Tulane University

Resources: Technical Paper

Techniques for the Determination of Clutch Parameters in Darters and Minnows:
A Proposal for Standard Methods by David C. Heins

Figures

Click for Full Image.Figure 1

Ventral view of ovaries from mature (MA) female of Etheostoma caeruleum. Two entirely separate groups of oocytes are present in the follicles: smaller maturing oocytes and larger mature oocytes. A histogram showing a plot of oocyte size versus percentage frequency of occurrence from the ovaries would show to entirely separate groups of oocyte. Size is the primary criterion as color may vary. A female (ovaries) with but one group of oocytes even if bimodal would be classified as late maturing (LM).

Click for Full Image.Figure 2

Ventral view of ovaries of mature (MA) female of Etheostoma caeruleum. In addition to smaller maturing oocytes, a group of larger maturing oocytes is present in the follicles. The mature oocytes are opaque, and the chorions are not elevated.

Click for Full Image.Figure 3

Ventral view of ovaries of ripening (MR) female of Etheostoma caeruleum. The group of larger gametic cells which is present in the follicles are ripening oocytes undergoing final oocyte maturation. The ripening oocytes are translucent to sometimes transparent and the chorions are elevated from the yolk mass.

Click for Full Image.Figure 4

Ventral view of ovaries of ripe (RE) female Etheostoma caeruleum. Only smaller maturing oocytes are present in the follicles. The larger gametic cells are ripe eggs which are ovulated and occupy the lumina in the centers of the ovaries. The ripe eggs are translucent to transparent and have elevated chorions. The eggs are lumped together. Thus, they only need to be separated from one another after the entire man is separated from the maturing oocytes. Mature and ripening oocytes must be extracted from the individual follicles and are distributed among the smaller maturing oocytes.

Click for Full Image.Figure 5

Ventral views of ovaries from mature (MA), ripening (MR), and ripe (RE) females of Etheostoma caeruleum. Note that in each case smaller maturing oocytes are present in addition to a group of larger gametic cells. In mature ovaries, the group of larger gametic cells is comprised of mature oocytes; and in ripening ovaries, the group of larger gametic cells is comprised of ripening oocytes. In ripe ovaries, the larger gametic cells are ripe eggs.

Click for Full Image.Figure 6

Variation in mature ovaries of Etheostoma caeruleum females.

Click for Full Image.Figure 7

Variation in ripening ovaries of Etheostoma caeruleum females.

Click for Full Image.Figure 8

Variation in ripe ovaries of Etheostoma caeruleum females.

Click for Full Image.Figure 9

Mature, ripening and ripe ovaries of Etheostoma simoterum females.

© Copyright 1995 by David C. Heins, All rights reserved.

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