Showing papers on "Polyculture published in 1988"

The effect of fish species combination in fish ponds on plankton composition

Abstract: . In continuation of an experiment carried out in 1983, the effect of polyculture of bottom-feeding fish (common carp. Cyprinus carpio L.; tilapia hybrids, Oreochromis nilolicus (L.) ×O. aureus (Steindadner); and grey mullet, Mugil cephalus (L.) and a filter-feeding fish (silver carp. Hypopluhalmichtys molitrix (Valenciennes)) on the nannoplankton and netplanklon has been studied. This effect was analysed through principal component analysis. The results confirmed the linding of 1983 that the presence of silver carp in a pond, either alone or with bottom-feeding fish, results in a decrease in netplankton (phylo- and zooplankton) and an increase in nannoplankton which passes through the tiller apparatus of the fish. The effect of the silver carp seems to be related more to its numerical density than to its individual weight, since the effect diminished with the decrease in density during 1983–1985. It became least pronounced when the density was 400/ha. Bottom-feeding fish enhance the development of the larger nannoplankton by bringing up nutrients from the bottom, but reduce the number of the netplankton (mainly zooplankton) as compared to the control pond without lish. This effect was more apparent at a higher density of tilapia. but was masked when silver carp was present.

Canonical correlation analysis of relationships between management inputs and fish growth and yields in polyculture

Abstract: Canonical correlation analysis was used to study the influence of management factors on growth and yields in an experimental polyculture system. The major conclusions are: (1) yield of each species was affected mainly by its own stocking density, followed by interactions with other species; (2) the best yields and growth rates of tilapia were obtained with stocking weights of over 13 g and; (3) common carp, Cyprinus carpio L., was affected negatively by silver carp, Hypoihalmichihys molitrix (Valenciennes), density and positively by nutrient inputs. Its best performance was obtained at silver carp density below 1000/ha. Analyses of data from commercial production units are required to confirm these conclusions

Comparative Economics of Four Aquaculture Species Under Monoculture and Polyculture Production in Guam

Abstract: Financial analysis, which included breakeven, net present value, internal rate of return, present value index, payback period and financial ratios, was carried out on data from three aquaculture farms located on Guam. The analysis included four primary species, Macrobrachium rosenbergii, Chanos chanos, Clarias batrachus, and a hybrid Oreochromis mossambicus × O. niloticus, and two culture methods, monoculture and polyculture. Asian catfish, Clorias batrachus, monoculture showed the greatest capital return. The use of NPV, PVI, IRR, and payback period as decision criteria also resulted in the selection of Asian catfish monoculture from the alternative species and culture methods considered. Tilapia polyculture had the lowest return on investment (less than 1%) and required 92% of the total production to reach the breakeven point. The application of the analysis methods presented provide a means for management to reduce financial risks and make informed choices between alternative strategies.

Winter Polyculture of Channel Catfish and Rainbow Trout in Cages

Abstract: Under winter conditions in Oklahoma (1.0–20.0°C; average, 7.0°C), polyculture of caged channel catfish (Ictalurus punctatus) and rainbow trout (Salmo gairdneri) resulted in a significantly higher channel catfish weight gain (about 6.5%; P < 0.05) than that observed in channel catfish monoculture (–3.8% gain). Channel catfish also experienced increased growth as a function of proximity to rainbow trout in neighboring cages.

Preliminary experiments on monoculture of chanos chanos (forskal) and its polyculture with penaeus monodon fabricius

Abstract: Preliminary experiments on monoculture of milk fish, Chanos chanos and its polyculture with tiger prawn, Penaeus monodon were carried out in the grow-out pond system at Mariculture farm, Muttukadu near Madras. During the six-month rearing, C. chanos attained an average size of 234.6 mm (76.9 g) in the monoculture trial and 159.8 to 231.8 mm (39.0 to 90.9 g) in the polyculture experiments. In the case of tiger prawn, the growth was poor and the sizes recorded at harvest were 119.4 to 135.1 mm (12.8 to 17.8 g). The rate of recovery ranged from 8.4 to 87.0% for fish and 20.6 to 35.3 % for prawn. The reasons for poor growth and survival of fish and prawn in relation to environmental and other factors are discussed.

Nursery and grow-out operation for tilapia and carp

Abstract: Most researches conducted at the Binangonan Freshwater Station of the SEAFDEC Aquaculture Department were directed toward enhancing growth and survival of the young tilapia and carp in the nursery as well as increasing yields in grow-out cages, pens, and ponds. Studies included the culture and evaluation of phytoplankton and zooplankton as feeds of the tilapia and carp fry to fingerlings; determination of protein and amino acid requirements of young Nile tilapia; development of practical dry diets; evaluation of feeding regimes, feeding rates, and feeding frequencies ; and the use of fertilizers in nursery ponds. For the grow-out aspect, one of the earliest studies demonstrated the profitability of the monoculture of tilapia in cages which triggered the initial proliferation of tilapia cage culture by the private sector in areas near the Station. Subsequently, supplemental feeds were developed and evaluated; non-conventional feedstuffs were tested as feeds or feed components; and the growth rates of Nile tilapia fingerlings in cages at varying stocking densities were evaluated at three distinct rearing periods covering one year. Prior to the successful mass production of bighead carp fingerlings at the Station, studies on polyculture of tilapia, milk fish, and different species of carp were conducted in cages and pens with remarkable results. This led to the technology-verification projects on polyculture at various areas in Laguna Lake. With the availability of freshwater fishponds for research purposes, studies on polyculture in ponds were also conducted. D ow nl oa de d by [1 22 .5 5. 1. 77 ] f ro m h tt p: // re po si to ry .s ea fd ec .o rg .p h on F eb ru ar y 28 , 2 01 6 at 1 1: 58 A M C ST AQUACULTURE DEVELOPMENT IN SOUTHEAST ASIA

Nursery and grow-out operation and management of milkfish.

Abstract: This paper reviews the results of studies on the pond culture of milkfish Chanos chanos Forsskal at the SEAFDEC Leganes Brackishwater Station, Leganes, Iloilo since its establishment in 1973. Substantial contribution on the nursery system includes increased stocking density and survival through the use of nylon substrates, supplemental feeding with rice bran, the use of hatchery-reared and stunted fingerlings as alternative sources of stocks, and improvements in the acclimation process. Studies on monoculture and polyculture in grow-out ponds investigated the use of stunted fingerlings, kitchen or algal nursery ponds, stock manipulation techniques, increased stocking density using the plankton method, method frequency and quantity of fertilization, modular pond culture system, and initial findings on fish diseases. Constraints setting back increased production in the Philippines are discussed.

Polyculture of the Giant Malaysian Prawn and the Golden Shiner in Southwestern Louisiana1

Abstract: Juvenile prawns (Macrobrachium rosenbergii) were stocked at 37,050/ha and golden shiner (Noremigonus crysoleucas) fry at 321,100/ha into 16 earthen ponds at Rockefeller Wildlife Refuge, Grand Chenier, Louisiana. Four replicated treatments were tested: fed prawn monoculture, fed shiner monoculture, fed prawn and fed shiner polyculture, and unfed prawn fed shiner polyculture. The study lasted 149 days. There were no significant differences in growth between prawns fed in monoculture and prawns fed in polyculture (P > 0.05). However, fed prawns grew significantly larger (P < 0.05) than unfed prawns. Prawn survival in all treatments combined averaged 63%. Survival was significantly higher (P < 0.05) for fed prawns than for unfed prawns. Prawn yields averaged 533 kg/ha, when all treatments were combined. Yield was significantly higher (P < 0.05) for prawns grown with shiners and for prawns that received supplemental feed. Growth was significantly higher (P 0.05).

Further observations on the suitability of the marine fish farm at mandapam for the culture of milkfish and grey mullets

Abstract: The paper gives an account on the culture of milkflsh Chanos chanos and the grey mullet Valamugil seheli under mono and polyculture systems in the saltwater ponds at Mandapam during the period 19821983. Ponds of 2,400 mS (two ponds), 450 m2 (2 ponds) and 200m2 (3 ponds) were used for conducting the culture experiments. The stocks were fed with a supplementary feed. The growth of fish was better in polyculture experiments. The rate of production of Chanos chanos was 354-443 kg/ha with a survival of 73.2-79.9% in monoculture and 422-872 kg/ha with 56.7-70.0% survival in polyculture experiments. V. seheli indicated a production of 200-290 kg/ha and 67-89 kg/ha with the survival rates of 22-91 % and 13.3-20.7% in mono and polyculture experiments respectively.