Registro:
| Documento: | Tesis Doctoral |
| Disciplina: | biologia |
| Título: | Patrones de distribución espacio-temporal de los estadíos embrionarios y larvales de la anchoita (Engraulis anchoita Hubbs & Marini) a micro y macro-escala. Su relación con la supervivencia y el reclutamiento |
| Autor: | Sánchez, Ramiro Pedro |
| Editor: | Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales |
| Lugar de trabajo: | Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP)
|
| Publicación en la Web: | 2017-03-01 |
| Fecha de defensa: | 1995 |
| Fecha en portada: | 1995 |
| Grado Obtenido: | Doctorado |
| Título Obtenido: | Doctor en Ciencias Biológicas |
| Departamento Docente: | Departamento de Biología |
| Director: | Dz de Ciechomski, Janina Y. |
| Idioma: | Español |
| Formato: | PDF |
| Handle: |
http://hdl.handle.net/20.500.12110/tesis_n2814_Sanchez |
| PDF: | https://bibliotecadigital.exactas.uba.ar/download/tesis/tesis_n2814_Sanchez.pdf |
| Registro: | https://bibliotecadigital.exactas.uba.ar/collection/tesis/document/tesis_n2814_Sanchez |
| Ubicación: | BIO 002814 |
| Derechos de Acceso: | Esta obra puede ser leída, grabada y utilizada con fines de estudio, investigación y docencia. Es necesario el reconocimiento de autoría mediante la cita correspondiente. Sánchez, Ramiro Pedro. (1995). Patrones de distribución espacio-temporal de los estadíos embrionarios y larvales de la anchoita (Engraulis anchoita Hubbs & Marini) a micro y macro-escala. Su relación con la supervivencia y el reclutamiento. (Tesis Doctoral. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales). Recuperado de http://hdl.handle.net/20.500.12110/tesis_n2814_Sanchez |
Abstract:
This dissertation is focused on the study of implications of spatial patterns onsurvival of eggs and larvae and subseguent recruitment of the SW Atlantic anchovy, Engraulis anchoita. The study of distribution patterns is encompassed within theconceptual framework of the analysis of reproductive strategies of marine bony fish,as adaptations that enable them to cope with and active y exploit environmentalvariability, regulating their abundance and avording extinction. The Southwest Atlantic anchovy, is ideally suitable for studies on reproductivebiology and recruitment on a comparative basis. Its spawning and nursery groundsare located in very diverse ecosystems. This variety refers to their physico-chemicalproperties, carrying capacity, the influence of several water masses, and thecontribution of fresh water runoffs from different origins. Important physical featuresare seasonal thermocline formation, and the presence of transitional regions such asoceanic, shelf-break and tidal shelf fronts, an upwelling areas. The aim of this dissertation was to study the biological response to thatenvironmental heterogeneity. The central issue of the discussion was the implicationof that apparent lack of association between reproductive activity and environmentalconditions, on the rates of growth and mortality during the early developmentalstages, and subsequent recruitment. As a working hypothesis we postulated theexistence of some egree of dependence between those opulation attributes and theevolution of the distributional patterns during the early ontogeny. To prove thisassumption we studied distributions not only in their usual connotation (i.e. spatialarrangement, geographic location),but also in their ecological and statistical sense, in a variety of time-space scales, from the Eulerian and Lagrangian perspectives. The final outcome, based on the identification of factors influencing the survival ofthe early developmental stages of the species, was the derivation of models thatcould describe mechanisms o demographrc regulation. Chapter I introduces notions which compound the theoretical basis of thisdissertation. Among them are such concepts as: reproductive strategies, marine fishrecruitment and population regulation, distributional patterns, time-space scales, andthe comparative approach as an alternative to the experimental application of thescientific method. A synthesis on the existing information about reproductive biology and early life history of the species is included. A glossary including terms usedfrequent y along this dissertation has been prepared, with the aim to clarify theirorigin meaning and equivalencies, particularly in the case of personal translations. Chapter II contains all the basic details about the samples analyzed, withinformation on the time-space location of the cruises and stations, on the samplersutilized, on the sampling and laboratory techniques applied, on the statisticalhandling of information and data processing. The present taxonomic status of the genus Engraulis is discussed in Chapter III. Spawning and nursery grounds of all the Engraulis species are reviewed on a comparative basis. A detail analysis is presented on the current knowledge about the spawning grounds of E. anchoita in the SW Atlantic, including a seasonalcomposite of environmental conditions prevailing in the spawning grounds of the species of the Argentine Sea and Common Fishing Area with Uruguay. Chapter IV is devoted to the analysis of the monthly evolution of spawningpatterns based on a historical data series, covering the period 1966-1989. Themethodology involved includes the pooling of available information into 30’ latitudex 30’ longitude statistical rectangles. Monthly maps were constructed representingaverage spawning, percent incidence by rectangle, identification of reproductionnuclei and location of nursery grounds. Monthly vanation of reproductive intensity isanalyzed as a function of temperature, latitude, depth, distance from shore and theabundance of zooplankton an other ichthyoplankton. Monthly regional census ofegg and larvae production were calculated on the basis of monthly variations in meanproductions an geographical extensions of the spawning and nursery grounds. Patterns of eggs and larvae distributions are statistically analyzed in Chapter V through the application of several indexes and ecological models to our historicaldata series. A simulation exercise is used to discuss the efficiency of two models forthe estimation of population parameters from an increasing number of samples. Also included is a practical application resulting from the fitting of these statisticaldistributions is the estimation of the sampling effort required in order to detectvariation in the population abundance with different degrees of precision. Some characteristics of the spatial pattern of distribution of anchovy eggs, such as patch size and aggregation are studied. A comparative analysis is presented on theecological implications and adaptive advantages of the evolution of distributionalpattern in the course of ontogeny. Growth during the anchovy early life history is the subject of Chapter VI. Amodel is developed for the age determination of anchovy eggs developed at fourdifferent experimental temperatures. Results are reported on the experimental growth of yolk sac larvae. The first results are presented on the daily growth of the speciesduring the larval and post-larval stages from countings of otolith rings. Length-weightfunctions representing larval growth from hatching to metamorphosis were fitted. Multiple regression analysis was used to derive a model to predict larval growthfrom morphometric measurements. A detailed comparative analysis is presented onegg and larval growth of related species. Chapter VII deals with mortality during the anchovy early life stages. Majorcauses or embryonic and larval in marine fish are analyzed. The methodology for thecalculation of field estimates of egg and larval mortality is developed. Results arepresented on the embryonic mortality during the spring spawning peak on the continental shelf off Buenos Aires Province during the period 1967-1970. Planktoniceggs were grouped into age classes following the methods developed in the previouschapter. The weighted negative binomial distribution was applied for the calculationof larval length class frequencies, covering the period 1973-1989. Instantaneousestimates of egg and larval mortality were obtained applying a model of constant exponential extinction. A detailed analysis is presented on the procedure followed forthe calculation of weighting factors for sampler efficiency, mesh selectivity anddiurnal avoidance, and corrections for pre and post-mortem larval shrinkage and forthe variable duration of each size class. The validity of exponential extinction curvesto model early ontogeny mortality by means of log-linear and non-linear fittingprocedures is discussed. An attempt to estimate embryonic and larval mortality by Eulerian re-sampling of a plankton patch is reported. Based on the concept ofsaltatory ontogeny the pre-metamorphic phase was divided into four developmental stages, modeling the evolution of instantaneous mortality estimates through thatphase by means of the Weibull function. A detailed comparative analysis is presentedon egg and larval mortality of related species. Chapter VIII is devoted to the study of reproductive strategies of marine fishfrom an analysis of spawning behaviour of the anchovy under variable environmentalconditions. Chronologically arranged maps with the distribution of eggs, larvae andatitudinal changes in larval size frequency distributions are reported. Seasonalvariations of early life history stages vertical distribution, in both regions, areanalyzed. Current knowledge on hydrographical structures and Circulation over thecontinental shelf and slope is use to infer the final fate larvae at metamorphosis. Based on a comparative analysis of embryonic and larval growth and mortality,larval feeding activity and condition and reproductive parameters a discussion ispresented on the potential of the two areas as spawning and nursery grounds. Research detailed in Chapter IX is based on a survey designed to reduce thetime-space observational scales and to alter of perspective in the study of egg andlarval pattern and survival. Lagrangian changes in distribution and survival within ananchovy egg and larvae patch were studied by means of multiple opening/closing sampling following a free drifting buoy. The drifter was launched on the Buenos Aires continental shelf, off Necochea during the spring spawning peak of 1983. Three discrete depths (within, below and above the thermocline) were repeatedlysampled close to the drogue were monitored at 3/4 hour intervals for a period of three days. The efficiency of the drogue as a Lagrangian marker was examined by meansof the application of multifactorial ANOVA to test the significance of variabilitybetween days, light regime, sampling depths, population structure and theirinteractions. Wind drag on the surface unit did not significantly affect the trajectoryof the drogue. Patterns of embryonic and larval vertical distribution are discussed bymeans of the variations in the centre of mass, in the vertical dispersion andpatchiness indexes for each developmental stage analyzed. There is evidence of dielbvertical migration in larvae larger than 8 mm SL. Although the incidence of feedin Consulte el resumen completo en el documento.
Citación:
---------- APA ----------
Sánchez, Ramiro Pedro. (1995). Patrones de distribución espacio-temporal de los estadíos embrionarios y larvales de la anchoita (Engraulis anchoita Hubbs & Marini) a micro y macro-escala. Su relación con la supervivencia y el reclutamiento. (Tesis Doctoral. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales.). Recuperado de https://hdl.handle.net/20.500.12110/tesis_n2814_Sanchez
---------- CHICAGO ----------
Sánchez, Ramiro Pedro. "Patrones de distribución espacio-temporal de los estadíos embrionarios y larvales de la anchoita (Engraulis anchoita Hubbs & Marini) a micro y macro-escala. Su relación con la supervivencia y el reclutamiento". Tesis Doctoral, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, 1995.https://hdl.handle.net/20.500.12110/tesis_n2814_Sanchez
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