Oogenesis in the amber-jack Seriola dumerili Risso, 1810 : an histological, histochemical and ultrastructural study of oocyte development

Altres ajuts: CICYT/MAR91-0638Macroscopic and microscopic characteristics of the maturity stages of the ovary of the amberjack Seriola dumerili. Risso are reported. Oogonia. Oocytes at different stages of development. Follicular and thecal cells, ant postovulatory follicles are described following a light and transmission electron microscope study. Histological observations of oocyte development show that the oocyte diameter increases about 100 fold during oogenesis, the nucleus-to- cytoplasm-ratio ranging from 72% (in oogonia) to 18% (in mature oocytes just before the breakdown of the germinal vesicle). Histochemical and ultrastructural studies show that three types of inclusions are formed during vitellogenesis. Lipid globules (exclusively composed of carbohydrates). Yolk granules, which contain glycoproteins, glycogen and lipids appear last. The location and movements of these inclusions within the oocyte cytoplasm during oogenesis are described. The vitelline envelope or zona radiata (ZR) is first seen at the lipid globule stage I as a discontinuous layer. The structure, mainly proteinaceous in nature. Increases in thickness as oogenesis proceeds and peaks (33 µm) during the maturation phase

Oogenesis in the amber-jack Seriola dumerili Risso, 1810 : an histological, histochemical and ultrastructural study of oocyte development

Macroscopic and microscopic characteristics of the maturity stages of the ovary of the amberjack Seriola dumerili. Risso are reported. Oogonia. Oocytes at different stages of development. Follicular and thecal cells, ant postovulatory follicles are described following a light and transmission electron microscope study. Histological observations of oocyte development show that the oocyte diameter increases about 100 fold during oogenesis, the nucleus-to- cytoplasm-ratio ranging from 72% (in oogonia) to 18% (in mature oocytes just before the breakdown of the germinal vesicle). Histochemical and ultrastructural studies show that three types of inclusions are formed during vitellogenesis. Lipid globules (exclusively composed of carbohydrates). Yolk granules, which contain glycoproteins, glycogen and lipids appear last. The location and movements of these inclusions within the oocyte cytoplasm during oogenesis are described. The vitelline envelope or zona radiata (ZR) is first seen at the lipid globule stage I as a discontinuous layer. The structure, mainly proteinaceous in nature. Increases in thickness as oogenesis proceeds and peaks (33 µm) during the maturation phase

Informe Taller Pesquerias Artesanales y Recreativas

En el taller se han realizado más de 20 presentaciones acerca de los estudios sobre las pesquerías artesanales y recreativas en aguas de la ZEE de España. En base a ello y al conocimiento de los expertos reunidos se han definido dos planes de seguimiento para obtener la huella pesquera de las pesquerías profesionales sin VMS, uno con sistemas de seguimientos de localización en tres fases y otro con observadores a bordo y encuestas en puntos de primera venta en dos fases. En el caso de las actividades pesqueras no profesionales (recreativas) se ha propuesto un plan de seguimiento basado en encuestas telefónicas y presenciales en tres fases. Además se decidió incluir las actividades pelágicas y/o de superficie dentro de los programas de seguimiento