water dropwort grown by sandculture with aquaculture water was normal. Microbial activity of the biofilterbed irrigated by tilapia rearing water was higher than that of biofilterbed irrigated by tapwater. The feasibility of an integrated, recirculatory system for concurrent production of water dropwort and fish with no additional fertilization application was demonstrated.

• Journal of Bio-Environment Control
• /
• v.8 no.3
• /
• pp.209-215
• /
• 1999

In order to develop facility for complex farming with aquaculture and vegetable nutrient culture and to investigate growth of tilapia and water quality in the channel type aquaculture system, these experiments were carried out. When tilapia(Tilapia nilotica) was reared in the channel type aquaculture system, Quality of culture water and growth of tilapia were normal. And the growth of tilapia in the channel type and round type aquaculture system was much the same. Channel type aquaculture facilities was applicable to the dual culture system for aquaculture and vegetable culture. Channel type integrated system was composed of aquaculture and sandculture bed, and it was thought that suitable size of the system was about 1.4m(width) $\times$ 1m(height) $\times$ 20m(length).

• Journal of Marine Bioscience and Biotechnology
• /
• v.4 no.1
• /
• pp.6-10
• /
• 2010

Indonesia is well-known as biggest producer of seaweed especially for Eucheuma and Gracilaria and also has huge potential resources and capability to develop seaweed cultivation and product. There are several provinces which have potential resources and have been contributing on seaweed production. The next challenge about seaweed production is using integrated system on brackishwater and marine aquaculture. Furthermore, about 2,000,000 ton of potential seaweed production is not explored yet. This article also tries to figure out some related aspects which are technical, economical and forecasting aspect. There is a disease which named "ice-ice" is one of the main problem and giving a new challenge in developing of problem solving for seaweed cultivation method. Economical parameters are also main important key to find out the feasibility of seaweed cultivation industry. In addition, the seaweed cultivation and production in Indonesia also have potential performance on biofuel resources as a part for solving the world problem on energy demand.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.60 no.1
• /
• pp.87-99
• /
• 2024

This study deals with the application of an artificial neural network (ANN) model to predict power consumption for utilizing seawater source heat pumps of recirculating aquaculture system. An integrated dynamic simulation model was constructed using the TRNSYS program to obtain input and output data for the ANN model to predict the power consumption of the recirculating aquaculture system with a heat pump system. Data obtained from the TRNSYS program were analyzed using linear regression, and converted into optimal data necessary for the ANN model through normalization. To optimize the ANN-based power consumption prediction model, the hyper parameters of ANN were determined using the Bayesian optimization. ANN simulation results showed that ANN models with optimized hyper parameters exhibited acceptably high predictive accuracy conforming to ASHRAE standards.

• Journal of Environmental Science International
• /
• v.23 no.10
• /
• pp.1703-1718
• /
• 2014

An eco-friendly integrated multi-trophic aquaculture (IMTA) farming technique was developed with the goal of resolving eutrophication by excess feed and feces as fish-farming by-products. A variety of seaweed species were tried to remove inorganic nutrients produced by fish farming. However, there have been few trials to use Sargassum fulvellum in an IMTA system, a species with a relatively wide distribution across regions with various habitat conditions, great nutrient removal efficiency and importance for human food source and industrial purposes. In this regard, our study tried to examine feasibility of using S. fulvellum in an IMTA system by analyzing growth characteristics of the species in an IMTA system comprising of rockfish (Sebastes shlegeli), sea cucumber (Stichopus japonocus) and the tried S. fulvellum (October 2011 - November 2012). We also monitored environment conditions around the system including current speed, water temperature and inorganic nutrient level as they may affect growth of S. fulvellum. S. fulvellum in the IMTA system, which were $15.72{\pm}5.67mm$ long at the start of the experiment in October 2011, grew to a maximum of $1093{\pm}271.13mm$ by May 2012. In September, seaweed growth was reduced to a minimum of $280{\pm}70.43mm$ in length. Then, S. fulvellum began to grow again reaching $325{\pm}196.19mm$ by November 2012. Wet weight of the seaweed was $4.01{\pm}1.89g$ at the start of the experiment and reached a maximum of $109.26{\pm}34.23g$ in May. The weight gradually declined to a low of $15.12{\pm}8.40g$ in September 2012. Weight began to increase once more, rising to $39.27{\pm}21.69g$ by November. During the experiment, the average velocity at the surface and the bottom was 6.5 cm/s and 3.4 cm/s, respectively. The water temperature ranged $5.0-23.5^{\circ}C$, which was considered suitable for growing S. fulvellum. Results of the study indicated no significant differences in inorganic nutrients between pre- and post-IMTA installation. It was thus concluded that S. fulvellum can be a suitable seaweed species to be used in an IMTA system.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.1
• /
• pp.107-113
• /
• 2012

Pollutants in aquaculture system effluent mostly originated from solid wastes including uneaten feed and excreta of cultured species. In this research, DAF(Dissolved Air Flotation) unit is suggested as an integrated solid control unit especially as a form of IIBG(Inline Injection Bubble Generation) process in aquaculture system. Solid removal performance of DAF unit was examined under various operation and salinity conditions with turbidity and suspended solid. Solid waste removal efficiencies were found to be affected by operation conditions including saturator pressure, recycle ratio, coagulant concentration. Solid removal efficiency was higher under higher saturator pressure and recycle ratio under which condition larger number of bubbles is generated. Coagulant is thought to have important role in creating bubble-particle aggregate by showing better removal efficiency with higher concentration. However higher saline water showed less effectiveness in removing solids by DAF(IIBG). Application of DAF(IIBG) process also showed additional effect in phosphate removal and DO(Dissolved Oxygen) supply. Phosphate existed in polluted water was removed up to 46% after treatment, which is thought to attribute to aluminium phosphate precipitation. And DO concentration was found to increase over 50% of initial saturation concentration after the injection of micro-bubbles. Through experiments on solid removal from aquaculture effluent, DAF(IIBG) process is estimated to be effective solid control method. This property can help aquaculture system being installed and operated simply and effectively.

• ALGAE
• /
• v.17 no.3
• /
• pp.187-194
• /
• 2002

A seaweed biofilter/production system of being developed to reduce the environmental impact of marine fish farm effluent in coastal ecosystems as a part of an integrated aquaculture system. Several known seaweed taxa and their cultivars have been considered as candidate biofilter organisms based on their species-specific physiological properties such as nutrient uptake kinetics and their economic value. Porphyra is an excellent cadidate and shows efficient nutrient extraction properties. Rates of ammonium uptake were maintained at around 3 ${\mu}moles{\cdot}g{\cdot}dw^{-1}{\cdot}min^{-1}$ at 150 ${\mu}M$ inorganic nitrogen at $10^{\circ}C$. Ulva is another possible biofilter candidate with an uptake rate of 1.9 ${\mu}moles{\cdot}g{\cdot}dw^{-1}{\cdot}min^{-1}$ under same conditions. A simple uptake/growth and harvest model was applied to estimate the efficiency of the biofilter/production system. The model was deterministic and used a compartment model structure based on difference equations. The efficiency of Porpyra filter was estimated over 17% of ${NH_4}^+$ removal from the contimuous supply of 100 ${\mu}mole{\cdot}l^{-1}\;{NH_4}^+\;at\;100l{\cdot}sec^{-1}$ flow rate.

• Korean Journal of Ichthyology
• /
• v.35 no.4
• /
• pp.305-312
• /
• 2023

Diet composition and feeding strategy of the largehead hairtail, Trichiurus japonicas were studied using 375 specimens collected by purse seine, set net fisheries and lure fishing from February 2021 to January 2022 in the southern sea of Korea. The anal length (AL) of these specimens was from 3.4~49.0 cm. T. japonicus fed majorly on Fishes (especially Engraulis japonicus) based on ranking index (%RI=99.3). Fishes were the main prey items for all size classes. T. japonicas also showed size-related dietary shift from E. japonicus to T. japonicus, Larimichthys polyactis and Engraulidae. Fishes were the main prey items for all seasons. The main fish prey during spring and summer was E. japonicus, but in the autumn and winter, the E. japonicus portion decreased, and T. japonicus, L. polyactis, and Engraulidae portion increased. T. japonicus were specialized feeders with E. japonicus as their dominant prey.