Thesis (M.S.)--University of North Carolina Wilmington, 2009. / Title from PDF title page (February 21, 2010) Includes bibliographical references (p. 51-60)

The combined effects of food availability and predation risk on fish foraging behavior have been investigated via both laboratory and field experiments, primarily in temperate, freshwater systems and during daylight hours. In contrast, relatively little attention has been directed towards fish foraging decisions along subtropical shorelines, which serve as nursery grounds for a variety of economically important fishes, as well as at night, when many species emerge from refuges to feed. The mangrove-seagrass ecotone and adjacent seagrass beds constitute nocturnal feeding grounds for fish secondary-tertiary consumers. In subtropical Biscayne Bay, Florida (USA), I investigated the influences of food and risk on nocturnal seagrass use by gray snapper (Lutjanus griseus), bluestriped grunt (Haemulon sciurus), great barracuda (Sphyraena barracuda), and seabream (Archosargus rhomboidalis) along a distance gradient, spanning from the mangrove fringe to 120 m from shore. This was accomplished by conducting a series of integrated field and laboratory studies, including: (1) nocturnal seine sampling to determine fish abundance patterns in relation to the mangrove-seagrass interface; (2) fish stomach content analysis to reveal feeding habits and trophic relationships; and (3) diel field tethering experiments to explore nearshore gradients in predation pressure. With these data I tested a priori predictions of fish distributions relative to food and predation risk that were generated from foraging theory: (1) fishes will be distributed across the distance gradient in proportion to their food supply (i.e., ideal free distribution, IFD); or (2) fishes will avoid high risk areas such that their abundances will be lower than predicted by food resources in high-risk habitats (i.e., food-risk trade-off). Results revealed that fish assemblage composition differed by season and distance from shore, with the zone nearest the mangroves generally harboring the lowest densities of late-stage juvenile fishes. Stomach content analysis demonstrated that gray snapper fed on a variety of small fishes and crustaceans, while bluestriped grunt fed primarily on caridean shrimp. Seabream fed almost exclusively on vegetation and great barracuda was almost entirely piscivorous; however, seasonal shifts in diet and feeding habits were evident. Seasonal shifts in major food resource use generally did not correspond with changes in relative abundance of food supply. Seasonal trophic niche breadth differences were evident for gray snapper, great barracuda and bluestriped grunt, while niche breadth was equivalent between seasons for seabream. Based on seasonal food supply in the environment, niche breadth values did not match basic foraging theory predictions, which state niche breadth should expand as preferred food resources become scarce. Tethering experiments indicated that predation rates were highest nearest the mangrove edge and decreased with increasing distance from shore. Moreover, predation pressure at night was nearly twice as high compared to the day. Testing these data against my predictions from foraging theory, I found that none of the fishes examined (gray snapper, seabream and bluestriped grunt) were distributed according to IFD. Seabream and gray snapper avoided foraging close to the mangrove-edge, where their food was most abundant, but risk was highest. Bluestriped grunt appeared to forage randomly across the distance gradient despite spatial variation in food and predation risk. Overall, results suggest that: (1) spatial patterns of utilization of seagrass habitat adjacent to the mangrove-seagrass ecotone differs by species, life-stage and season; (2) Seasonal shifts in diet were not correlated with changes in relative abundance of food supply; (3) trophic niche breadth of late juveniles did not expand with declines in their food resources; (4) the mangrove-seagrass ecotone appears to serve as a hunting corridor for predators targeting juvenile fishes moving about the mangroves; and (5) two of the three species examined appeared to give up food in return for safety by avoiding foraging near the mangroves, despite high food availability.

Inhibin and activin are disulphide-linked dimeric proteins that belong to the transforming growth factor superfamily. Inhibin and activin are identified that they have ability to modulate the secretion of follicle-stimulating hormone, FSH, from pituitary. Activin can stimulate FSH secretion, on the other hand, inhibin can inhibit FSH production. According to many researches, inhibin and activin play an important roles in regulation of reproduction. Black porgy (Acanthopagrus schlegeli) is belong to protandry.that has a complex regulation in sex differentiation and development. The male differentiation in black porgy started at fourth month, and the testis become mature when the spawing season coming.in the first two year in black porgy, they are differentiate to functional males, and some of them will change to females in the third year. The objectives were to study the possible roles of inhibin¡Bactivin subunits and their receptors in sex differentiation and sex change in black porgy. The gene expression of activin system increase during the period of ovarian development. The expression of activin receptors in ovarian tissue are higher than in testis tissue in the testis-excision experiment. The expression of inhbab ¡Bacvr1and acvr2b after testis-excision are higher than in control in black porgy forebrain. The expression of inhbaa increase at four to five months after hatching in 0+-yr old black porgy, and the expression of inhbb and receptors decrease at the same time. According to these results, activin system may involve in the ovarian development and mature, and play important roles in testis differentiation and development in black porgy. Furthermore, activin system have sex dimorphisms in forebrain in black porgy.

The objectives of this study were to investigate the characteristics and mechanism of gonad maturation including identified maturation inducing steroids and its physiological role in the final oocyte maturation (FOM) in yellowfin porgy. yellowfin porgy, Acanthopagrus latus are functional male for the first year of life but begin to change sex during the second year. Only 30~50% of cultured yellowfin porgy are change into females in 2-year-old, while 80% fish become females at 3-year-old. Vitellogenesis were observe between August and November and have the highest gonadosomatic index (GSI %) at 6.88 % and 14.35 % in 2 and 3-year-old female yellowfin porgy respectively. Highest serum levels of T occurred simultaneously during spawning season in one and two years of age in functional male, while highest level concentration E2 were observed at the same time in two and three years old female fish. GSI increased 1.5-fold during FOM and reach 2-fold at germinal vesicle breakdown stage (GVBD). Oogenesis in 3-year-old female yellowfin porgy was divided into three stages¡F(1) previtellogenic stage from February to July with the primary oocytes¡F(2) vitellogenic stage from August to October and with full growth oocyte of diameter at 400

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Joseph Travis, Florida State University, College of Arts and Sciences, Dept. of Biological Science. Title and description from dissertation home page (viewed June 13, 2006). Document formatted into pages; contains xvi, 160 pages. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 2003. / Title from PDF title page (viewed Apr. 3, 2005). Vita. Includes bibliographical references.

The present study used Escherichia coli¡]BL21¡^that contained pET-23a-bpGH plasmids, to express black porgy growth hormone ¡]bpGH¡^. The bpGH was refolded at pH 11.3 in the presence of catalytic amounts of cysteine and purified by ion exchanger chromatography and gel filtration chromatography. The purified bpGH is a monomer and has a molecular weight of 22 kDa. Using the bpGH, the effects of the growth hormone on growth, essential amino acid deposition and nonspecific immunity in black porgy were studied. The experiment was a 4*3 ¡]diet*GH¡^ factorial design. Four experimental diets were formulated in that fish meal was replaced by the mixture of soya protein and gelatin so that fish meal / soya mixture = 100 / 0, 75 / 25, 50 / 50 and 25 / 75, respectively. GH treatments included non-injection, once per 3 days and once per 12 days. GH was injected intramuscularly at a dosage of 0.05 µg / g wet body weight. The growth trial lasted for 72 days. The results showed that GH administration significantly enhanced weight gain, feed efficiency, protein efficiency ratio and muscle methionine concentration of the fish. GH injection improved the growth performance of the fish fed low protein quality diets to a level equals to the groups fed high protein quality diets. These results indicate that GH injections enhanced the perferential absorption and deposition of the first limiting amino acid methionine from the diets. In addition, GH administration enhanced alternative complement activity and increased serum lysozyme concentration, implicating the enhancement of the immunity.

Red porgy <i>Pagrus pagrus</i> is a reef fish important to both recreational and commercial fisheries off the coast of the southeastern United States. Stock assessments performed on this species since 1985 have shown a population in decline. As a result, a number of management actions were put in place, including a harvest moratorium in 1999. Stock assessments for many marine species, including red porgy, rely on a combination of fishery-dependent and fishery-independent data. When a moratorium is in place, the flow of fishery-dependent data is interrupted, making assessments more reliant on fishery-independent information. To investigate how loss of fishery-dependent data, as during a moratorium, would affect stock assessment results for red porgy, I conducted model simulations to represent moratoria of various durations. The most recent red porgy stock assessment model developed during a 2002 workshop was used as a tool in these simulations. I found that biological reference points, such as biomass and fishing mortality, and population projections were more variable for longer simulated moratoria. When fishery-dependent data were removed, minor fluctuations in length and age frequencies resulted in larger fluctuations in estimates of biological reference points. The simulated moratoria also resulted in a slight bias toward over-estimating stock productivity. Similar simulations and analyses were conducted to determine the effects of reducing fishery-independent data from the Marine Resources Monitoring, Assessment, and Prediction (MARMAP) program. Length and age data of reduced MARMAP sample sizes were bootstrapped from original data, and used as input for the stock assessment model. Biological reference points and population projections were more variable for small MARMAP sample sizes, due to the incomplete representation of the length and age frequencies of the population. Reduced sample sizes also showed a slight bias toward predicting a more productive population. These types of simulations emphasize the benefits of investigating potential effects of data reduction on assessment results prior to implementing management strategies, such as a moratorium or sampling change, that cause data loss. Although decreasing red porgy data resulted in slight changes in assessment results, there are more data available for this species than other species in the snapper-grouper complex. For these lesser-studied species, reducing data could dramatically affect assessment capabilities. To investigate this, I compiled available data for these species and identified the stock assessment method used. I then predicted assessment capabilities for each species under a moratorium and if the MARMAP survey was eliminated. A moratorium could reduce assessment capabilities for 37 of the 73 species, and 63 species would require management based on key species. Removing MARMAP data would reduce assessment capabilities of eight species, many of which are economically important. There was an overwhelming need for a reliable catch-per-effort index, information that could improve assessment capabilities of 67 species. This index could be obtained by expanding the MARMAP survey, from a fishery observer program, or from commercial logbooks. By linking the red porgy stock assessment, an evaluation of sampling regimes and data loss during a moratorium, and the expansion of this stock assessment strategy to multiple species, managers will ultimately benefit from increased ability to manage stocks experiencing varying regulations and data availability. / Master of Science

[pt] Esta tese é um trabalho teórico-prático sobre a tradução vocal para o português dos números musicais da ópera Porgy and Bess, de George Gershwin, sobre libreto de DuBose Heyward e letras de DuBose e Ira Gershwin. Aqui a tradução vocal é entendida como aquela destinada ao canto. Portanto, as traduções estão organizadas e editadas em partituras de redução da ópera, isto é, vocal(ais) e piano. Somam-se a esse núcleo da tese dois capítulos. Um teórico, em que são discutidas as principais tendências do recente campo de estudos sobre a tradução de ópera, e outro de comentários sobre a tradução realizada. / [en] This thesis is a theoretical-practical work on the vocal translation into Portuguese of the musical numbers from George Gershwin s opera Porgy and Bess, with libretto by DuBose Heyward and lyrics by DuBose and Ira Gershwin. Here vocal translation is understood as that intended for singing. Therefore, the translations are arranged and edited into reduction scores of the opera, that is, vocal(ls) and piano. Added to this core of the thesis are two chapters. One is theoretical, in which the main trends of the recent field of studies on opera translation are discussed, and the other is a commentary on the translation performed.

This is a detailed study of Afro-American folklore and its presence in George Gershwin' s Porgy And Bess. The study concerns itself with the historical, spiritual, analytical and sociological aspects of the opera. Negro traits are explored from their environments to their lifestyle, from their folklore to their underlying values and traditions. The first chapter is entitled 'TOWARDS A DEFINITION OF FOLK'. Before even discussing Afro-American folklore, the meaning of 'folk' or 'folklore' needs to be established. What is most important about 'folk music' is that it is learnt through oral tradition. Among its many functions are accompanying activities, narrations or dance music. There are certain musical styles which are characteristic of folk music; this comprises the text, melody, harmony, form or singing style. The most common folk instruments used are shared with the world's simplest tribal cultures. It is history that makes folk music. A community which behaves in a certain way today, makes history tomorrow, and this is 'folk'. Chapter Two entitled 'AFRO-AMERICAN FOLKLORE', discusses Black music that developed in the U.S.A. after the Africans were imported to America as slaves. They created their own music, which included work songs, field hollers, spirituals and the blues. Their music had certain characteristics where melody, harmony, singing styles, group singing, handclapping and percussive effects were concerned. The third chapter entitIed 'THE PRESENCE OF AFRO-AMERICAN FOLKLORE IN PORGY AND BESS', is an analysis of the music. The folk elements of the opera are exposed and then aligned to the Negro lifestyle discussed in the previous chapter. Chapter Four entitled 'A SOCIOLOGICAL APPROACH', discusses white 'folk' teaching Black 'folk' how to do what they do naturally. The views of the performers, the criticism of the press and the reaction of the audience are also included. The appendices comprise two interviews; one with the original 'Porgy' and the second with the original choral director of Porgy And Bess, who claims to have translated the dialect of standard English into a negro style flavour. / Thesis (M.Mus.)-University of Natal, Durban, 1993.