Thesis (MBA)--Stellenbosch University, 1998. / ENGLISH ABASTRACT: The techniques for animal reproduction and husbandry for both abalone and sea turtle farming have been well established and researched over the last decade. Although market related data seems to be scarce, marketing analysis reviewed and conducted as part of this study suggests that extensive markets exist for live cocktail size abalone and sea turtle products, especially in the East Asian countries. A decline in natural resources and increased demand resulted in a fast expanding niche market for these products. This study shows that development of an abalone farm in South Africa for the production of cocktail size (±80 mm; ±100 g) is a highly profitable venture. Economic feasibility analysis indicated that the development of an abalone farm capable of producing 150 tons annually should result in a rate of return in excess of 50% over a seven-year investment period. On the other hand, sea turtle farming is a less profitable investment with Green turtle farming yielding a return of approximately 25% and Hawksbill farming yielding a return closer to 30% over a seven-year investment period. According to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), all sea turtle species have been listed as endangered or threatened. Currently all countries who are members of CITES are prohibited from international trade in sea turtles or sea turtle products. Prospective entrepreneurs wishing to establish a sea turtle farming venture have to adhere to stringent regulatory and control measures, a major obstacle in the development of a profitable enterprise. Both abalone and sea turtle farming have long payback periods, due to the slow growth-rates of the investigated species. In order to produce animals in a time frame that is economically viable, artificially formulated feeds have to be used. The usage of artificially formulated feeds proved to be a major expense, especially in the case of sea turtle farming. / AFRIKAANSE OPSOMMING: Die tegnieke vir die reproduksie, onderhoud en groei van beide perlemoen en seeskilpad akwakultuur boerderye is goed gevestig en nagevors oor die afgelope dekade. Alhoewel mark verwante data skaars is, dui bemarking analises aan dat 'n enorme mark bestaan vir lewendige "cocktail" grootte perlemoen en seeskilpadprodukte, veral in Oos Asie. 'n Afname in natuurlike hulpbronne en 'n toename in aanvraag, het 'n vinnige "nis" mark vir die produkte tot gevolg gehad. Die ontwikkeling van 'n perlemoen boerdery vir die produksie van "cocktail" grootte (±80 mm; ±100 g) perlemoen kom voor as 'n hoogs winsgewende onderneming. 'n Ekonomiese winsgewindheidsanalise het getoon dat die ontwikkeling van 'n perlemoenplaas, met 'n produksie van sowat 150 ton perlemoen jaarliks, 'n opbrengs van oor die 50% oor 'n sewe jaar investeringsperiode teweeg sal bring. Seeskilpad boerdery, aan die ander kant, kom as 'n minder winsgewende belegging voor, waar Groen seeskilpad boerdery 'n opbrengs van ongeveer 25% en Hawksbill boerdery 'n opbrengs van min of meer 30% oor 'n sewe jaar beleggings periode toon. Volgens CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) is alle seeskilpaaie gelys as bedreig. Alle lande wat huidiglik lede is van CITES, word van die reg voorbehou om internasionale handel te dryf in seeskilpaaie of seeskilpadprodulcte. Voorgenome entrepeneurs met die begeerte om 'n seeskilpadboerdery te begin, sal voor streng maatreels en beheer- maatstawwe te staan kom, wat 'n groot stuikelblok is in die ontwikkeling van 'n winsgewende seeskilpadplaas. Beide perlemoen- en seeskilpadboerderye het lang terugbetalingsperiodes, 'n waameming wat verduidelik kan word aan hand van die stadige groei-tempo's van die bestudeerde spesies. In orde om diere in 'n spesifieke tydsperiode te produseer wat ekonomies winsgewend is, moet daar van artifisieel geformuleerde voeding gebruik gemaak word. Die gebruik van geformuleerde voeding. is egter duur, veral in die geval van seeskilpadboerderye.

<div>Inferring genetic population structure in endangered, highly migratory species such as sea turtles is a necessary but difficult task in order to design conservation and management plans. Genetically discrete populations are not obvious in highly migratory species, yet require unique conservation planning due to unique spatial and behavioral life-history characteristics. Population structure may be inferred using slowly evolving mitochondrial DNA (mtDNA), but some populations may have diverged recently and are difficult to detect using mtDNA. In these cases, rapidly evolving nuclear microsatellites may better elucidate population structuring. Bayesian inference and ordination may be useful for assigning individuals to inferred populations when populations are unknown. It is important to carefully examine population inference results to detect hierarchical population structuring, and to use multiple, mathematically diverse methods when inferring and describing population structure from genetic data. Here I use Bayesian inference, ordination, and multiple genetic analyses to investigate population structure in Olive ridley sea turtles (ORs; Lepidochelys olivacea) nesting in northwestern Costa Rica (NWCR) and across the entire Eastern Tropical Pacific (ETP). Mitochondrial DNA did not show structure within NWCR, and existing data from prior studies are not appropriately published to compare NWCR to Mexican ORs. In NWCR, Bayesian inference suggested one population, but ordination suggested four moderately structured populations with high internal relatedness, and moderate to high levels of connectivity. In the ETP, Bayesian inference suggested a Mexican and Central American population, but hierarchical analysis revealed a third subpopulation within Mexico. Ordination revealed nine cryptic clusters across the ETP that primarily corresponded to Mexican and Central American populations but contained individuals from both populations, some from other, distant nesting sites. The subpopulation within Mexico was well-defined after ordination, and all clusters displayed high 10 internal relatedness and moderate genetic differentiation. Bottlenecks were detected in both putative populations, at seven Mexican and two Central American nesting beaches, and in six out of nine inferred clusters, including three out of four Mexican clusters. Bottleneck events may have played some role in cluster differentiation. Migration was significant from Mexico to Central America at multiple levels, but did not necessarily agree with potential migrants elucidated by ordination. Migration was generally lower between ordination-inferred clusters than between nesting sites or Bayesian-inferred clusters. Phylogenetic trees generally supported structuring by ordination, rather than by Bayesian inference. Structuring in ordination not tied to bottleneck events could be due to mating behaviors or patterns of nesting beach colonization dictated by environmental features. In this study, ordination provided a more practical and nuanced framework for defining MUs and DIPs in ETP ORs than did STRUCTURE. This may be due to hierarchical structuring within ETP ORs that may be present in other sea turtle populations and species. In the case of ETP ORs, hierarchical structure may be an artefact of recent population bottlenecks and subsequent recolonization of nesting beaches, or due to mating at foraging grounds or along migratory routes. Bayesian inference may not be the best method for population inference in highly migratory species such as sea turtles, which have a high potential for broad scale genetic connectivity, and therefore may display hierarchical population structuring not easily related to nesting sites. Future studies, and perhaps published studies, should incorporate Bayesian inference and ordination, as well as other measures of population divergence and descriptive statistics, when searching for population structure in highly migratory species such as sea turtles.</div>

In the southeastern United States, skimmer trawls, pusher-head trawls, wing nets, and small try nets (headrope length less than 12-ft (3.66-m)) are exempt from using a turtle excluder device (TED) and instead must adhere to tow time restrictions as a mode to mitigate sea turtle bycatch. However, observer and stranding data indicate that these tow times may often be exceeded and result in mortality of sea turtles. The National Marine Fisheries Service (NMFS) published a notice of proposed rulemaking in December 2016 to extend TED requirements to other trawl types, however there has been limited development of specialized TEDs for these smaller trawls. In anticipation of a regulatory change, we developed and identified multiple versions of a top-opening TED with a minimum width of 28-in (71-cm) and height of 24-in (61-cm) as the best option for small trawl gears. Prototypes were initially equipped within small try nets and tested for gear performance and sea turtle exclusion in Panama City, Florida. The final designs were then tested for target shrimp retention, bycatch reduction, and general usability of TEDs in the commercial fisheries. A paired comparison test was conducted in 8-ft (2.44-m) and 10-ft (3.05-m) try nets aboard the NMFS R/V Caretta, three commercial skimmer trawls in vesselsFarfantepenaeus duorarum) fishery. There was a general reduction of shrimp and bycatch averaging from a minimum loss of 3.31% in the Miami wing net fishery (FV FL-01) to 22.07% in the skimmer trawl fishery (FV LA-01). This dissertation research indicates that TEDs can function properly in small trawl types, however additional studies are recommended to minimize the shrimp loss and improve the overall TED effectiveness specific to each fishery and trawl type evaluated.

Intestinal HCO3- secretion and the excretion of resultant CaCO3 precipitates have become a recognized characteristic of seawater osmoregulation in teleosts; however, this is the first report of this osmoregulatory strategy outside of teleosts and also includes evidence for its use in green turtles, Chelonia mydas. Furthermore, the effects of feeding on intestinal HCO3- secretion were newly investigated in teleosts. Intestinal base secretion via apical Cl-/HCO3- exchange was found to increase following feeding, at a magnitude sufficient to offset the "alkaline tide" commonly associated with digestion. Intestinal HCO3- secretion in marine teleosts draws HCO3- from both endogenous (via hydration of intracellular CO2) and serosal (blood) sources, of which serosal HCO3- was found to contribute a greater proportion to the elevated postprandial intestinal base secretion measured in gulf toadfish, Opsanus beta. The mechanism by which this serosal HCO3- crosses the basolateral membrane for subsequent secretion into the intestinal lumen was confirmed in toadfish to be a basolateral Na+/HCO3- co-transporter, tfNBCe1. Furthermore, the isolated intestinal tissue was found to have a high metabolic rate in both control and postprandial toadfish, with respect to that of the whole animal, and shows a considerable specific dynamic action (SDA) response to feeding. Overall, this dissertation provides evidence for the widespread use of intestinal HCO3- secretion as a strategy of marine osmoregulation across aquatic taxa, and also for its newly recognized involvement in postprandial acid-base balance.

Anecdotal reports, flipper tag returns, satellite migration paths, and above-water and net surveys have identified an important foraging area for sea turtles in the Robinson Point area, 12 kilometers southwest of Belize City. Visual observations confirmed that sea turtles were actively foraging at Robinson Point. Sixteen 30 minute visual observations from stationary and drifting boats made 132 sea turtle sightings from October 2007 through January 2008, with a maximum of 40 sightings made in one survey. In-water capture methodology tested the traditional turtle net, which captured 14 turtles in 63 sets for a success rate of only 22%. There were 11 green turtles captured during the migratory months from April through October, and three hawksbill turtles were captured during non-migratory months, November through March, indicating that both species were resident at Robinson Point. No loggerheads, adult males, or juvenile turtles were captured, but anecdotal reports confirmed presence. Size range for captured hawksbills was between 63.7 - 80.4 cm SCLnn and between 70.9 - 91.5 cm SCLnn for green turtles. There were two recaptured turtles. One was a nesting hawksbill tagged in Mexico in 2008 and recaptured at Robinson Point in 2009, and the other was a sub adult hawksbill that was captured at Robinson Point in 2008 and recaptured in 2013 in Nicaragua. There was a small growth of fibropapilloma on one green turtle. Habitat surveys suggest benthic communities are more diverse than previously described consisting of prey items sought by sea turtles. Geomorphology of the Robinson Point area is equally diverse and provides shelter for resident turtles. Proposed boundaries for a turtle conservation zone at Robinson Point and an internesting zone to protect turtles at Belize premier hawksbill nesting beach at Gales Point, are linked to existing protected areas, and would facilitate protection of sea turtles not only in Belize, but also throughout the Caribbean.

The beaches of Broward County, Florida are a prevalent nesting site for loggerhead (Caretta caretta) sea turtles, however extensive beach erosion is threatening critical nesting habitat. Beach renourishment, the process of transporting offshore or upland sediment onshore, is a widely used method of replenishing lost sand. However, renourishment can negatively affect sea turtle nesting habitat by increasing beach compaction; the resistance to applied pressure in pounds per square inch (psi). Increased sand compaction impedes the digging of the female which affects nesting success. The influence of beach compaction on sea turtle nesting patterns has never been previously examined over the course of a nesting season on Hillsboro and Deerfield Beach. Therefore, this study was designed to examine beach compaction data for Hillsboro, a mostly natural beach, and Deerfield, a completely renourished beach, during the 2010 nesting season and analyze the compaction data against 2010 nest and false crawl (FC, non-nesting emergence) data. Compaction readings were collected during every other week March-October using a soil compaction meter at every other street address along three beach positions, the dune base, mid-beach, and average high tide line (HTL); and at three depths, 15 cm, 30 cm, and 45 cm. Values were not statistically different throughout the season for each beach, so seasonal mean compaction values were used for each beach position and depth. Hillsboro compaction values were rarely over 500 psi (35 kg/cm2), even at 45 cm depth. Deerfield compaction values exceeded the 600 psi (42kg/cm2) measurement limit of the meter in approximately 60% of the compaction values at 30 cm or 45 cm depth. Sand compaction data was analyzed for any trends between beaches as well as within each beach. Historical data shows higher loggerhead nesting success, the number of nests/total number of crawls (including FC) x 100, on Hillsboro Beach than on Deerfield Beach. The average beach compaction values were compared to nesting success and to nest and FC density within each station area. There was a significant inverse relationship (p<0.05) between beach compaction and nesting success at each of the beach positions and depths, when both Hillsboro and Deerfield Beaches were analyzed together, except at the Mid 30 cm and Dune 45 cm depth. The strongest relationship for the combined beaches was at the HTL 15 cm depth (R2=0.3821, p<0.001). When Hillsboro was analyzed alone, beach compaction and nesting success was only significantly inversely related (R2=0.0875, p<0.02) at the HTL 15 cm depth. This demonstrates that while increased beach compaction may partially influence nesting success, there are likely other beach characteristics that contribute to nest site selection of loggerheads in Northern Broward County. The inverse relationship between Hillsboro mean beach compaction and nest density (nests per meter) was significant only at the HTL 15cm depth (p<0.002) and the inverse relationship between mean beach compaction and false crawl density (FC per meter) in Hillsboro was only significant at the Dune 15 cm (p<0.019) and the Dune 30 cm (p<0.038) depths. Although, increased beach compaction was expected to relate to higher FC density, FC density showed a significant inverse relationship to mean beach compaction at all Deerfield Beach positions and depths in and this suggests off-shore factors may be affecting nest site selection.

The purpose of this thesis was to determine the extent of sea level rise (SLR) impact on sea turtle nesting beach habitat on Archie Carr National Wildlife Refuge (NWR) as well as impacts on management strategies. The Archie Carr NWR is of exceptional importance due to the high density of Loggerhead, Leatherback, and Green sea turtles that nest there in the summer months. GIS data provided by the Archie Carr NWR and various SLR scenarios, provided by both the Intergovernmental Panel on Climate Change (IPCC) as well as leading scholars, were used to determine inundation area loss across the Refuge as well as nearby parcels targeted for possible acquisition. Inundation losses for the six scenarios were calculated to be in the 20-25% range. Approximately 26% of current lower priority parcels are reclassified as high priority when integrating this information. Therefore, a significant revision to future acquisition strategies is recommended.

<div>Sea turtles are integral components of many marine ecosystems. Green turtles (Chelonia mydas) are generally herbivorous, feed primarily on seagrasses, and are endangered in the Caribbean. The species utilizes extensive marine habitats for foraging and migratory routes, and because of its broad distribution, it is difficult to conduct population assessments. Here, I assessed commonly used techniques for monitoring green turtles in the wild. Specifically: (1) biopsy sampling for molecular assays and (2) unoccupied aerial vehicles (UAVs) deployment and boat-based surveys for population monitoring.</div><div><br></div><div>Skin biopsies are collected from sea turtles for a variety of molecular analyses; however, very little information exists on the natural healing rates at the site of the biopsy in the wild. In Chapter 2, I monitored the healing rates of 17 juvenile green turtles in Eleuthera, The Bahamas, for up to 488 d after taking a 6mm biopsy tissue sample. Complete tissue repair and maturation was observed after a year and a half, and there was no evidence of infection at any point during the healing process. While scarring persisted for several months, biopsy sampling had minimal long-term impact.</div><div><br></div><div>UAVs are increasingly being used to monitor marine megafauna. In Chapter 3, I evaluated the efficacy of using UAVs to detect sea turtles when compared to boat-based surveys. During UAV surveys, the UAV was flown along preprogrammed routes in four creek systems. A boat survey was conducted simultaneously on the same path. I used regression analyses for each survey type to assess the effects of environmental variables on turtle detection rates My results indicate that there were no statistically significant difference between the numbers of turtle detected via boat or UAV surveys; however, there were clear differences in the time and potential cost associated with either method.</div>

One of the principles regarding our knowledge about life on earth is that no organism can be fully understood without taking into account its surrounding environment. This study examines the extent to which ecosystem-focused field studies may be associated with students' academic performance and potential to contribute to the advancement of science and conservation. Pilot studies conducted in Panama and California established methods used in this project from 1993-2003. Two hundred and sixty-seven students conducted field studies in either Kenya or Costa Rica. Students worked in cognitive apprenticeships, in which research staff trained each student to conduct field research. At the conclusion of their fieldwork, the research staff assessed the students written field reports. The students' reports were then sorted according to the extent to which their studies were ecosystem-focused. Data analysis through nonparametric, Kruskal-Wallis statistical tests revealed no significant difference in academic performance on field study reports, in regards to whether the studies were narrow in scope (species-specific) or broad (ecosystem-focused). Marginal significance was revealed between ecosystem-focused studies and the potential for students' fieldwork to contribute to the advancement of science and conservation. Also addressed in the data were injuries, disease, and potential hazards, which were influenced by prudent and decisive leadership. Successful field studies require consideration of the content, context, and design of the intended field projects. Many of the solutions to environmental problems on the planet will come from the working hands of teachers and students that conduct explorations in the field. / Life Sciences in Education / D. Phil. (Mathematics, Science and Technology Education)

A tartaruga verde (Chelonia mydas) é uma tartaruga marinha que se alimenta e nidifica em locais da costa brasileira, ilhas e atóis. Esta espécie tem sido acometida pela fibropapilomatose (FP), doença considerada como uma das mais importantes ameaças à sua sobrevivência e caracterizada por tumores cutâneos benignos. A etiologia é multifatorial e complexa, possivelmente havendo relação entre Chelonid Fibropapilloma-associated Herpesvirus, fatores ambientais e genéticos. Foram estudadas 133 tartarugas verdes com e sem tumores provenientes de cinco áreas brasileiras: Florianópolis/SC, Ubatuba/SP, Vitória/ES, Almofala/CE e Fernando de Noronha/PE. Foram obtidos dados de biometria (comprimento curvilíneo da carapaça-CCC, massa corporal-MC e índice de condição corporal-ICC), tamanho (classificado por categorias A, B, C e D), quantidade e localização anatômica dos tumores, além da colheita de amostra sanguínea. Os objetivos foram (1) avaliar a atividade dos leucócitos por citometria de fluxo (fagocitose e burst oxidativo); (2) investigar a presença de sete congêneres de bifenilas policloradas (PCBs) e (3) estabelecer correlações entre PCBs e a atividade dos leucócitos. Houve diferenças no CCC entre tartarugas sem tumores de acordo com a área de estudo, na MC e no ICC entre animais acometidos ou não capturados em Ubatuba. Foram quantificados e classificados 1033 tumores de 50 tartarugas verdes, sendo que a quantidade por tartaruga variou de 1 a 61 e a maior parte foi classificada nas categorias de tamanho A (446 tumores) e B (520 tumores) e na região anterior (669 tumores). Foi observada diferença significativa nas concentrações do congênere PCB 138 entre tartarugas com e sem FP capturadas em Vitória. Animais acometidos tiveram maiores concentrações de todas as PCBs quantificadas, exceto as tartarugas verdes capturadas em Vitória no caso dos congêneres PCBs 118, 138, 153 e 180. PCB 138 foi quantificado em maior concentração nas amostras e PCB 180 em níveis menores. Não foram observadas correlações significativas entre concentrações de PCBs e atividade celular. A FP tem sido amplamente pesquisada e os estudos que visam estabelecer correlações entre poluentes químicos e saúde animal são extremamente importantes, pois podem contribuir para novas direções nos planos de ação para conservação. / The green sea turtle (Chelonia mydas) feeds and nests in Brazilian coast, islands and atolls. This species has been affected by fibropapillomatosis (FP), disease considered one of the most important threats to its survival and characterized by benign skin tumors. The etiology is multifactorial and complex, possibly having relation between Chelonid Fibropapilloma-associated Herpesvirus, environmental and genetic factors. Were studied 133 green sea turtles with and without FP from five Brazilian areas: Florianópolis/SC, Ubatuba/SP, Vitória/ES, Almofala/CE and Fernando de Noronha/PE. Were taken biometric data (curved carapace length-CCL, body mass-BM and body condition index-BCI), as well as size (classified by categories A, B, C and D), numbers and anatomical distribution of tumors, besides blood sample collection. The aims were (1) to assess leukocytes activity by flow cytometry (phagocytosis and oxidative burst); (2) to investigate the presence of seven congeners of polychlorinated biphenyls (PCBs) and (3) to establish correlations between PCBs and leukocytes activity. There were differences in CCL between turtles without FP according to the study area, in BM and BCI between affected and non-affected animals caught in Ubatuba. Were quantified and classified 1033 tumors of 50 green sea turtles, the number of tumors ranged from 1 to 61 and the most part of them was classified in categories of size A (446 tumors) and B (520 tumors) and in anterior region (669 tumors). Was observed difference in PCB 138 concentrations between green sea turtle with and without FP caught in Vitória. Affected animals had higher concentrations of all PCBs quantified, except green sea turtles caught in Vitória in the event of PCBs 118, 138, 153 and 180. Were quantified highest concentrations of PCB 138 and lowest of PCB 180. There were not significant correlations between PCBs concentration and leukocyte activity. The FP has been widely investigate and the studies that aimed to establish correlations between pollutants and animal health are very important, because can contribute for new directions in sea turtle conservation issues.