FISHERY BULLETIN; VOL. 83, NO. 2 



Figure l. — Development of northern anchovy ovary at various magnifications (stain = H & E, bar = 0.1 mm), a) Immature ovary 

 consisting of unyolked oocytes and no atresia, b i Enlargement of (a I showing small spherical unyolked oocytes (U) with a large central 

 nucleus and "oogonium nests" (o). c) Normal mature ovary with many fully yolked oocytes (Y). d) All stages of oocytes: unyolked (U), 

 partial yolked (Pi, and yolked (Y), are present in normal mature ovaries, (g = granulosa cell layer, z = zona radiata, n = nucleus, y = 

 yolked globules.) e) Prespawning ovary showing migration of nucleus to the animal pole, f) Enlargement of a migratory nucleus 

 oocyte (M). (n = nucleus, y = yolk globules.) g) Imminent (• 12 h) spawning ovary with hydrated oocytes (H) still within the follicle 

 layer (U = unyolked, P = partial yolked. ) h ) Enlargement of a hydrated oocyte. Note that the yolk globules have fused into yolk plates 

 (yp) and there is no prominent nucleus due to disintegration of the nuclear membrane. 



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