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The effect of multiple-batch channel...

Southworth, Brent E.

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The effect of multiple-batch channel catfish Ictalurus punctatus stocking density and feeding rate on water quality, production characteristics and costs.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	The effect of multiple-batch channel catfish Ictalurus punctatus stocking density and feeding rate on water quality, production characteristics and costs./
作者:	Southworth, Brent E.
面頁冊數:	110 p.
附註:	Source: Masters Abstracts International, Volume: 46-05, page: 2551.
Contained By:	Masters Abstracts International46-05.
標題:	Agriculture, Fisheries and Aquaculture. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=EP25772

The effect of multiple-batch channel catfish Ictalurus punctatus stocking density and feeding rate on water quality, production characteristics and costs.
Southworth, Brent E.

The effect of multiple-batch channel catfish Ictalurus punctatus stocking density and feeding rate on water quality, production characteristics and costs. - 110 p.

Source: Masters Abstracts International, Volume: 46-05, page: 2551.

Thesis (M.S.)--University of Arkansas at Pine Bluff, 2005.

Technological improvements have allowed aquaculture and catfish production to become more intensive over time. With this increase in production intensity, catfish producers must seriously evaluate interactions among factors related to stocking density, feeding rate and water quality on costs and net returns. Little research has been done with multiple-batch production practices to quantitatively define these relationships. Twelve 0.1-ha ponds were stocked in multiple-batch with 10-15 cm fingerlings at either 8,600, 17,300, 26,000 or 34,600 fish/ha along with 2,268 kg/ha of carryover fish ranging from 0.37-0.45 kg/fish. The study consisted of three replications per treatment to constitute four treatment groups. Fish were fed daily to apparent satiation with a 32% floating commercial catfish feed. Nitrite-N, nitrate-N, total ammonia nitrogen, chlorophyll a, total nitrogen, total phosphorus, chemical oxygen demand and Secchi disk were monitored monthly, chloride three times during the study, pH weekly, and temperature and dissolved oxygen were measured twice daily. In addition, nitrite, total ammonia nitrogen, Secchi disk visibility and total alkalinity were measured in two-week intervals. Total hardness was measured for the source water and at the midpoint of the study. Weather station data were used to determine the effects of water temperature, barometric pressure and photosynthetically active radiation (PAR) on daily feed consumption. Ponds were harvested after a 196 d culture period (5 April--17 October 2005). The overall costs of producing channel catfish at different stocking densities and the respective effect on net returns were estimated. Fingerling (< 0.95 kg), carryover (≥ 0.95 kg), marketable (≥ 0.57 kg) and sub-marketable (< 0.57 kg) mean weights at harvest indicated no significant difference due to stocking density. Fingerling and carryover growth (g/d) was not significantly different. Gross, net and net daily yields showed no significant differences at different stocking densities. However, net yield was highly correlated with mean (r = 0.98) and maximum (r = 0.85) daily feeding rates. Carryover and marketable yield was not significantly different due to stocking density. Fingerling and sub-marketable yields increased as stocking density increased with significant differences between the two highest and the two lowest stocking densities. Mean fingerling survivals ranged from 24 to 36%, whereas mean carryover survivals ranged from 77 to 94%. However, survival rates of both size groups were not significantly different. Mean and maximum daily feeding rates ranged from 40-53 kg/ha/d and 123-188 kg/ha/d, respectively and were not significantly different. Feed conversion ratios averaged 1.75 and were not significantly different among the different stocking densities. Few significant differences in water quality were found at sampling periods. Similarly, water quality variables averaged across the production season showed no significant differences among stocking densities. Net returns varied widely across the different stocking densities, with the highest net return at 26,000 fingerlings/ha. Breakeven prices to cover both variable and total costs were lower at the higher stocking densities. Weighted average breakeven prices were Subjects--Topical Terms:

1020913
Agriculture, Fisheries and Aquaculture.

The effect of multiple-batch channel catfish Ictalurus punctatus stocking density and feeding rate on water quality, production characteristics and costs.
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245 1 4 $a The effect of multiple-batch channel catfish Ictalurus punctatus stocking density and feeding rate on water quality, production characteristics and costs.
300 $a 110 p.
500 $a Source: Masters Abstracts International, Volume: 46-05, page: 2551.
502 $a Thesis (M.S.)--University of Arkansas at Pine Bluff, 2005.
520 $a Technological improvements have allowed aquaculture and catfish production to become more intensive over time. With this increase in production intensity, catfish producers must seriously evaluate interactions among factors related to stocking density, feeding rate and water quality on costs and net returns. Little research has been done with multiple-batch production practices to quantitatively define these relationships. Twelve 0.1-ha ponds were stocked in multiple-batch with 10-15 cm fingerlings at either 8,600, 17,300, 26,000 or 34,600 fish/ha along with 2,268 kg/ha of carryover fish ranging from 0.37-0.45 kg/fish. The study consisted of three replications per treatment to constitute four treatment groups. Fish were fed daily to apparent satiation with a 32% floating commercial catfish feed. Nitrite-N, nitrate-N, total ammonia nitrogen, chlorophyll a, total nitrogen, total phosphorus, chemical oxygen demand and Secchi disk were monitored monthly, chloride three times during the study, pH weekly, and temperature and dissolved oxygen were measured twice daily. In addition, nitrite, total ammonia nitrogen, Secchi disk visibility and total alkalinity were measured in two-week intervals. Total hardness was measured for the source water and at the midpoint of the study. Weather station data were used to determine the effects of water temperature, barometric pressure and photosynthetically active radiation (PAR) on daily feed consumption. Ponds were harvested after a 196 d culture period (5 April--17 October 2005). The overall costs of producing channel catfish at different stocking densities and the respective effect on net returns were estimated. Fingerling (< 0.95 kg), carryover (≥ 0.95 kg), marketable (≥ 0.57 kg) and sub-marketable (< 0.57 kg) mean weights at harvest indicated no significant difference due to stocking density. Fingerling and carryover growth (g/d) was not significantly different. Gross, net and net daily yields showed no significant differences at different stocking densities. However, net yield was highly correlated with mean (r = 0.98) and maximum (r = 0.85) daily feeding rates. Carryover and marketable yield was not significantly different due to stocking density. Fingerling and sub-marketable yields increased as stocking density increased with significant differences between the two highest and the two lowest stocking densities. Mean fingerling survivals ranged from 24 to 36%, whereas mean carryover survivals ranged from 77 to 94%. However, survival rates of both size groups were not significantly different. Mean and maximum daily feeding rates ranged from 40-53 kg/ha/d and 123-188 kg/ha/d, respectively and were not significantly different. Feed conversion ratios averaged 1.75 and were not significantly different among the different stocking densities. Few significant differences in water quality were found at sampling periods. Similarly, water quality variables averaged across the production season showed no significant differences among stocking densities. Net returns varied widely across the different stocking densities, with the highest net return at 26,000 fingerlings/ha. Breakeven prices to cover both variable and total costs were lower at the higher stocking densities. Weighted average breakeven prices were $1 .50, $1 .58, $1 .32 and $1 .38/kg for densities of 8,600, 17,300, 26,000 and 34,600/ha, respectively. In spite of the higher proportion of sub-marketable fish in the higher densities, the higher yields and a similar average weight resulted in lower breakeven prices. This study found few significant differences in production and water quality parameters despite testing a variety of fingerling densities. The weight of carryover fish (stocked at a constant weight) may have had an effect on both production and water quality parameters, outweighing any effect of fingerling density. This study suggests that managing ponds based on the population structure of carryover fish maybe more important to overall production efficiency than strictly focusing on fingerling stocking densities, in multiple-batch production.
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791 $a M.S.
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