摘要:

ABSTRACTThe production of fish protein concentrate and the aquaculture of fish in waste waters are two ancient technologies. Modern use of these technologies demands examination of their public health implications as they are adapted to modern needs of food production and waste processing. Though the ponding of wastes to meet safe discharge requirements has been observed to be efficient and economic, both chemical and microbiological factors potentially interfere with using waste waters to produce protein supplements for human consumption. Application of one or more food engineering processes could relieve the inherent problems of coordinating waste water management and protein production.The fish protein concentration process evaluated in this study is based on a recently developed food engineering process. This process was investigated because of its low cost and the functional properties of the final product.The literature investigation indicates microbiological agents and microbial toxins of public health concern will be destroyed during the fish protein concentration process investigated and prevented from forming in the final product. Laboratory investigations undertaken in this research document that the heavy metals cadmium, chromium, copper, lead and zinc concentrated in the final product on the average 15% or less than the maximum concentration that could have occurred (maximum concentration is the initial burden of a metal multiplied by the factor by which the raw tissue is concentrated). Information available suggests that the method of fish protein concentration investigated in this study concentrates the heavy metals less than similar processes reported previously.It is concluded that if the final fish protein concentrate is used as a supplemental protein, fish from waste waters can be used as the raw product in the process. Ideally, waste waters low in or devoid of industrial pollutatants should be chosen for fish culture.

ISSN:0748-3260    

DOI:10.1111/j.1749-7345.1979.tb00081.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTA series of experiments was conducted with American lobsters (Homarus americanus) and European lobsters (Homarus gammarus) to develop methods to reduce cannibalism among communally‐reared juveniles. The primary factors studied were substrate type, stocking density and photoperiod. Other conditions investigated were the effects of different water Temperatures, food type, segregating large individuals and claw immobilization. Preliminary studies also were conducted on the effects of shelter density, feeding level and tank area. These studies showed that by the use of vertical substrates, segregating techniques and immobilization of claws, carrying capacity can be increased considerabl

ISSN:0748-3260    

DOI:10.1111/j.1749-7345.1979.tb00082.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTFor over two years, ozone pilot plant studies have been conducted examining the efficacy of disinfecting makeup water entering the Dworshak National Fish Hatchery at Orofino, Idaho. The major pilot plant equipment consisted of a 1.12 kg/day Union Carbide Ozone Generator and contacting column.Plate counts for total bacteria were taken at various points in the pilot plant. Similar plate counts were taken from existing ultraviolet disinfection equipment. Also monitored were ozone residual levels entering and within the recycle system, ammonia, nitrate, nitrite, total organic nitrogen, suspended solids, turbidity and biochemical oxygen demand. Analysis of the plate counts shows ozone consistently provides more effective disinfection of the makeup water than the existing ultraviolet system. Nitrite levels after ozonation show a significant decrease, while nitrate levels increased. Ozone disinfection of recycle water was also satisfactorily demonstrated. Additionally, batch studies indicate ozone effectively destroyed algae.The pilot work established Dworshak ozone requirements to disinfect both makeup and recycle water. Experimental ozone demand, residual ozone removal rates, and ozone decay rates make it possible to design equipment and controls that will protect the fish from unsafe ozone concentrations. An ozone disinfection system preliminary design for a typical recycle fish hatchery is presented.

ISSN:0748-3260    

DOI:10.1111/j.1749-7345.1979.tb00083.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTElectrophoretic studies of gene‐enzyme variation in natural populations of the freshwater prawn (Macrobrachium rosenbergii) are undertaken to quantify the amount of racial divergence among geographically separated natural populations. A total of 440 individuals from 11 localities spread from Sri Lanka to New Guinea, Palau and the Hawaiian cultured stocks are analyzed for genetic variation in as many as 31 electrophoretically detectable proteins. Within‐population variability is relatively low: the average proportion of heterozygous loci in any given individual is 2.8% and the average proportion of polymorphic geneenzymes per population is 14%.Population differences are summarized by proportions of loci having no genotypes in common between populations (“% diagnostic loci”). Prawn populations from Australia, New Guinea, the Philippines, and Palau are well differentiated from the rest, with genetically fixed enzyme differences at over 20% of the gene‐enzyme systems. That this major discontinuity in the gene pool ofM. rosenbergiicorresponds to the well recognizedzoogeographicboundary known as Wallace' Line suggests that insular distribution has contributed to genetic divergence.One or 2 fixed or nearly fixed differences were also found among populations within the 2 major races east and west of Wallace' Line. These results support the hypothesis that this species has undergone substantial racial divergence over its range and that natural populations represent a tremendously diverse genetic resource forfreshwaterprawn aq

ISSN:0748-3260    

DOI:10.1111/j.1749-7345.1979.tb00084.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

ABSTRACTSeveral genetic stocks ofMacrobrachium rosenbergiiwere examined with respect to their physiological responses to different laboratory culture environments as juveniles and their development rates as larvae. Results indicate that physiological genetic differences exist between these genotypes and that these differences may be important for genetic improvement. Early growth rates for Thai, Sarawak, and Australian stocks were compared to those for the Anuenue stock (originally brought from Malaysia) at 19, 23, and 29°C. Growth at 19°C was very poor for all genotypes. At 23 and 29°C the Anuenue strain grew faster than the Thai and Australian strains and about equal to the Sarawak strain.Growth of Anuenue, Australian, Thai and Sarawak strains at 0, 5, and 10 ppt salinities was also compared. The Anuenue and Thai strains grew as well at 5 ppt as in freshwater while 10 ppt significantly depressed growth. In the Australian and Sarawak groups growth was depressed in both 5 and 10 ppt treatments.Temperature tolerance was found to increase with age for all strains although the Anuenue strain appeared to be the most tolerant to low temperatures. The prawns were tested just after metamorphosis at two weeks post‐metamorphosis and one month post‐metamorphosis.Tolerance to high pH was tested for the Anuenue and found to increase with age. Mortality at a pH of 9.5 at 29°C went from 80% for newly metamorphosed juveniles to 43% for two‐week‐old animals and 50% for one‐month‐old animals.Among the “pure” strains only the Australian strain showed significantly faster development times in replicated trials. The first Australian postlarvae appeared after an average of 15.5 days and 95% metamorphosed after 20.5 days compared to 24 and 32 days for the Anuenue strain. In unreplicated trials involving hybrids between Anuenue stocks and over two dozen other stocks only the Australian‐Anuenue hybrid showed faster larval development times with time to 95% settling at 35 days compared to 47 days for

ISSN:0748-3260    

DOI:10.1111/j.1749-7345.1979.tb00085.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

ISSN:0748-3260    

DOI:10.1111/j.1749-7345.1979.tb00086.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY