ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00131.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTResults of 32 collection cruises forPenaeus setiferusadults over a 3‐year period in the northwestern Gulf of Mexico are reviewed to document incidence of capture of mature females, mating incidence by time of day of capture, and larval production from natural and artificial inseminations. Mean number of eggs per spawn by year for natural inseminations ranged from 197,000–309,000 (n=160) and for artificial inseminations, 136,000–300,000 (n=174) for females averaging 38–45 g. Mean percent hatch for natural inseminations ranged from 35.3–72.8, and for artificial inseminations, 14.7–77.8. The percentage of females captured from 0900–1600 hours which were mated ranged from 0–13%, while 9–42% of those captured from 1600–2200 hours were mated. The strongest diurnal increase in mating activity occurred from 1600–1800 hours. Three mated conditions, characterized by 1) a complete compound spermatophore; 2) the “wings” or anterior portion of the spermatophore only; and 3) a sperm mass only, represented 28.4%, 38.3%, and 33.3%, respectively, at time of capture. A significant relationship was found between spermatophore stage and hour of capture (P<0.149), suggesting there may be a sequential breakdown of the sperma

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00132.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00133.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTExperiments conducted withPenaeus aztecus, P. setiferusandP. vannameicompared survival, metamorphosis and dry weight growth of larvae fed a variety of algal and animal food regimes. The major objectives were: (a) comparison of the nematodePanagrellus redivivusand the brine shrimpArtemiaas animal food sources and (b) comparison of effects of feeding diatoms (Skeletonema costatum and Chaetoceros gracilis) vs phytoflagellates (Isochrysissp. andTetraselmis chuii) with nematodes or brine shrimp nauplii added to the diet starting at the protozoea‐two or mysis‐one substage.Specific feeding regimes were identified for each shrimp species tested which would allow for total or partial replacement ofArtemiaas the animal food source, without reducing production results. However,Panagrellus redivivuswas found to be less versatile thanArtemianauplii in terms of overall nutritional value to the shrimp larvae. The superiority of using two diatom species vs two phytoflagellate species as an algal food source for penaeid shrimp larvae demonstrated in earlier experiments was confirmed.The results strongly suggest that evaluation of rearing regimes used for production of penaeid postlarvae should include growth in terms of dry weight, as well as survival and rate of metamorpho

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00134.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00135.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTThe first experiment of this study was conducted in 1981 usingPenaeus vannameifrom Ecuador. Animals weighing an average of 3.8 g were stocked in seven earthen ponds (163 m2) at an average density of 9.2 animals/m2. The shrimp in two of the ponds were fed Ralston Purina MR20 shrimp feed daily. The remaining five ponds were not fed, but were enriched with cattle manure plus inorganic fertilizer. After 62 days the average body weight was 20.3 g. The average weekly weight gain and average survival were 1.82 g and 54.05% respectively for ponds fed commercial feed, and 1.89 g and 59.9% for ponds enriched with fertilizer.The second experiment was conducted in 1982, usingP. vannameifrom Costa Rica. Four ponds (163 m2), Group 1, were stocked with 6.5 g animals at a density of 7.1 animals/m2. An additional four ponds as Group 2 were stocked with 3.2 g animals at a density of 9.4 animals/m2. One pond from each group received one of the following four treatments: no external inputs, feeding with MR20 feed or fertilizing with cattle manure 0.5 kg/m2or 1.0 kg/m2. After 77 days the average weight was 17.88 g in Group 1 and 16.93 g in Group 2. There was a significant difference in growth rate between Group 1 and Group 2. Survival for all treatments was greater than 71.4% and averaged 80.7%. Water quality was monitored in both experiments. Water temperatures were higher in experiment 1 than in experiment 2. No correlations have been drawn between growth rates, water quality parameters, and treatments, in either experiment.In conclusion,P. vannameican be raised in cow manure‐enriched ecosystems at a stocking rate of 9.4 animals/m

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00136.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTAn inexpensive and simple mechanical size grader for freshwater prawns was developed, utilizing a pair of diverging rollers (114 mm diameter and 90 cm length). Five machine variables were studied using a two‐level fractional factorial sequential search technique. Optimum roller speed was 100 RPM, with an optimum roller incline of 10 percent. Space between rollers was 20 mm at the entrance and 29 mm at the exit. At a recomnended feeding rate of 3 prawns every 3 seconds, 90 percent correct sorting of market sized prawns was achieve

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00137.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTSince 1973, the Centre Océanologique du Pacifique has been conducting, in its Tahitian and New Caledonian facilities, tropical penaeid shrimp rearings. Up to now, among the different species tested,Penaeus mnodon, P. stylirostris, P. indicusandP. vannameihave been selected and currently cultured for several generations.P. monodonis a fastgraving species especially adapted to tropical semi‐intensive culture conditions with a 2–3 tons/ha/year production from postlarvae.P. stylirostrisis particularly suitable for cultures at lower temperatures (22–28°C). Yields are similar to those obtained withP. mnodon. P. indicus, a smaller species, is easily bred in captivity. In semi‐intensive cultures, production is slightly inferior (1.5‐2 tons/ha/year). However,P. indicustolerates high density culture conditions (>100/m2), though at a lower growth rate (yields, 15 tons/ha/year).P. vannameiexcels in intensive systems. Production, obtained in small volumes (10 m3), averages 40 tons/ha/year but results in larger volumes (100 to 1,000 m3) are

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00138.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00139.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTThis analysis utilized the production data obtained in 1982 from ponds at the Cedar Bayou Texas A&M Mariculture Facility, east of Baytown, Texas. The Aquaculture Budget Simulation System developed at Texas A&M University was applied to create budgetary information including the net return, economic profit, break‐even quantities and prices, and net present values over a 10‐year horizon. This information was used to evaluate the economic feasibility of different stocking strategies at a proposed 76‐ha commercial penaeid shrimp culture operation. The stocking strategies consist of monoculture ofPenaeus stylirostrisat 10 and 20/m2respectively and polyculture ofP. stylirostriswithP. vannameiat two ratios (3:1 and 1:3) with a total density of 20/m2.The results indicated that only the polyculture of 75%P. vannameiwith 25%P. stylirostrisis economically profitable. This stocking strategy yields an economic profit of $54,589 for the first year of operation. The break‐even production of 1,526 kg/ha is less than the expected annual production of 1,919 kg/ha. The break‐even price of $6.11/kg is less than the market price of $8.23/kg. The net present value is $839,424 over 10 years considering the beginning $20,000 cash and 20% of the total investment as owner's investment. The payback occurred following the second year'

ISSN:0735-0147    

DOI:10.1111/j.1749-7345.1984.tb00140.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY