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The population dynamics of Metapenaeus ensis (Penaeidae) and Exopalaemon styliferus (Palaemonidae) in a traditional tidal shrimppond at the Mai Po Marshes Nature Reserve, Hong KongLeung, Siu-fai., 梁肇輝. January 1991 (has links)
published_or_final_version / Zoology / Doctoral / Doctor of Philosophy
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Mating behaviour, epibiotic growth, and the effect of salinity on grooming activity in the hermaphroditic shrimp Lysmata wurdemanniGiri, Tuhin 30 September 2004 (has links)
Many species of caridean shrimp are protandrous hermaphrodites, maturing initially as males but developing into females as they age and grow. A unique sexual system was recently discovered in the peppermint shrimp, Lysmata wurdemanni. In this species, individuals are initially male, but become simultaneous functional hermaphrodites over time. As in most caridean shrimp, L. wurdemanni can mate as a male during the intermoult period, but can reproduce through female function for only a short period after moulting. Ecdysis does not occur en masse in this species, and thus the operational sex ratio found in populations of L. wurdemanni is extremely male-biased. Sexual selection theory suggests that these conditions will result in increased competition for access to mates. Evolutionary pressures should therefore have selected for mechanisms that permit individuals to quickly identify and locate potential mating partners.
L. wurdemanni were exposed to chemical stimuli collected from recently moulted conspecifics of varying reproductive condition. Test animals were able to distinguish among the different conditions, and physically manipulated only the plastic nozzle used to pump solutions collected from shrimp with ovaries filled with vitellogenic oocytes. It was subsequently hypothesized that methyl farnesoate, a hormone associated with ovarian maturation in crustaceans, might be a key component of sex pheromones used by L. wurdemanni. However, a series of methyl farnesoate concentrations did not elicit responses, indicating this species does not use this hormone alone when determining reproductive condition.
Reproductive behaviour in L. wurdemanni was observed to differ both before and after copulation, as well as with increasing population density. Intermoult individuals were more likely to approach, follow and remain in the vicinity of a near-moult shrimp before mating could occur, and under high density conditions. The near-moult shrimp approached conspecifics only under low density conditions, and performed rapid escape behaviours only after copulation had occurred.
The unusual occurrence of epibiota upon L. wurdemanni was described, and the location, size and age of barnacles quantified. The effect of salinity upon grooming activities was tested. Results indicated that carapace grooming was depressed at low salinities, and could account for the considerable epibiota found in this region.
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Role of marine nitrifying bacteria in a closed system with Penaeus monodon.Pillay, Balakrishna. 21 October 2013 (has links)
In recent years there has been widespread interest in rearing aquatic
organisms of nutritional and commercial value (Calaprice, 1976). The
most hopeful prospect for marine prawn culture in the United Kingdom
(Wickins, 1976), the Americas (Hanson & Goodwin, 1977) and South
Africa probably lies in intensive culture under controlled conditions.
A closed system approach, in which a captive body of water is circulated,
provides the scope for water quality management which results ~n
maximum water utilization and minimal discharge. On the other hand,
direct utilization of sea-water in open systems presents problems for
aquaculture since this water is subjected to diurnal and seasonal fluctuations
in temperature, salinity and turbidity, as well as contamination
from industrial, agricultural and maritime sources. Furthermore,
large mariculture farms release enormous amounts of organic wastes which
result in eutrophication and could lead to environmental deterioration
of coastal waters (Gerhardt, 1978).
It is well established that circulated sea-water develops an unusual
~on~c composition as a result of the metabolic activity of the prawns
and of the nitrifying bacteria in the biological filter. The changes
include elevated levels of ammonia, nitrite and nitrate and reduced pH.
The presence of even sublethal levels of these nitrogenous compounds ~n
closed systems have been found to affect growth of penaeid spec~es
(Wickins, 1976). Ammonia and nitrite, which rapidly accumulate in the
water, are usually maintained at nontoxic levels by nitrification in
the biological filters (Spotte, 1974; Johnson & Sieburth, 1974). The
chemolithotrophic bacteria responsible for nitrification are presently
classified by their · cellular morphology and by the oxidation of either
ammonia and nitrite (Watson, 1974). The predominant ammonia- and
nitrite-oxidizing bacteria isolated from natural environments are
Nitrosomonas europaea and Nitrobacter winogradskyi, respectively (Watson
et aZ., 1981). Direct observation of nitrifying bacteria in natural
environments, however, has been limited to studies involving light
microscopy with immunofluorescent techniques (Fliermans et aZ., 1974;
Fliermans & Schmidt, 1975).
The electron microscopic observation of nitrifying bacteria ~sdifficult
in natural microcosms with low levels of nitrification and with the
presence of sunlight and anaerobic conditions conducive to the enrichment
of other bacteria with a similar ultrastructure. However, in
closed systems with extremely active nitrification but poor light conditions,
the occurrence of morphologically similar forms in numbers
that could be easily detected by electron microscopy is unlikely
(Johnsort & Sieburth, 1976). Furthermore, the cyst-like colonies of the
nitrifiers are unique and are not found with the methane-oxidizing
bacteria with a similar ultrastructure (Davies & Whittenbury, 1970;
Smith & Ribbons, 1970), whereas the thick cell wall of the cyanobacteria
(Carr & Whitton, 1973) and the distinctive cell morphologies of the
purple sulphur and purple nonsulphur bacteria (Pfennig, 1967) separate
them from the nitrifiers. Therefore, closed systems with active nitrification
provide the ideal environment to study the activities of nitrifiers
in conjunction with their relative abundance, nature and diversity.
In spite of the opportunity offered by closed systems, previous studies
(Kawai et aZ., 1965; Wickins, 1976; Gerhardt, 1978; Mevel & Chamroux,
1981) on nitrification have been primarily indirect observations on
rates of ammonia and nitrite oxidation to nitrate (Johnson & Sieburth,
1976). Studies on the enumeration and identification of nitrifiers ~n
closed systems have been seriously neglected. Kawai et aZ. (1964)
included the enumeration of nitrifiers in their study on nitrification
while,in a qualitative study, an attempt to identify the in situ nitrifiers
1n closed systems (Johnson & Sieburth, 1976) was not very successful.
This study was undertaken to investigate the three basic aspects of
nitrification necessary for the understanding of such a process in closed
systems, viz., the oxidation of ammonia and nitrite to nitrate, and the
enumeration and identification of the nitrifying bacteria. Prior to
determining the concentrations of the nitrogenous compounds in the
culture water, various methods were evaluated for their accuracy and
reproducibility with both sea-water and culture water samples. This
approach is necessary in order to gauge the accuracy of results obtained
by such methods. Enumeration of nitrifying bacteria was preceded by an
investigation on the effect of incubation time on the maximum most
probable number , estimate. Such an investigation was necessary
because of the inconsistent approach to the enumeration of nitrifiers in
previous studies (Wilson, 1927; Walker et al., 1937; Lewis & Pramer,
1958; Molina & Rovira, 1964; Meiklejohn, 1965; Smith et al., 1968).
Incubation periods appear to have been chosen arbitrarily in previous
investigations. Identifi~ation of nitrifying bacteria necessitates the
isolation and purification of these organisms. Isolation of nitrifiers
1S a difficult and time-consuming task (Watson et al., 1981) and could
be the main reason for not being included in previous studies on nitrification.
Since the success of this study depended upon the isolation
and purification of these chemolithotrophs, this aspect is de~lt with
in detail.
The changes most likely to be associated with nitrification in a closed
system were also monitored 1n the culture water. These included pH,
dissolved oxygen and biochemical oxygen demand. Apart from a biological
sand filter, no other form of culture water treatment was effected
during the investigation. The effect of growing the "sugpo" or jumbo
tiger prawn, Penaeus monodon (Kinne, 1977) for 22 weeks in a captive
body of sea-water was evaluated by comparing the survival and wet mass
with those reported by other workers.
This study differs greatly from previous reports on nitrification in
closed systems because both the "causes" and "symptoms" of this important
detoxifying process are investigated. It is intended that the
findings of such a study would aid culturists in exploiting the nitrifying
potential of closed systems to its utmost. / Thesis (M.Sc.)-University of Durban-Westville, 1984.
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Extraction and identification of Maillard reaction precursors from shrimp and GCMS investigation of related Maillard model systemsMandeville, Sylvain January 1993 (has links)
Proximate analysis of the commercial shrimp meat waste samples indicated the presence of 94.6% protein and 4.2% fat on a dry basis. The HPLC analysis revealed the presence of 17 amino acids (proline most abundant) and 7 sugars (ribose being the most abundant). The changes in the concentration of the amino acids and sugars after heat treatment, are explained based on their interaction through the Maillard reaction and by the thermal hydrolysis of proteins and polysaccharides present in tissue. Carotenoid pigments ($ beta$-carotene, canthaxanthin, astacene, and astaxanthin monopalmitate) were extracted and separated by thick layer chromatography. Their structures were identified tentatively by thick layer chromatography (TLC) and subsequently confirmed by Fourier transformed infrared (FT-IR) spectroscopy. Lipids were separated and categorized into glycerides, sterols, and phospholipids by thin layer chromatography while flavor-active components were extracted by different organic solvents into acidic, basic, and neutral fractions and their sensory properties determined. The flavor profile of the raw and cooked shrimp meat waste revealed the presence of 59 compounds in raw shrimp compared to 44 in cooked. The components identified were of different functional groups, including fatty acid esters, long chain alcohols, aldehydes, ketanes and hydrocarbons. Many fractions provided desirable aroma (nutty, fruity, floral, green woody, meaty) indicating the presence of important flavor compounds in the commercial shrimp waste. / Model studies were carried out under different experimental conditions (water content, pH), to observe the influence of these parameters on the formation of Maillard reaction products. Furthermore, a comparative study between direct injection of the aqueous solutions and its organic extracts was conducted. The direct injection of aqueous solutions revealed the presence of many water soluble components that were not detected by organic solvent extraction such as droserone and 3,9-diazatricyclo$ lbrack7.3.0.0 sp{*}.3 sp{*}.7 sp{ *} rbrack$-dodecan-2,8-dione while maltoxazine and acetanilide are example of compounds identified only in the dichloromethane extracts. Results also demonstrated that monosaccharides affected the yield of the compounds produced whereas the amino acids influenced the sensory properties of these models. Fructose and ribose were found to be the most reactive sugars in their respective categories. Thiazoles were found to be more water soluble whereas $ beta$-carbolines were more abundant in the organic extracts. The influence of water content was investigated in model systems containing fructose or glucose. It was found that water free systems decreased the yield of pyrazines and thiazoles while the formation of pyrrole and pyridine derivatives increased under dry heating conditions. The formation of Maillard reaction products were studied under different pH conditions in order to assess the effect of pH on the formation of heterocyclic compounds. Pyrazine and furan derivatives were the most affected by pH and alanine was found to be a better nitrogen source than lysine in the formation of pyrazines under different pH conditions. Finally, based on energy minimization studies using MM2 force field, a plausible mechanism was proposed for the formation of maltol in Maillard model systems.
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The digestion of microbial and detrital resources by an omnivorous shrimp, Penaeus vannamei BooneBurgett, Jeff M January 1994 (has links)
Thesis (Ph. D.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 102-123). / Microfiche. / xiii, 123 leaves, bound ill. (some col.) 29 cm
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Investigations of water supply and water quality issues related to inland shrimp farming in western AlabamaBoyd, Christopher Andrew, Rouse, David B. January 2006 (has links) (PDF)
Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.
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Optimization of dietary nutrient inputs for Pacific white shrimp Litopenaeus vannameiVenero, Jesus A., Davis, D. Allen January 2006 (has links) (PDF)
Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.
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Physiological and nutritional requirements for the culture of the Pacific white shrimp, Litopenaeus vannamei, in low salinity watersRoy, Luke A., Davis, D. Allen. January 2006 (has links) (PDF)
Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.
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Food and feeding patterns of the southern brown shrimp Penaeus subtilis Pérez-Farfante, 1967 (Crustacea, Penaeidae) /Nunes, Alberto Jorge Pinto, January 1999 (has links)
Thesis (Ph.D.)--Memorial University of Newfoundland, 1999. / Accompanying floppy disk consists of Appendix H: Presentation of models in the STELLA II environment. Bibliography: leaves 217-249.
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Fate and transformation of dietary nitrogen in penaeid prawn aquaculture ponds /Burford, Michele. January 2000 (has links) (PDF)
Thesis (Ph.D.) - University of Queensland, 2001. / Includes bibliography.
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