Search

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2018-05-23T14:34:39Z No. of bitstreams: 1 PDF - Fernando José König Clark.pdf: 28050270 bytes, checksum: 6d4e4eb2167c1e7ae74f3548b604008b (MD5) Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2018-05-23T16:49:35Z (GMT) No. of bitstreams: 1 PDF - Fernando José König Clark.pdf: 28050270 bytes, checksum: 6d4e4eb2167c1e7ae74f3548b604008b (MD5) Made available in DSpace on 2018-05-23T16:49:35Z (GMT). No. of bitstreams: 1 PDF - Fernando José König Clark.pdf: 28050270 bytes, checksum: 6d4e4eb2167c1e7ae74f3548b604008b (MD5) Previous issue date: 2018-02-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq The inner ear of teleostean fishes has internally hair cells which in contact with otoliths is responsible for orientation and balance and hearing, providing positioning and movement senses. The semicircular canals house the three otoliths suspended in liquid, connected to the optical membranes, being sagittae, used as chronological structure because they are not reabsorbed after their formation by the deposition of calcium carbonate, creating rings making the analysis of this structure on studies of aging and the use of the habitats in which they pass part of their life cycle. Dependent on genetic and environmental factors, the otolith forms are species specific, thus functioning as markers of both the different environmental conditions the fish are subjected to and the characteristic phylogenetic patterns found in the families to which each species belongs. For this, estuaries are important coastal environments for the initial stages of fish life, which provide them with better feeding conditions. However, fish are submitted to environmental factors governed in part by hydrological conditions, which influence salinity, temperature, turbidity and primary productivity. Therefore, the study of t he shape of otoliths is useful for the identification of Atherinella brasiliensis populations, a species with wide distribution in shallow water environments of the Brazilian coast, forming large schools, and important for the beginning of the trophic chains. Considering this, it was sought to understand how the development of otoliths in two distinct environments, mainly in relation to the salinity gradient, and between the juvenile and adult phases, comparing the populations of these environments and thus seeking a better ecological understanding for future projects. management. A total of 1,190 individuals (3,357 g) were captured, distributed between 633 to the Mamanguape estuary and 457 to the Tubarão estuary. The sagittae otoliths presented a general elliptic, concave-convex shape. The morphometric parameters were higher for the upper zones of the studied environments. The indices of ellipticity and shape factor were higher in the upper estuary and in the hypersaline estuary, and differences were observed only for juveniles and adults, with circularity and rectangular indexes being higher among juveniles. O ouvido interno nos peixes teleósteos, responsável pela orientação e equilíbrio e audição, possui internamente grupos de células pilosas, que em contato com os otólitos, proporcionam funções de posicionamento e movimento. Os canais semicirculares alojam os três otólitos suspensos em líquido, ligados às membranas óticas, sendo o sagittae, usado como estrutura cronológica e para a audição dos peixes. Por não serem reabsorvidos após sua formação pela deposição de carbonato de cálcio, e com a criação de anéis, a analise dessa estrutura possibilita estudos sobre a idade e sobre a utilização dos habitats nos quais passam parte do seu ciclo de vida. Dependentes de fatores genéticos e ambientais, as formas dos otólitos são específicas de cada espécie, assim funcionando como marcadores tanto de condições ambientais diferentes as quais os peixes estão submetidos, quanto a padrões filogenéticos característicos encontrados nas famílias as quais cada espécie pertence. Para tal, os estuários são importantes ambientes costeiros para o ciclo de vida dos peixes, que lhes propiciam melhores condições de alimentação. Entretanto, os peixes são submetidos a fatores ambientais regidos em parte por condições hidrológicas, o que influencia na salinidade, temperatura, turbidez e produtividade primária. Assim sendo, o estudo da forma dos otólitos, é útil para identificação de populações de Atherinella brasiliensis, espécie com ampla distribuição em ambientes de águas rasas do litoral brasileiro, formadora de grandes cardumes, e importante para o início das cadeias tróficas. Visto isso, buscou-se entender como desenvolvimento dos otólitos frente a dois ambientes distintos, principalmente, quanto ao gradiente de salinidade, e entre as fases juvenil e adulta, comparando as populações desses ambientes e assim, buscando uma melhor compreensão ecológica para futuros projetos de manejo. Foram capturados 1.090 indivíduos (3.357g), distribuídos entre 633 para o estuário do rio Mamanguape, e 457 para o estuário rio Tubarão. Os otólitos sagittae apresentaram forma geral elíptica, côncavo-convexa. Os parâmetros morfométricos foram maiores para as zonas superiores dos ambientes estudados. Os índices de forma elipsidade e fator de forma foram maiores na zona superior do estuário positivo e no estuário hipersalino, e diferenças foram observadas apenas para juvenis e adultos, sendo os índices, de circularidade e retangularidade maiores entre os juvenis.

The objective of this study was to compare two different morphometric methodologies - traditional measurements and truss networks - based on two species of silversides, Odontesthes bonariensis (Valenciennes, 1835) and O. humensis De Buen, 1953, to determine which of the methods results in more reliable distinction between groups. The traditional measures do not represent the true fish form because it does not take into account alometric variations or distinct growth stages. The measures with truss networks extend over the fish form thoroughly resulting in complete representation of the fish's body when homologous morphologic points are connected. The two sets of measures used in the principal components analysis resulted in two groups. The first principal component presented similar positive coefficients, being interpreted as a variation of "size", due to different stages of fish growth. The second component presented positive and negative coefficients, with different values that were interpreted as changes in the "shape" of the organisms. As the groups overlapped partially on the second component axis (the one that represents shape), data were adjusted to exclude the size effect. The first component, then, presented positive and negative coefficients that were related to changes in the shape of organisms. The variables with positive coefficients were related to the anterior area of the body, while the negative coefficients were associated with the caudal peduncle. These variables were the same ones found in both the adjusted and non-adjusted analysis. This study showed that measures with truss networks represented more clearly the difference between groups of O. bonariensis and O. humensis, than with the traditional measures.

The silverside, Atherinella brasiliensis (Quoy & Gaimard, 1824), a resident species of the shallows of bays, estuaries and coastal lagoons, was studied during two annual cycles, using beach seines (July 1996 to June 1998), in the continental margin of the Sepetiba Bay, aiming to assess recruitment and distribution patterns. A wide recruitment period, with young-of-the-year appearing from early spring to early autumn, was shown, with peaks of juveniles (Total Length-LT = 10-30 mm) being recorded in two periods of the year; one in November and another in March. The highest abundances, of both juvenile and adults, were recorded in Coroa Grande and Itacuruçá, sites located in the outer Bay, during the whole summer, with significant differences were found. In spite of not having been found any statistically significant relationship between the environmental factors and the occurrence of this species, a trend of higher abundance in colder and more saline waters was detected. High values of growth coefficient (K = 0.93) and low asymptotic lenght (L∞ = 11.6 cm) indicated that this species shows a high growth rate and short life cycle, with life span of 3.09 years, in this system.

Atherinella blackburni (Schultz, 1949) (Atherinopsidae), is known in the Atlantic Ocean in Costa Rica, south of Caribe and from Venezuela to central Brazil. The distribution and the intraespecific variation of characters of A. blackburni are poorly known. This study records A. blackburni in Bahia littoral and presents more informations about its intraespecific variation.