• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 23
  • 20
  • 8
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 76
  • 18
  • 12
  • 11
  • 11
  • 11
  • 10
  • 9
  • 8
  • 8
  • 7
  • 7
  • 7
  • 6
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Indicadores de sustentabilidade na larvicultura de camarão-da-amazônia, Macrobrachium amazonicum / Sustainability indicators of the Amazon River Prawn hatchery

Frota Filho, Josué Fernandes 19 April 2018 (has links)
Submitted by JOSUÉ FERNANDES FROTA FILHO (frotafilho.jf@outlook.com) on 2018-04-24T17:00:58Z No. of bitstreams: 1 Josue_Dissertação_24_04_FINAL.pdf: 705810 bytes, checksum: c7f70d2764da25e302dc2b38af6c84bd (MD5) / Rejected by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br), reason: Solicitamos que realize correções na submissão seguindo as orientações abaixo: O arquivo pdf submetido ao repositório deve conter a ficha catalográfica e o certificado de aprovação (documentos obrigatórios). Favor inserir no arquivo pdf a ficha catalográfica e o certificado de aprovação (tudo em um arquivo só). Agradecemos a compreensão. on 2018-04-25T12:56:05Z (GMT) / Submitted by JOSUÉ FERNANDES FROTA FILHO (frotafilho.jf@outlook.com) on 2018-04-26T11:48:21Z No. of bitstreams: 1 Josue_Dissertação_24_04_FINAL corrigido.pdf: 927542 bytes, checksum: a658dd423a96120871bc91bfa99cbc9b (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-04-26T12:10:28Z (GMT) No. of bitstreams: 1 fotafilho_jf_me_jabo.pdf: 927542 bytes, checksum: a658dd423a96120871bc91bfa99cbc9b (MD5) / Made available in DSpace on 2018-04-26T12:10:28Z (GMT). No. of bitstreams: 1 fotafilho_jf_me_jabo.pdf: 927542 bytes, checksum: a658dd423a96120871bc91bfa99cbc9b (MD5) Previous issue date: 2018-04-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O crescimento acelerado da aquicultura vem sendo acompanhado pela crescente preocupação em se garantir a sustentabilidade das atividades aquícolas. A sustentabilidade neste trabalho é baseada principalmente em duas dimensões: ambiental, e econômica. O presente trabalho teve como objetivo avaliar a sustentabilidade ambiental e a viabilidade econômica em pequena escala de produção de pós-larvas do camarão de água doce da espécie Macrobrachium amazonicum, por meio de um conjunto indicadores de sustentabilidade. Foram considerados os ciclos de produção durante um ano de cultivo de pós-larvas do camarão-da-amazônia. A capacidade produtiva considerada foi de 290 milheiros de pós-larvas/mês. A sustentabilidade ambiental foi medida com base na utilização de recursos naturais, eficiência no uso destes recursos e poluição liberada ao ambiente pelo meio de cultivo. A sustentabilidade econômica foi medida com base nos aspectos sobre a eficiência no uso dos recursos financeiros e a capacidade de gerar recursos para reinvestimentos na atividade. Os resultados sugerem que há viabilidade econômica para o produtor que realiza larvicultura em sistemas de fundo de quintal (backyard hatchery). Além disso, os dados obtidos também mostraram que embora a larvicultura seja uma atividade bastante intensificada, há eficiência na utilização dos recursos naturais, sendo mais sustentável do que outras fases de produção, como o berçário e crescimento final da mesma espécie. Desse modo, o modelo utilizado é uma alternativa viável com sustentabilidade econômica e ambiental para produção de pós-larvas de M. amazonicum em sistemas familiares de produção. / The rapid growth of aquaculture has been accompanied by the increasing concern to ensure sustainability of aquatic activities. In this work, sustainability is based on environmental and economic dimensions. The objective of the study is to evaluate the environmental and economic sustainability of a small scale Macrobrachium amazonicum post-larvae production using a set of indicators for sustainability. Production cycles during one year of the Amazon Prawn hatchery was considered. The considered productive capacity was 290 thousand post larvae/month. Environmental sustainability measurements were based on the use of natural resources, efficiency in the use of resources and pollution released to environment from the production facility. Economic sustainability measurements were based on the aspects of efficiency in the use of financial resources and the capacity to generate resources for reinvestments in the activity. Results show that there is economic feasibility for the ‘backyard’ hatcheries system for freshwater prawn farmers. In addition, data indicate that in spite of hatchery being a highly intensified activity, there is efficiency in using natural resources, and it is more sustainable than other production phases, such as nursery and grow-out phase of the same species. To sum it up, the hatchery model studied is a feasible and sustainable alternative to produce M. amazonicum post-larvae with environmental and economic sustainability to be operated using either family labour production. / 88882.156917/2017-01
12

Nearshore restoration associated with large dam removal andI implications for ecosystem recovery and conservation of northeast Pacific fish: lessons learned from the Elwha dam removal

Shaffer, J. Anne 04 May 2017 (has links)
This dissertation addresses the relationship between large-scale dam removal and the nearshore ecosystem function for fish. The work is based on almost a decade’s worth of collaborative field work in the nearshore of the largest dam removal in the world recently completed on the Elwha River. The data analyzed span seven years prior to, during, and throughout the first year of each dam removal (January 2008 to November 2015). As of September 2015, approximately 2.6 million m3 of sediment material increased the area of the Elwha delta to over 150 ha. Long term study of fish in the estuary reveals fish community response to dam removal, and indicates likely interactions in the nearshore between hatchery and wild fish, including chum salmon critical to watershed recovery. Continued hatchery releases may therefore further challenge chum salmon recovery, and this interaction should be considered when planning for future watershed recovery. Community analysis revealed that, while species richness and taxonomic diversity do not appear to have a significant response to dam removal, functional diversity in the nearshore does respond significantly to dam removal. Three main shifts occurred in the nearshore: large scale and rapid creation of estuary habitats; delivery of large amounts of sediment to the delta/estuary in a short period of time, and; a shift in original habitats from tidally influenced to non-tidally influenced habitats resulted in changes in estuary function. Changes in functional diversity occur disproportionately in the new sites, which have more unstable, and so less resilient, communities. Functional diversity in the original estuary sites appears to be more resilient than in the newly created sites due to the large-scale environmental disruption that, ironically, created the new sites. However, the functional diversity at the original sites may be defined in part by management activities, including hatcheries that could mute/mask/inhibit other community responses. Further, functional diversity at the newly formed nearshore areas is predicted to stabilize as the habitats are vegetated and mature. Principal components analysis of Elwha fish community over the course of this study reveals that the fish communities of the Elwha are predictably grouped, indicating that while a few new species are observed, dam removal has not resulted in observable disruptions in fish community assemblages. And finally, nearshore habitats are critical for many forage fish species, and an emerging topic for large-scale dam removals. Forage fish spawning response to dam removal appears to be complex and may be related to multiple factors including high interannual variability in physical habitat conditions, geographic factors and complex life histories of forage fish. Habitat suitability for forage fish spawning should increase as restored ecosystem processes and newly created habitats mature and stabilize, indicating that time may be an important factor in nearshore restoration for forage fish spawning. It is therefore important to implement long-term monitoring and incorporate nearshore ecosystem process and function for multiple life history stages of nearshore species, including forage fish, into large-scale dam removal restoration and management planning. / Graduate / 2019-04-12
13

Subspecies Composition, Genetic Variation and Structure of Largemouth Bass in Puerto Rico Reservoirs

Peterson, Nick Ryan 11 December 2015 (has links)
Subspecies composition and genetic variation are important to the growth and survival of Largemouth Bass and information on these genetic characteristics is required for proper management of the species. In Puerto Rico, a genetic evaluation is needed to develop management plans for Puerto Rico reservoirs and maintain Florida Largemouth Bass at the Maricao Hatchery. Subspecies composition was characterized among reservoirs and the contemporary Maricao Hatchery broodstock in Puerto Rico, and metrics were compared between subspecies and hybrids among reservoir populations. Genetic variation and structure was determined and compared to Largemouth Bass populations in their native range. Florida subspecies were prevalent in all populations and non-introgressed subspecies seemed to be better adapted to the island than introgressed forms. Genetic diversity was lower in Puerto Rico populations and substantial genetic structure among populations was lacking. These results provide genetic information to guide future management and propagation of Largemouth Bass in Puerto Rico.
14

Evaluating the Feasibility of Rearing Juvenile Freshwater Mussels in a Flow-Through Pond System at White Sulphur Springs National Fish Hatchery

Mummert, Andrea Karina 11 January 2002 (has links)
A flow-through pond at White Sulphur Springs National Fish Hatchery was evaluated as culture environment for juvenile freshwater mussels of Villosa iris and Lampsilis fasciola. Survival did not differ significantly (p = 0.1910) over 93 d for V. iris cultured with silt (mean 49.8% ± SD 14.5) and without (mean 32.9% ± SD 11.7). Survival differed significantly (p <0.0001) between juveniles of V. iris (mean 49.8% ± SD 14.5 at age 93 d) and L. fasciola (mean 6.3% ± SD 4.5 at age 86 d). This may indicate that the pond failed to meet requirements of L. fasciola, or may have resulted from microhabitat variables. Growth did not differ significantly between species (p = 0.1315). Villosa iris reached a mean length of 1.81 mm ± SD 0.67, and L. fasciola 1.78 mm ± SD 0.78. Water quality parameters remained within suitable ranges, and planktonic algal densities were between 2850 - 6892 cells/mL. Survival of V. iris and growth of both species compares favorably to previous culture attempts. Juveniles of V. iris and L. fasciola were exposed to ammonium chloride solutions for 96 h in static renewal conditions at 12°C and 20°C. Calculating LC50 values with the Trimmed Spearman-Karber method, juveniles of L. fasciola (mean 96 h LC50 of 0.26 mg/L NH3-N) were significantly more tolerant of unionized ammonia than juveniles of V. iris (mean 96 h LC50 of 0.11 mg/L NH3-N). The only organisms with reported LC50 values lower than those seen for V. iris juveniles were Ceriodaphnia dubia and Hyella azteca. / Master of Science
15

Release of Juvenile Mussels into a Fish Hatchery Raceway: a Comparison of Techniques

Hanlon, Shane David 27 April 2000 (has links)
Recent efforts to restore depressed or extirpated populations of freshwater mussels have focused on artificial propagation as an effective and practical conservation strategy. Although artificially cultured juveniles have been produced and released to the wild, no study has investigated the best time of year or the best developmental stage to release these juveniles. Several experiments were conducted to gain knowledge of appropriate culture and release techniques. Juvenile wavyrayed lampmussels (<I>Lampsilis fasciola</I>) were artificially propagated in the laboratory and subsequently release into a fish hatchery raceway during June, September and March. Juveniles released in June experienced a gradual decline in survival rate, with 50% survival after 72 days and stable survival thereafter until 200 days. Juveniles released in September and March experienced high mortality within the first month, and were unsuccessful in surviving the cold water conditions typical of those seasons. Temperature was strongly associated with growth; thus, juveniles released in June exhibited considerably greater growth than those released in September and March. Survival was positively correlated with shell length in the first 32 days post-metamorphosis. Fall and spring survival values, shell length-frequency data, and a significant increase in overwinter mean shell length (p = 0.045) suggest that overwinter survival is size-dependent. Survival rates of juveniles released in June exceed those of previous culture studies reported in the literature. From these results, I suggest that the best time for release of propagated juvenile freshwater mussels should be at the beginning of the growing season in late spring, when water temperatures exceed 15 degrees C (plus/minus 1°C). Offspring of four, gravid female <I>L. fasciola</I> were tested to evaluate the extent of variability in growth and survival among brood stock. Comparison of growth and survival of progeny showed significantly lower performance of only one female (p < 0.05). Although results indicate variability in growth and survival among broods, it is not known whether heritabilities or physiological fitness caused this variability. Infested fish (IF), newly metamorphosed juveniles (NMJ) and juveniles cultured for 1 month (CJ) were released to a fish hatchery raceway in order to determine the most appropriate developmental stage to release juveniles. Significant differences were recorded among the three release methods, with CJ attaining the greatest growth (2.47 mm plus/minus 0.02), NMJ with the next best growth (1.86 mm plus/minus 0.02), and IF exhibiting the least growth (1.34 mm plus/minus 0.02) (p < 0.0001). Survival among release methods was not statistically different because of high variability within each release method. High mortality from predacious fish was presumably the cause of this variability. With minimal predation, L. fasciola experienced 82.2% (plus/minus 3.6) survival at 90 days. Survival of hatchery-reared juveniles was comparably higher than laboratory-reared juveniles, suggesting that culturing freshwater mussels in a hatchery raceway is a preferable alternative to laboratory culture. An experiment was conducted to compare growth of confined and unconfined juvenile L. fasciola released to a fish hatchery raceway. After 72 days, juveniles confined to small open dishes within the raceway (1.04 mm plus/minus 0.08) exhibited significantly less growth than juveniles released to the raceway that were not held in containers (2.15 mm plus/minus 0.07) (p < 0.0001). Results of additional comparisons with compiled growth data suggest that juvenile growth is retarded when cultured in small dishes. / Master of Science
16

Reproduction of the South African abalone, Haliotis midae

Visser-Roux, Adelle 12 1900 (has links)
Thesis (PhD (Genetics))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Currently, South African aquaculture is dominated by the cultivation of Haliotis midae, which is estimated as the most lucrative sector of the industry, with 934 t being export in 2008, totalling an income of ZAR 268 million (40 million USD) in 2008. This represents 81% of the total rand value of the aquaculture sector. Abalone was the highest aquaculture commodity exported during the last two years from South Africa, representing 24% of the total tonnage exported. Employment in the aquaculture sector increased by approximately 80% between 2005 and 2008, and was highest in the abalone sector where the number of people employed increased by 234%. Despite these high production rates, no hatchery procedures have been developed specifically for H. midae. Most procedures and protocols currently used in South African abalone hatcheries have been adopted from cultivation methods used for foreign species. Although certain aspects of reproduction are universally conserved between abalones, it is important to consider the physiology and the origin of the species studied. To date, no scientific research has been conducted on the reproduction of H. midae, except for a few studies in the early 1990s, which focused on the basic reproduction of this species. No further studies have been done on H. midae reproduction under intensive culture. Currently, hatch-out rates obtained by most abalone farms in South Africa averages 80%, with a 50% settlement rate, and a final hatchery output of only 30%. This study reports on various aspects of H. midae reproduction that can influence its commercial culture. A detailed histological characterisation of gametogenesis was developed. Findings indicated that cultured H. midae reaches 50% sexual maturity at a shell width of between 25 mm and 30 mm. During fertilisation trials, a sperm concentration of 50 000 sperm mL-1 and egg concentrations lower than 50 eggs mL-1 produced the highest hatch-out rates. Whilst fertilisation volume did not influence fertilisation success, fertilisation potential of the eggs did decrease with time. Eggs older than 100 minutes showed a lower fertilisation potential than eggs fertilised earlier. A larval stress test was developed to evaluate larval resistance against chemical stress. It was determined that 50% of resultant larvae would exhibit morphological abnormalities after fertilised eggs were incubated in 0.7% dimethyl sulfoxide (Me2SO) for a 24 hour period. If larvae exhibited fewer abnormalities at this concentration, it could be deduced that the larvae had a high resistance to the negative effect of the toxicant, and could thus be seen as good quality larvae. When evaluating hybridisation potential between H. midae and H. spadicea, it was found that it was possible to fertilise spawned H. midae eggs with biopsied H. spadicea sperm. By incorporating the results obtained from the present study into current hatchery systems on South African abalone farms, higher hatchery yield could be achieved, which in turn would lead to an increase in commercial revenue. / AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse akwakultuur sektor word tans oorheers deur die produksie van Haliotis midae, en word gereken as die mees winsgewendste bedryf in die industrie, met 934 t uitgevoer in 2008, na-raming „n inkomste van ZAR 268 miljoen (40 miljoen Amerikaanse doller). Dit verteenwoordig sowat 81% van die totale rand waarde in die akwakultuur bedryf. Perlemoen was ook die grootste uitvoer kommoditeit gedurende die laaste twee jaar, en het tot sowat 24% van die totale uitvoer vanuit akwakultuur bygedra. Werksgeleenthede in die akwakultuur sektor het tussen 2005 en 2008 met ongeveer 80% gegroei, waarvan die hoogste groeisyfer in die perlemoen bedryf was, waar die aantal werknemers met 234% toegeneem het. Ten spyte van hierdie hoë produksie omset, is daar tans geen protokolle wat spesifiek vir die produksie van H. midae ontwerp is nie. Meeste van die tegnieke wat huidiglik gebruik word op Suid-Afrikaanse plase, is gebaseer op, en aangepas vanaf metodes daargestel in die internasionale bedryf vir uitheemse spesies. Alhoewel sekere aspekte van reproduksie tussen perlemoen spesies verband hou, is dit belangrik om die fisiologie en oorsprong van die spesie van belang, in ag te neem. Wetenskaplike navorsing gedoen op die reproduksie van H. midae is beperk tot studies in die vroeë 1990s, wat die basiese beginsels van die spesie se reproduksie ondersoek het. Daar is geen verdere studies op die reproduksie van H. midae, veral onder intensiewe teel toestande, gedoen nie. Tans toon die meeste perlemoen plase in Suid-Afrika „n produksie persentasie van ongeveer 80% larwes vanaf bevrugting, met „n afname na 50% met vestiging en „n gevolglike uitset van slegs 30%. Hierdie studie doen verslag oor verskeie reproduksie aspekte van H. midae wat die teel doeltreffendheid van perlemoen op kommersiële plase kan beïnvloed. „n Gedetaileerde histologiese karakterisering van gametogenese is ontwikkel. Daar is gevind dat geteelde perlemoen 50% geslagsrypheid bereik met „n skulp wydte van tussen 25 mm en 30 mm. Tydens bevrugting eksperimente is bepaal dat 50 000 sperm mL-1 en „n eier konsentrasie van laer as 50 eiers mL-1, die optimale gameet konsentrasies is vir effektiewe bevrugting. Alhoewel die volume water waarin bevrugting plaasvind nie „n invloed getoon het op bevrugtingsukses nie, is daar wel gevind dat die eiers se potensiaal om bevrug te word, afneem met verloop van tyd. Eiers ouer as 100 minute het „n verlaagde bevrugtingspotentiaal getoon teenoor eiers wat vroeër bevrug is. „n Larwale stres toets is ontwikkel om larwale weerstand teen chemiese stres te bepaal. Daar is gevind dat 50% van geproduseerde larwes morfologiese abnormaliteite sal toon indien bevrugte eiers vir „n periode van 24 uur in 0.7% dimetiel sulfoksied (Me2SO) geïnkubeer word. Indien larwes minder abnormaliteite toon by hierdie konsentrasie, beteken dit dat hierdie larwes meer weerstand kan bied teen die negatiewe effek van die toksiese middel, en dus beskou kan word as goeie kwaliteit larwes met hoë lewensvatbaarheid. Met die evaluering van hibridisasie potensiaal tussen H. midae en H. spadicea, is gevind dat dit moontlik is om vrygestelde H. midae eiers te bevrug met H. spadicea sperm wat verkry is deur „n biopsie. Die implementering van hierdie studie se bevindinge in kommersiële H. midae produksiesisteme sal daadwerklik bydra tot die optimisering van bestuurspraktyke en „n verhoging in die totale produksie doeltreffendheid van sulke sisteme.
17

The evaluation study of Mashashane breeder farms and hatchery project.

Kganyago, Tshoshane Gladys 12 1900 (has links)
Thesis (M.Ed)--University of Limpopo,2009. / This report describes the research carried out at both the Mashashane Breeder Farms and Hatchery Project established at Newlands village (Mashashane), of Polokwane Municipality of the Capricorn region of Limpopo Province in South Africa. This research is about the sustainability of projects in Limpopo Province of South Africa. For this purpose, the Mashashane Breeder Farms and Hatchery Project is the case of this study. The study aimed at evaluating the sustainability of the Mashashane Breeder Farms and Hatchery Project, so as to make authorities aware of the difficulties experienced in sustaining projects, and to highlight those factors that make projects succeed. The following research questions were formulated for this study: • What are the critical factors that determine sustainability of projects? • What can be the role of adult education in this project? The intention of this study was to investigate why most projects collapse; and what kept the Mashashane Breeder Farms and Hatchery Project to exist for such a long time. In Chapter 2 of this study, I formulated assumptions about the sustainability of projects. I suggested certain factors to be considered for the purpose of sustaining a project. My assumptions were needs analysis; organising people; communication; competition; management; deliverables; lack of skills; ability to plan; project ownership and participation; the role of the government; and time table (schedule). In Chapter 3, the methodology is outlined. This study followed the qualitative approach. Instruments used for the collection of data are also explained. I discussed the main learning area, outlined the difficulties in carrying out the research activities and concluded the chapter by the model of data matrix. In Chapter 4 of this study, findings from Mashashane Breeder Farms and Hatchery Project are outlined, based on documents, interviews and observations of activities of the project. I formulated variables informed by Chapter 2 of this study. I report on the setting of the Mashashane Breeder Farms and Hatchery Project. In Chapter 5, I have outlined conclusions based on the study. The suggested points about a good project are tabled. Inclusive of the challenges faced by the Mashashane Breeder Farms and Hatchery project are, namely: mortality; infertility; no income period; and education and training of employees. In Chapter 6, I have given recommendations for this study. Some of the recommendations specifically for this project are, namely: more projects should be established to address unemployment and poverty; feedback should be given to employees; communication should be reciprocal, prior work experience be recognised; adult education should be introduced for employees to upgrade their skills and develop some; workshops should be arranged to improve lives of employees; and increasing production and competition is to be encouraged at all levels (internally and externally).
18

Investigation of Urolithiasis Occurring In Hatchery-Reared Trout in Utah

Dean, Ernest H., Jr. 01 May 1971 (has links)
The urolithiasis condition investigated occurred at a "hard water" hatchery in Utah after the trout were changed from a meat diet to a commercial pelleted fish feed as a sole sustaining diet in 1961. Numerous diet modifications proved unsuccessful in preventing urolithiasis at the hatchery. It was eventually determined that different commercial diets resulted in varied percentages of trout developing urolithiasis. The urolithic deposits found in the kidney tubules were amorphous and composed of calcium phosphate (apatite) and an organic matrix. Bacterial contamination of the kidneys was not an important factor in the formation of urolithiasis. Rainbow trout containing urolithic deposits showed gradual deposit regression when transferred into a "softer" water supply. Pelleted experimental diets containing sodium bicarbonate and/or sodium fluoride were fed to two strains of rainbow trout reared in a "softer" water supply normally causing no urolithiasis problems. The diets with the sodium bicarbonate added resulted in a significant occurrence of urolithiasis when fed to trout for 30 days. The addition of sodium fluoride to the diet was not significant in producing urolithiasis in trout. One experimental diet (low sodium bicarbonate-sodium fluoride) and one strain of fish (Soap Lake) appeared to influence the number of trout developing urolithiasis although the increase was not significant. All levels of statistical significance were tested at the 5 percent level.
19

An Architecture of Amelioration

Plagemann, Geoffrey Russell 01 August 2010 (has links)
Scar: A lingering sign of damage or injury, either mental or physical. Technological advancement scars the landscape. It has been our practice to ignore, or worse, hide these marks that have been made as society continues to advance. Industries past left us relics and ruins of bygone eras of promise and production. The time we live in has recognized the untenable failures of past generations, however there are methods of industry that continue to injure the landscape. We will leave our scars. In this time we must rethink the scar, define it, and recognize its beauty. The first step of reclamation is acquiring awareness of where the scar came from. Whether it is an injury, an accident, or a natural disaster, some traumatic event caused lasting damage. Traumatic events whether natural - hurricanes, floods and earthquakes - or manmade - wars, genocide and assaults - can cause both physical and emotional scars. Human tissues can repair themselves leaving scars, but there are also the scars of repair. Even technological advancements in medicine cannot eliminate the scar. Scarring is the natural healing process, yet we view them as unnatural. Once recognized, we must accept the scar so that we do not destroy it. We must accept the traumatic cause/effect relationships, and be conscious of the healing process. The scar must be appreciated: the time that it takes to make it, the time that it takes to heal, the history it can teach, and the story that it can tell. To hide it would only be an injustice to those who came before us and to those yet to come. With acceptance a scar’s beauty can be seen. Every new era of technology, every successive generation, leaves a scar. The opportunity to aid the greatest healer – time – is now. Every scar tells a story. Reclamation: A restoration, as to productivity, usefulness, or morality.
20

Contrasting survival strategies of hatchery and wild red drum: implications for stock enhancement

Beck, Jessica Louise 15 May 2009 (has links)
Post-release survival of hatchery fishes is imperative to the success of any supplemental stocking program. The purpose of this research was to identify differences between hatchery and wild red drum (Sciaenops ocellatus) and determine if pre-release exposure techniques improve survival of hatchery individuals. Objectives were to contrast survival skills of hatchery and wild red drum from different locations, and examine if exposure to natural stimuli (e.g., habitat, predators, live prey) enhances survival skills in naïve hatchery red drum. Laboratory trials using high-speed videography (250 frames per second, fps) and field mesocosm experiments were used to investigate differences in prey-capture (e.g., attack distance, mean attack velocity, capture time, maximum gape, time to maximum gape, gape cycle duration, and foraging behaviors) and anti-predator performance (e.g., reaction distance, response distance, maximum velocity, time to maximum velocity, mean acceleration, and maximum acceleration) of hatchery and wild red drum. Results indicated that anti-predator performance measures differed significantly between hatchery and wild red drum. Variability in prey-capture and anti-predator performance for hatchery and wild red drum was high (CV range: 5.6 – 76.5%), and was greatest for hatchery fish for the majority of performance variables tested. Exposure to habitat (Spartina alterniflora marsh) did not appear to afford any obvious survival benefits to hatchery red drum, although survival skills did vary according to ontogenetic stage. Hatchery red drum exposed to natural predators (pinfish, Lagodon rhomboides) exhibited significantly greater attack distances during feeding events, and anti-predator performance variables were 20 – 300% in these individuals versus naïve red drum. In predation experiments with free-ranging pinfish predators, mortality rates (Z) ranged from 0.047 – 0.060 h-1 · predator-1; however no significant differences in mortality were found between fish reared with and without predators. Hatchery red drum reared on live prey (Artemia franciscana, mysid shrimp) demonstrated enhanced prey-capture and foraging behaviors as well as anti-predator performance relative to fish reared on artificial (pellet) diets. Findings of this research indicate that several behavioral patterns differed between hatchery and wild red drum; however, these differences can be mediated through the use of various pre-release exposure techniques.

Page generated in 0.0536 seconds