Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (M.Sc.) - University of Queensland, 2002. / Includes bibliography.

Crocodylus porosus is the most widely distributed crocodilian species and suffered widespread population decline during the 20th century, principally due to commercial hunting for their hides, but also from habitat destruction and persecution. An estimated 270,000 to 330,000 animals were killed in Australia before the species was protected in the early 1970s. Populations of C. porosus in Western Australia are poorly studied and the number of animals taken during the hunting era is unknown. However, by 1970, hunting was no longer considered to be commercially viable. Over the last two decades, adding commercial value to crocodiles through sustainable use has been an integral part of the management strategy throughout Australia. Despite this, demographic parameters remain unquantified for most life-history stages. This study attempts to provide quantified demographic information for some populations of C. porosus in Western Australia. Patterns of movement are a fundamental component to the dynamics of animal populations. VHF radio tags were attached to 16 estuarine crocodiles, which were tracked between October 2001 and May 2003. Male (n = 12) and female (n = 4) crocodiles exhibited distinctly different patterns of movement. Females occupied a small core linear range (1.3 &plusmn; 0.9 km) on the main river channel during the dry season and moved distances of up to 62 km to nesting habitat during the wet season, returning to the same core area the following dry season. Males moved considerable distances along the Ord River throughout the year. The largest range recorded was 87 km for a 2.5 m juvenile male, which had not stabilized. However, male ranges did not appear to be related to body size, with the largest two ranges recorded for the smallest (2.5 m) and largest (4.3 m) males tagged. Rates of male movement did not differ significantly between three size classes of males but there were significant seasonal differences, with the highest mean rates of movement occurring during the summer wet season (4.0 &plusmn; 5.4 km/d). The highest rate of sustained movement was 9.8 km/d for a translocated 2.6 m juvenile male, which travelled 118 km in 12 days to return to the area of its capture. Neither males nor females showed exclusive habitat preferences for any of four broad riverine habitats identified on the Ord River. Males had substantial range overlaps with no obvious spatial partitioning, suggesting territoriality is not an important behavioural characteristic of free-ranging male crocodiles along the Ord River. Rates of migration were also examined indirectly using genetic data, which integrates patterns of movement at the population level over many generations. One hundred and twenty three tissue samples were collected from three river systems between April 2001 and September 2002. Levels of genetic diversity and structure were quantified at nine microsatellite loci. Genetic data indicated that C. porosus shows strong site fidelity. However, indirect estimates of migration from fixation indices suggest gene flow is sufficient to maintain genetic diversity and population substructure but not so low as to cause inbreeding. Genetic diversity was similar in all three populations examined with allelic richness ranging from 4.6 to 5.0 alleles per locus and mean observed heterozygosity ranging from 0.63 to 0.74. Inbreeding coefficients indicated there was only moderate differentiation among the populations (FST = 0.08, RST = 0.06) but differences in allele frequencies were highly significant. Assignment tests designated 80% of individuals to their population of origin and identified only five individuals (4%) as first generation migrants. Populations that experience a severe and rapid reduction in size, such as occurred with C. porosus following the Second World War, are susceptible to losing a significant component of their genetic variation. There was compelling evidence for a recent genetic bottleneck in the three populations sampled. Survivorship in C. porosus in unknown for most life-history stages so a mark-recapture study was implemented to investigate the dynamics of the C. porosus population in the King River. A total of 162 animals were marked between June 2001 and July 2002 of which 75 marked animals were recaptured on 123 occasions. The size of the hatchling population (age < 1 year old) was estimated to be 91 &plusmn; 2 (SE) in 2001, which was effectively an estimate of successful recruitment for the King River during that year. The size of the non-hatchling population (age >1 year old) was estimated to be 69 &plusmn; 13 but the precision of the estimate was low and should be treated cautiously. Survival of the 2001 cohort of hatchlings was high (> 95%) between June and December and did not vary between the sexes. Hatchlings grew rapidly from June 2001 to July 2002, doubling in length and showing a ten-fold increase in body mass. There were no significant differences in growth rates between females and males during the first 18 months of life. Crocodiles showed a significant behavioural response to capture, with capture probabilities decreasing over time for two groups classified by age. Furthermore, differences in capture probabilities between age groups were significant on all occasions. This has important implications for monitoring crocodile populations, particularly if sightability is influenced by human disturbance. This study has provided some insights into important ecological processes operating within Western Australian populations of C. porosus, but the number of populations examined and period of study were small for such a long-lived animal. More work is needed to determine whether the patterns that have emerged are typical throughout the species' range and longer term studies will be required to quantify vital statistics for most life stages.

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Submitted by (ana.araujo@ufrpe.br) on 2016-08-01T18:51:08Z No. of bitstreams: 1 Leandro Ricardo Rodrigues de Lucena.pdf: 3149827 bytes, checksum: 027bfb5db60c84de41a58b9281c7c64a (MD5) / Made available in DSpace on 2016-08-01T18:51:08Z (GMT). No. of bitstreams: 1 Leandro Ricardo Rodrigues de Lucena.pdf: 3149827 bytes, checksum: 027bfb5db60c84de41a58b9281c7c64a (MD5) Previous issue date: 2012-09-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The genus Rhizoprionodon (Whitley, 1929) comprises seven species occurring in the Atlantic, Pacific and Indian Oceans; the species are small and medium-sized animals attaining about 150 cm, inhabiting coastal waters, estuaries and brackish waters and feeding mainly on mollusks, crustaceans and small fish. In Brazil the two species are found Rhizoprionodon porosus (Poey, 1861) and lalandi (Valenciennes, 1839). The use of morphometric approaches has limitations for this group due to lack of anatomical landmarks, since they have a continuous form without angles. This study will analyze the chondrocranium a structure that is considered species-specific, located at the base of the skull holding and protecting the brain, displaying a shape that exhibits numerous angles. The study aims to verify the hypothesis suggested in the literature of two populations of the species R. porosus off northeastern Brazil (Lessa et al. 2011; Lessa et al. 2008). One corresponds to the northern coast of the Northeast (RN) and the other to the eastern coast of this region (PE). For that we performed a comparative morphometric study of the chondrocranium of R. porosus between the indicated areas using multivariate analyses. Thus, there were differences both for adult and juvenile phases by regions of capture. The discriminant analysis and k-means yielded a hit rate of 100, 0%. In conclusion, there is indeed a difference between chondrocrania from Pernambuco and Rio Grande do Norte as showed by approaches used. These results are in accordance with the hypotheses recently suggested in the literature that indicates two populations on the coast of northeastern Brazil. / O gênero Rhizoprionodon (Whitley, 1929) compreende sete espécies distribuídas pelos oceanos Atlântico, Pacífico e Índico. No Brasil ocorrem duas espécies, o Rhizoprionodon porosus (Poey, 1861) e o lalandi (Valenciennes, 1839). O uso de técnicas morfométricas distintas da abordagem que utiliza proporções corporais, geralmente utilizadas em taxonomia, encontra limitações para esse grupo devido à falta nos elasmobrânquios de marcos anatômicos, propriamente ditos. Assim, no presente estudo será analisado o condrocrânio que é uma estrutura considerada espécie-especifica que apresenta forma angulosa, localizado na base do crânio que sustenta o encéfalo e serve para sua proteção. O estudo tem por objetivo verificar a hipótese sugerida na literatura de duas populações da espécie R. porosus na costa do Brasil (Lessa et al. 2011; Lessa, 2003). Uma delas corresponderia à costa setentrional do Nordeste (RN) e a outra à costa oriental desta região (PE). Para tanto, se realizou um estudo morfométrico comparativo do condrocrânio de R. porosus entre as regiões mencionadas utilizando-se para isso os métodos de análise multivariada. Em todas as análises verificou-se diferenças tanto para a fase adulta quanto para a fase juvenil em relação às regiões de captura. Na análise de discriminantes e no k-means obteve-se uma taxa de acerto de 100,0% na classificação dos condrocrânios. Não existe diferença do condrocrânio em relação ao sexo independente da região de captura. As variáveis que caracterizaram as diferenças entre as populações foram: a distância entre as fenestras rostral e baserostral, a distância entre a fenestra rostral e as cartilagens lateral rostral esquerda e direita e a distância entre a fossa pariental e a fontanela anterior, sendo que exemplares de R. porosus do RN apresentaram distâncias maiores. Verificou-se de fato diferença entre os condrocrânios de PE e RN nas fases adulta e juvenil. Esses resultados estão em conformidade com o padrão recentemente sugerido na literatura que indica duas populações na costa nordeste do Brasil.

Submitted by (ana.araujo@ufrpe.br) on 2016-08-12T13:29:10Z No. of bitstreams: 1 Rosangela Maria de Souza Silva.pdf: 1095943 bytes, checksum: 114a6bb1a30593012f294c2b2e0419d5 (MD5) / Made available in DSpace on 2016-08-12T13:29:10Z (GMT). No. of bitstreams: 1 Rosangela Maria de Souza Silva.pdf: 1095943 bytes, checksum: 114a6bb1a30593012f294c2b2e0419d5 (MD5) Previous issue date: 2014-07-18 / Belonging to Carcharhinidae family, Rhizoprionodon porosus and R. terraenovae are may be confused as to the specific status, and most often has only the geographical criteria is used for discriminating to the species level as R. porosus is distributed only on the east coast of the American continent and R. terraenovae occurs in the west coast of the Atlantic in the Northern Hemisphere. The analysis of morphometric characters of the two species R. porosus and R. terraenovae, was conducted to ascertain differences in body shape, since genetic differences found using molecular markers of mitochondrial DNA may already have been morphologically expressed. To this end, measures 59 that are homologous parts of the body of 150 male and female newborns, and juveniles and adults were analyzed. Of these, 106 were R. porosus 44 were R. terraenovae collected in Brazil (off Pernambuco and Rio Grande do Norte states) or came from the collections of six different Museums; (MN / UFRJ), (MZUSP), (MOVI) (MNHN), (FMNH) and (FMNH). Univariate analyses indicated significant differences in measurements between species, which were observed in the multivariate analyses, depicted in projections of the first principal component ending up in a discriminant model made up of 4 measures, which classified species correctly with an mean accuracy of 81%. Therefore, the morphometric analyses confirm that the two species are distinct taxons delimited between the Gulf of Mexico and the northern Caribbean, suggesting an allopatric distribution. / Pertencentes a família Carcharhinidae, as espécies Rhizoprionodon porosus e Rhizoprionodon terraenovae podem ser confundidas quanto ao status específico, tendo na maioria das vezes apenas o critério geográfico para identificação, já que R. porosus se distribui apenas no Oceano Atlântico, na costa oriental do continente americano e R. terraenovae na costa Atlântica oeste no Hemisfério Norte. Análise de caracteres morfométricos de duas espécies do gênero Rhizoprionodon, R. porosus e R. terraenovae, foi conduzida a fim de verificar diferenças na forma do corpo, visto que diferenças genéticas foram encontradas utilizando marcadores moleculares do DNA mitocondrial. Para tanto, foram analisadas 59 medidas de partes homólogas do corpo de 150 exemplares machos e fêmeas de neonatos, jovens e adultos de Rhizoprionodon, sendo 106 R. porosus e 44 R. terraenovae originados de coletas realizadas no Brasil (litoral dos estados de Pernambuco e do Rio Grande do Norte) e exemplares das coleções de 6 Museus; (MN/UFRJ), (MZUSP),(MOVI), (MNHN), (FMNH) e (FMNH). A análise univariada indicou diferenças significativas nas medidas entre espécies, evidenciadas também na análise multivariada e visualizadas pela projeção das primeiras componentes principais e no modelo discriminante composto de 4 medidas, o qual classifica as espécies corretamente com acurácia média de 81%. Portanto, as análises morfométricas confirmam que as duas espécies constituem taxons distintos delimitadas entre o Golfo do México e o Norte do Caribe, o que sugere uma distribuição alopátrica.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-11-06T14:36:09Z No. of bitstreams: 1 Ana Cecilia Mamede Garcia.pdf: 1986623 bytes, checksum: a2e063d73475c143e1f43593ed5fc125 (MD5) / Made available in DSpace on 2017-11-06T14:36:09Z (GMT). No. of bitstreams: 1 Ana Cecilia Mamede Garcia.pdf: 1986623 bytes, checksum: a2e063d73475c143e1f43593ed5fc125 (MD5) Previous issue date: 2008-08-27 / The status of the two distinct the species Rhizoprionodon porosus and Rhizoprionodon terraenovae is not yet ascertained. The identification at the species level of fishery resources is imperative not only for their own ecologic value, but also under the point of view of their management. Multivariate analyses of a set of phenotypic characters can be considered as an appropriate method to elucidate morphologic relations between different species or populations. The morphologic discrimination standards between Rhizoprionodon porosus and Rhizoprionodon terraenovae has been studied through techniques of multivariate analysis with the aim to evaluate the status of the species and to determine which morphometric characters can be used in the discrimination. On basis of 79 individuals collected in 3 localities (Pernamuco e Rio Grande do Norte, Brasil e Flórida, EUA) and 67 paratyps of both species deposited in the Museums MN/UFRJ, MZUSP, MOVI, MNHN and FMNH, Multivariate analyses have been carried out on the basis of 64 morphometric measurements. The results indicate differences between Rhizoprionodon porosus and Rhizoprionodon terraenovae. Distinct groups of both species formed clusters and were analyzed by discriminant analyzes. Units with divergent classification correspond to the region of Central America. Overall, differences suggested that they are two distinct simpatricas species highly miscegenated in the area of Central America. / O status atual de Rhizoprionodon porosus e R. terraenovae quanto a constituírem espécies distintas ainda não é bem definido. A identificação das espécies que compõe um recurso pesqueiro é imperativa não somente pela importância ecológica, mas também do ponto de vista da gestão do recurso. A análise multivariada de um conjunto de caracteres fenotípicos é um dos métodos apropriados para esclarecer relações morfológicas de diferentes populações de diferentes espécies. Os padrões de discriminação morfológica entre Rhizoprionodon porosus e Rhizoprionodon terraenovae foram estudados através de técnicas de análise estatística multivariada, com o objetivo de avaliar o status das espécies e determinar se os caracteres morfométricos podem ser usados na discriminação. Com base em uma amostra de 79 indivíduos coletados em 3 localidades (Pernamuco e Rio Grande do Norte, Brasil e Flórida, EUA) e 67 parátipos de ambas as espécies depositados nos Museus MN/UFRJ, MZUSP, MOVI, MNHN e FMNH, analises multivariadas foram realizada com base em 64 medidas morfométricas. Os resultados indicaram diferenças significativas entre exemplares de R. porosus e R. terraenovae. Grupos distintos de ambas espécies foram formados tanto na análise de agrupamento quanto na análise discriminante, exemplares com classificação divergente da análise são em maioria provenientes da América Central. Os resultados indicam que R. terraenovae e R. porosus podem ser consideradas espécies distintas, simpátricas apresentando miscigenação na área da América Central.